the precision of an aggregate particle size and shape test

The precision of an aggregate particle size and shape test

S.G.C. Servais and K.I. York

ABSTRACT

Roads Corporation Victoria specifications for crushed rock aggregates for use in sprayed bituminous surfacing contain limits on particle size distribution and the allowable proportion of flat particles present in the aggregate. Flatness is defined in terms of the Flakiness Index test.

This paper describes a study undertaken to assess the precision of the particle size distribution and Flakiness Index tests and of the derived Average Least Dimension value. It also reports the unexpected effect of the type of sieve shaker upon some test results.

The finding of major practical significance was that the precision of the Flakiness Index test is relatively poor. Hence producers must supply a product which has a true value substantially below the specified maximum value in order to have a high probability of the product being accepted.

86 Vol.2 No.2 June 1993 ROAD & TRANSPORT RESEARCH

===i==;zz=====zzz===z=z=z=;zz•.=;zzz;===z=====z===zzzz Aggregate particle size and shape

R oads Corporation Victoria specifications for crushed rock aggregates for use in sprayed bituminous surfacing contain

limits on the allowable proportion of flat particles present in the aggregate. Flatness is defined in terms of the Flakiness Index test (AS 1141.15) (SAA 1988). The test involves sorting the aggregate on a set of square aperture test sieves into a number of closely limited particle-size groups, and then separating the particles in each group on a slotted sieve, the slot width of which is 0.6 times the mean of aperture sizes of the two consecutive sieves through which all of the particles passed and upon which all were retained. The Flakiness Index is defined as the percentage by mass of particles which pass the slotted sieves.

In addition to determining the acceptability of an aggregate, the Flakiness Index value is used in calculating the Average Least Dimension (ALD) of the aggregate. The ALD is used to calculate the optimum spreading rate for the aggregate and the application rate of bitumen during the surfacing process. No additional testing is required for the determination ofALD; the value is calculated from results obtained in the sieve analysis and calculated Flakiness Index as follows (Hanson 1935):

ALD —

Median size 1. 09 + (0. 0118 x Flakiness Index)

where the median size is the theoretical sieve size through which 50 per cent of the aggregate would pass.

Vol.2 No.2 June 1993 ROAD & TRANSPORT RESEARCH

The ALD is defined as the average thickness of all the individual particles, weighted in proportion to the surface area covered, when the particles lie with their least dimension upwards.

Roads Corporation specifications for aggregates to be used in the production of asphalt and concrete also contain limits for Flakiness Index.

This paper describes a study undertaken to assess the precision of the sieve analysis and Flakiness Index tests and the ALD determination. The precision of a test is often quantified in terms of its repeatability and reproducibility, which terms can be defined as follow:

• Repeatability. The largest difference that could be expected, to a probability of 95 per cent, between two random test results obtained by the same operator, using the same equipment on identical portions of material over a short time interval.

• Reproducibility. The largest difference that could be expected, to a probability of 95 per cent, between two test results which have each been obtained by different operators, using different equipment in different laboratories at different times on identical portions of material. It is assumed that each laboratory carried out the tests strictly in accordance with the standard procedure and that the differences between results are not caused by errors or anomalies.

Since, in practical terms the concept of identical portions can rarely be realised, values of reproducibility and repeatability for a particular

87

Agg re g ate article size and sha pe

test are usually obtained by having a large number of operators each carry out repeat tests on portions of material carefully split from a homogeneous sample.

There is an increasing need within the Roads Corporation to gain knowledge of the precision of tests used for the acceptance of materials and work. Until recently, all acceptance testing associated with Corporation works has been carried out by the Corporation. From now on, contract works are to be performed under contractors' quality systems which, inter alia, places the responsibility for acceptance testing with the contractor. Hence the need to be aware that different laboratories, within or outside the Corporation, cannot be expected to produce identical results from the tests on the same material, and to gain an understanding of the magnitude of the differences that must be expected.

The tests chosen for this study are among the most frequently performed tests within the Corporation.

Testing program Two bulk samples of 10-mm, nominally one-sized, aggregate produced by crushing basalt were obtained, each from a different quarry in the Melbourne area. The sources were selected on the basis that the two aggregates were very similar in appearance.

Each bulk sample was thoroughly mixed and then very carefully split into 128 close-to-equal sized portions of the size required by the method for the Flakiness Index test. Initially the bulk samples were split by cone-and-quartering, then by using an eight-chamber rotary splitter and finally by a riffle box.

Two portions of each bulk sample were randomly selected and issued in one operation to 50 operators who were well experienced in carrying out the test, in 10 Roads Corporation laboratories. The operators were led to believe that the portions they received had come from four different sources. This was done to eliminate the risk of the test results being influenced by the operators' possible expectations when replicating tests. The operators were instructed that no further preparation e.g. washing or splitting, was to be carried out on the portions prior to testing. The tests to be carried out were sieve analysis and Flakiness Index and, from the results of these, the operators were to determine the median size and ALD of each portion.

88

Statistical analysis

Estimates of repeatability and reproducibility can be determined simply from the within-laboratory and between-laboratory variances calculated from the test results. However, these estimates can be flawed if there exist any interactions between, say, laboratories and materials, i.e. if the pattern of change of the results obtained on a given material in one laboratory differs from the pattern obtained in another laboratory (ASTM 1987). The statistical technique of analysis of variance (ANOVA) can be used to discover the existence of any significant interactions, and to calculate the appropriate variance from which to obtain the best estimate of repeatability and reproducibility.

As the name implies, the ANOVA procedure attempts to analyse the total variation of a response by breaking it down into independent and meaningful portions attributable to each of the independent variables and to chance variation. The chance variation category includes the net effect of all variables not explicitly included in the analysis. The objective is therefore to identify important independent variables, and to determine how they interact and affect the response (Chou 1975).

Test results

Sieve analysis

General

The sieve analysis data were submitted to a statistical program for the purposes of checking the accuracy of computations and determining for each of the sieve sizes, the maximum, minimum, mean and standard deviation of the percentages passing the sieve, for each laboratory, for each of the two samples. Computational errors detected were corrected. Test results are summarised in Table I.

Analysis of variance

In this study the percentages passing the 9.50 and 6.70 mm sieves are the most relevant, as they constitute the fractions used in determining the Flakiness Index. Consequently, the data for these sieve sizes only were submitted to analysis of variance.

The assumptions underlying the ANOVA require that the differences between repeat tests be


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TABLE I

Summary of sieve analyses (corrected)

(% passing)

Sample A 13.2 mm Lab. (No. of operators) mean range

9.50 mm mean range

6.70 mm mean range

4.75 mm mean range

3.35 mm mean range

2.36mm mean range

1 (9) 100.0 0.0 83.2 8.1 10.4 3.7 2.1 0.6 1.4 0.5 1.1 0.3

2 (4) 99.3 3.4 82.9 17.1 10.1 3.3 2.2 0.5 1.6 0.4 1.2 0.5

3 (4) 100.0 0.0 84.4 7.8 14.6 4.0 1.9 0.3 1.3 0.5 0.9 0.3

4 (6) 100.0 0.0 81.9 6.8 13.6 5.3 2.0 2.3 1.2 1.9 0.9 1.8

5 (5) 100.0 0.0 85.5 8.6 15.3 5.1 2.3 0.9 1.4 0.6 1.1 0.4

6 (6) 99.6 4.4 85.6 3.8 13.4 5.4 2.2 1.2 1.7 1.0 1.3 0.8

7 (4) 100.0 0.0 81.4 12.2 10.7 3.1 2.0 0.8 1.4 0.4 1.2 0.3

8 (4) 99.5 4.3 78.8 5.0 15.3 6.4 2.0 0.6 1.1 0.4 0.8 0.4

9 (5) 100.0 0.0 81.1 8.9 14.2 7.2 1.8 1.1 1.1 0.6 0.8 0.4

10 (3) 100.0 0.0 80.4 5.6 11.2 2.5 2.2 0.3 1.6 0.3 1.3 0.3

Weighted (50) 82.8 17.3 Mean

Sample B

1 (9) 100.0 0.0 98.8 2.5 11.5 4.2 2.1 0.9 1.7 0.5 1.4 0.4

2 (4) 100.0 0.0 98.2 1.8 11.0 3.0 2.1 0.7 1.6 0.5 1.4 0.4

3 (4) 100.0 0.0 99.6 1.4 18.7 5.5 1.6 0.4 1.2 0.4 0.9 0.2

4 (6) 100.0 0.0 98.7 4.4 17.0 8.0 1.4 0.7 0.9 0.6 0.7 0.5

5 (5) 100.0 0.0 99.2 2.3 18.3 4.7 2.0 1.1 1.6 0.8 1.3 0.7

6 (6) 100.0 0.0 99.4 1.4 16.2 13.2 2.5 1.1 2.0 0.9 1.7 0.9

7 (4) 100.0 0.0 98.9 3.2 12.5 4.0 2.3 0.5 1.8 0.4 1.5 0.3

8 (4) 100.0 0.0 98.6 3.2 18.8 6.4 1.6 0.8 1.0 0.6 0.8 0.7

9 (5) 100.0 0.0 98.7 6.4 18.1 4.4 1.5 1.0 1.0 0.7 0.8 0.6

10 (3) 100.0 0.0 98.5 2.8 13.6 7.1 2.3 0.4 1.9 0.2 1.6 0.2

Weighted (50) 98.9 15.4 Mean

normally distributed. Hence the data were subjected to the Cochran test (Bowker and Lieberman, 1972), to detect any outlying difference between repeat tests, ie. any difference not belonging to the distribution under analysis. The results from one operator were shown to be outliers and were consequently removed from the data. The assumptions also require that the mean results for each operator be randomly distributed. Hence the data were tested in the manner set down by American Society for Testing and Materials (ASTM 1980). The results of two operators were shown to be discrepant and were removed; one of these operators was the one whose results failed the Cochran test. A similar


process of statistical test was applied to the deviations of each laboratory mean from the grand mean for each sample. No outliers were detected in this case.

The study was originally designed to estimate the amount of variation due to the influence of the laboratories/operators (reproducibility) as well as to the experimental error (repeatability). However, observation of the data revealed an unexpected marked polarisation of results for the 6.70 mm sieve and Flakiness Index into two distinct clusters, according to the type of mechanical sieve shaker used during the test. This phenomenon is illustrated in Tables II and VI.

89

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TABLE II

Summary of percentage passing 9.50 mm and 6.70 mm sieves for each type of sieve shaker

Laboratory (No. Operators)

Type of Sieve Shaker Rotary/Hammer Pendulum

Sample Sample A B A B

Sieve Size (mm) Sieve Size (mm) Sieve Size (mm) Sieve Size (mm) 9.50 6.70 9.50 6.70 9.50 6.70 9.50 6.70 (%) (%) (%) (%) (%) (%) (%) (%)

1 (9) 83.2 10.4 98.8 11.5

2 (4) 82.9 10.1 98.2 11.0

6 (6) 85.6 13.4 99.4 16.2

7 (4) 81.4 10.7 98.9 12.5

10 (3) 80.4 11.2 98.5 13.6

Weighted Mean (26) 83.1 11.2 98.8 12.9

3 (4) 84.4 14.6 99.6 18.7

4 (6) 81.9 13.6 98.7 17.0

5 (5) 85.5 15.3 99.2 18.3

8 (4) 78.8 15.3 98.6 18.8

9 (5) 81.1 14.2 98.7 18.1

Weighted Mean (24) 82.4 14.5 98.9 18.1

Two different types of mechanical sieve shakers were in use: a simple pendulum type, and a more sophisticated type that imparted to the nest of sieves a rotary motion in the horizontal plane and applied a vertical hammer blow to a plate fitted above the top sieve in the nest, at the same frequency as the rotation. Five of the laboratories had used the pendulum type and five had used the rotary/hammer type. The ANOVA design was amended to include the extra factor of shaker type, because it was an additional source of variation. Whenever it was necessary to exclude some test results to maintain a balance between the various factors, results were randomly selected

for rejection.

The 'Sources of Variation', 'Degrees of Freedom' (DF) and 'Components ofVariance' for the analysis

of variance are shown in Table III.

and NS are used to designate a significant or non-significant F value, which is the ratio of the mean squares, and the symbol NSR is used to designate non-significant reverse F-ratios at the 0.05 level.

The 9.50 mm sieve

In the analysis, the laboratory - material within shakers (LM(S)) - a type of random laboratory effect - proved significant as well as the variance between materials.

After pooling the sums of squares and degrees of freedom of the non-significant sources of variation, the other variances can be estimated as follows:

From Table IV

E pooled with OM(SL) and O(SL):

VE = 4.038

The analysis of variance for the 9.50 mm and 6.70 mm sieves are shown in Table IV. All values have been multiplied by 1000 to preserve the accuracy of the squares produced by the ANOVA, procedure of the computer program (SPSS Inc, 1983). In these and all subsequent tables, the symbols S

90

LM(S) pooled with L(S), MS and S:

VE + oeVLms = 13.860

VLMS = 1.637


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TABLE III

Analysis of variance: degrees of freedom and components of variance

Source of Variation

DF

Components of Variance

M (between materials)

S (between shakers)

MS (materials - shakers interaction)

L(S) (laboratories within shakers)

1 VE + eVOMSL + oeVLMS + loeVMS + sloe VM

1 VE + eVOMSL + oeVLMS + meVon + moeVLs + loeVms + mloeVs

1 VE + eVOMSL + oeVLMS + loeVMS

8 VE + eVOMSL + oeVLMS + meVOSL + moeVis

LM(S) (laboratories - materials within shakers) 8

O(SL) (operators within shakers-laboratories) 20

OM(SL) (operators materials within shakers-laboratories) 20

E (experimental error) 60

VE + eVOMSL + oeVLMS

VE + eVOMSL + meVOSL

VE + eVOMSL

VE

Sample size, n=120

TABLE IV

Percentage passing the 9.50 mm and 6.70 mm sieves: ANOVA

Source of Variation

Sums of Squares

9.50 mm sieve

Mean Squares

Significance of F Ratio

Sums of Squares

6.70 mm sieve

Mean Squares

Significance of F Ratio

M 8086.850 8086.850 S>.001 217.621 217.621 NS < .10

S 0.114 0.114 NSR < .05 677.825 677.825 NS < .10

MS 0.752 0.752 NSR < .10 25.392 25..392 S > .005

L(S) 149.122 18.640 NS < .25 104.599 13.075 NS < .10

LM(S) 99.492 12.436 S > .005 4.852 0.606 SR > .025

O(SL) 92.887 4.644 NS < .25 172.570 8.628 S > .001

OM(SL) 89.423 4.471 NS < .25 43.090 2.154 NSR < .25

E 221.465 3.691 146.470 2.441

Vol.2 No.2 June 1993 ROAD & TRANSPORT RESEARCH 91

Aggregate particle size and shape

The repeatability (r) of the percentage passing the 9.50 mm sieve can be estimated as:

r = 2 (2 x 4.038) = 5.7 percentage points.

The reproducibility (R) of the percentage passing the 9.50 mm sieve can be estimated as:

R = 2 2(4.038 + 1.637) = 6.7 percentage points.

The 6.70 mm sieve

In the analysis, the operators within shakers and laboratories O(SL), as well as the materials-shakers (MS), interaction emerged as significant sources of variation.

After pooling the sums of squares and degrees of freedom of the non-significant sources ofvariation, the other variances can be estimated as follows:

From Table IV

E pooled with OM(SL):

VE = 2.370

O(SL) pooled with L(S):

VE meVOSL = 9.899 VOSL = 1.882

MS pooled with S and M:

VE + loeVMS = 306.946 VMS = 10.153

The repeatability (r) of the percentage passing the 6.70 mm sieve can be estimated as:


The reproducibility (R) of the percentage passing the 6.70 mm sieve can be estimated as:

R = 2 2(2.370 + 1.882 + 10.153) = 10.7 percentage points.

Flakiness index

General

The Flakiness Index data were checked for computational accuracy and, where necessary, corrected. Test results are summarised in Table VI.

92


As has been described in the case of sieve analysis, the Flakiness Index data were tested for outliers, which resulted in the rejection of one operator's results. The results of the operators who had been rejected from the sieve analysis were also excluded from this analysis of variance. The ANOVA results for Flakiness Index and Average Least Dimension are shown in Table VII.

The 'Source of Variation', 'Degrees of Freedom' and `Components of Variance' for the Flakiness Index (like those for the ALD) are the same as in the case of the sieve analyses (see Table III earlier).

Again the variance between shakers (S) emerged as highly significant and there was also a laboratories within shakers (L(S)) effect and a random effect of operators — materials — shakers and laboratories (OM(SL)), though the latter was onlyjust significant.

After pooling the sums of squares and degrees of freedom of the non significant sources of variations, the other variances are estimated as follows:

From Table WI

E (variance between repeats):

VE = 5.286

OM(SL) pooled with O(SL), LM(S) and MS:

VE eVOMSL = 9.021 VOMSL = 1.868

L(S):

VE+eVOMSL + moeVLS = 35.978

VLS = 2.238

S:

VE + eVOMSL + moeVLS + mloeVs = 318.437 VS 4.709

The repeatability (r) of Flakiness Index, can be estimated as:


The reproducibility (R) of Flakiness Index can be estimated as:

R = 2 2(5.286 + 1.868 + 2.238 + 4.709) = 10.6 percentage points.


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TABLE V

Precision of sieve analysis

Sieve size Repeatability

Reproducibility (mm)

(percentage points)

(percentage points)

9.50

5.7

6.7

6.70

4.4

10.7

TABLE VI

Summary of flakiness index results

Flakiness Index (%) Type of Sieve Shaker

Rotary/Hammer

Pendulum Sample

Sample Laboratory (No. Operators) A

Mean Std Dev B

Mean Std Dev Mean A Std Dev Mean

B Std Dev

1 (9) 26.2 1.7 18.6 1.6

2 (4) 22.6 4.0 19.7 1.8

6 (6) 22.0 1.6 14.5 1.9

7 (4) 24.5 3.2 18.7 1.7

10 (3) 27.8 1.4 17.7 2.2

Weighted Mean (26) 24.6 17.7

3 (4) 19.6 2.3 12.8 1.3

4 (6) 21.8 2.4 16.2 2.8

5 (5) 22.7 3.0 17.4 2.3

8 (4) 21.0 4.3 13.6 3.3

9 (5) 23.3 2.8 14.8 2.1


Average Least Dimension (ALD) General

The ALD results were checked for computational accuracy and, where necessary, corrected. Results are summarised in Table VIII.


As before, the ALD data were tested for outliers, which resulted in the rejection of one operator's results. To maintain a balanced design, the results


of another operator, who used the other type of sieve shaker, were randomly chosen and removed. The analysis is shown in Table VII, shown earlier.

Whereas the analysis of variance on the Flakiness Index showed a significant variance between types of shakers, the above analysis on ALDs could not show the type of sieve shakers to be a significant source of variation; although the mean squares of S is large, the mean squares of laboratories within shakers (L(S)) is also large and indeed proved

93

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TABLE VII

Flakiness index and average least dimension: ANOVAs

Source of Variation

Sums of Squares

Flakiness Index

Mean Significance Squares of F Ratio

Average Least Dimension (mm x 10)

Sums of Mean Significance Squares Squares of F Ratio

M 1307.064 1307.064 S >.001 26.791 26.791 S > .001

S 318.437 318.437 S > .025 47.000 47.000 NS < .05

MS 0.136 0.136 NSR < .05 0.990 0.990 NSR < .25

L(S) 287.027 35.878 S > .005 80.561 10.070 S > .001

LM(S) 89.512 11.189 NS < .25 12.815 1.602 NSR < .25

O(SL) 154.028 7.701 NSR < .25 37.095 1.855 NS < .25

OM(SL) 198.336 9.917 S > .05 49.441 2.472 NS < .05

E 317.160 5.286 91.715 1.529

TABLE VIII

Summary of ALD results

ALD (mm) Type of Sieve Shaker

Laboratory (No. Operators) Mean

Rotary/Hammer Sample

A B Std Dev Mean Std Dev Mean

Pendulum Sample

A Std Dev Mean Std Dev

1 (9) 5.8 0.08 5.9 0.08

2 (4) 6.0 0.17 5.9 0.09

6 (6) 5.9 0.10 6.1 0.08

7 (4) 5.9 0.20 6.0 0.11

10 (3) 5.8 0.07 6.0 0.12


3 (4) 6.1 0.12 6.2 0.06

4 (6) 6.0 0.13 6.0 0.14

5 (5) 5.9 0.14 5.9 0.13

8 (4) 6.1 0.19 6.1 0.16

9 (5) 5.9 0.10 6.1 0.11



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highly significant (as in the analysis on Flakiness Index results). It seems that the variance due to laboratories for each type of shaker has overshadowed the variance caused by shakers.

After pooling the sums of squares and degrees of freedom of the non-significant sources ofvariation, the other variances are estimated as follows:

E (variance between repeats) pooled with OM(SL), O(SL), LM(S) and MS:

VE = 1.762

L(S) pooled with S:

VE + moeVLS = 14.173

VLS = 1.034

The repeatability (r) of ALD can be estimated as:

r = 2 (2 x 1.762) = 0.38 mm.

The reproducibility (R) of ALD can be estimated as:

R = 2 2(1.726 + 1.034) = 0.47 mm.

Conclusion The precision values obtained in the study are summarised in Table IX.

Sieve

A surprising finding was the marked difference between sieve analysis results related to the percentage passing the 6.70 mm sieve for the two

types of sieve shaker. That this effect was not observed for other sieve sizes can be explained by the aggregates being virtually single-sized, with the majority of material being retained on the 6.70 mm sieve; the efficiency of sieving is in part dependent upon the ratio of available apertures in a particular sieve to the number of particles present in the fraction of the sample which pass the sieve immediately above that particular one. Also, particles with a size near that of the aperture may pass the aperture only when presented in a certain orientation and might need many presentations before the required orientation eventuates.

Prior to this study it was generally assumed that the rotary/hammer and pendulum shakers were of equal efficiency. Subsequently a study involving continuously graded materials concluded that the pendulum shaker was the more efficient, even when the sieving time for the rotary/hammer type was greatly increased (Walkom 1986). As a consequence of this, all of the rotary/hammer type shakers in Roads Corporation laboratories were replaced by the pendulum type. This standardisation of shaker type would not be expected to affect the repeatability of the test, but the magnitude of the reproducibility could be expected to be smaller than that reported from this study.

Flakiness Index

The relatively poor precision of this test, i.e. the large magnitude of the ratio of the values of repeatability and reproducibility to the mean test value, indicates its lack of sensitivity to assessed correctly the acceptability or otherwise of an aggregate, the true Flakiness Index of which lies in a relatively broad band straddling the specified limiting value.

TABLE IX

Precision values

Test/Property Repeatability Reproducibility

Sieve Analysis: % passing 9.50 mm sieve 5.7 6.7 % passing 6.70 mm sieve 4.4 10.7

Flakiness Index (percentage points) 6.5 10.6

Average Least Dimension (mm) 0.38 0.47

Vol.2 No.2 June 1993 ROAD & TRANSPORT RESEARCH 95

Aggregate particle size and shape

For example, sample B had a grand mean value of 23.0 % which could reasonably be considered as the `true' value, and the specified maximum value was 25%, which would suggest that the aggregate was quite acceptable. However, 33 of the 100 individual tests were above the specified level and would have led to the rejection of the aggregate. Assuming that no real variation was present in a product, a supplier wishing to have a 95 per cent probability of acceptance of that product would have to keep the true value of Flakiness Index about 5 percentage points, i.e. (r/ 2) below the specified limit if testing was always carried out by the same operator, or about 8 percentage points i.e. (R/ 2) below if testing was by different laboratories. In reality, larger margins would be needed to cater for variation which would exist in the product.

Sample A had a grand mean value of 16.5 %, and every individual test result was below the specified maximum.

As was observed with the sieve analysis data, Flakiness Index values are polarised according to the type of sieve shaker in the laboratory. Although the shaker was not used in separating the particles over the slotted sieves, it was used in sorting the particles into the size fractions used in the test. If, during this sorting, particles which ought to pass

a sieve are retained on it, these particles will almost surely pass the associated slotted sieve and so inflate the value of Flakiness Index. Therefore, as expected, the rotary/hammer shaker which was shown to be less efficient than the pendulum type, is associated with the higher values of Flakiness Index.

Average Least Dimension (ALD) The type of sieve shaker did not have a significant effect on the values of ALD. This can be explained from the expression used to calculate ALD. The less efficient rotary/hammer shaker has been shown to produce relatively larger test values for median size and Flakiness Index; the former appears in the numerator, and the latter in the denominator of the expression, and they tend to balance each other out.

The repeatability value corresponds with a range in the application rate of bitumen in a heavily trafficked situation of about 0.05 L/m2, and the reproducibility value with a range of about 0.06 L/ m2. The spreading rate for aggregate is not as sensitive to small changes in ALD, and so the corresponding ranges would be between 5 m2/m3 and 10 m2/m3, depending on the actual value of ALD (Country Roads Board 1982).1

Acknowledgements This paper is published with the permission of the Chief Executive of the Roads Corporation Victoria,

Mr R. Patterson.

The authors gratefully acknowledge the assistance of their colleagues Kevin Smith and Wendy Harrington, the former for his help in the preparation of samples for testing, and the latter in the word processing of the paper.

96


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References AMERICAN SOCIETY FOR TESTING AND MATERIALS (1980). Standard Practice for Dealing with Outlying Observations — E178-80.

(1987). Standard Practice for Conducting an Interlaboratory Test Program to Determine the Precision of Test Methods for Construction Materials — C802-87.

BOWKER, A.H. and LIEBERMAN G.J. (1972). Engineering Statistics, 2nd ed. Prentice-Hall Inc., New Jersey.

CHOU, Y. (1975). Statistical Analysis, 2nd ed. (Holt, Rinehart, Winston, New York.)

COUNTRY ROADS BOARD (1982). Bituminous Surfacing Manual. (CRB: Kew, Vic.)

HANSON, F.M. (1935). Bituminous Surface Treatment of Rural.Highways. (New Zealand Society of Engineers Inc., Wellington.)

SPSS INC. (1983). SPSS-X User's Guide. (McGraw-Hill: New York.)

STANDARDS ASSOCIATION OF AUSTRALIA (1988). Methods for sampling and testing aggregates. Method 15: flakiness index. AS 1141.15-1988.

WALKOM, D. (1986). Evaluation of the Performance of Mechanical Sieve Shakers. Roads Corporation Materials Branch. Internal Report.

S.G.C. Servais Simone Servais is a graduate in Commercial Economics from the University of Liege in Belgium (1968). As a professional scientist with the Roads Corporation, Victoria, she was involved in statistical analyses relating to field and laboratory testing of pavements and construction materials. After a year of secondment with the Road Infrastructure group of the Australian Road Research Board in 1989, shejoined the Victoria Grants Commission as an econometrician in 1990 and was appointed to the position of Executive Officer and Secretary to the Commission in 1992.

K.I. York Kelvin York has a diploma ofApplied Physics from the Royal Melbourne Institute of Technology. Over a period of 30 years in the Materials Technology Department

of the Roads Corporation, Victoria, his interests covered field and laboratory testing of soils and roadmaking materials, and the associated development of specifications and test procedures. He is currently Quality Service Manager on the

Corporation's Western Ring Road Project involved in the implementation of quality systems into construction contracts. He is a registered lead assessor of quality systems. He has been a member of Standards Australia Committee CE12

- Aggregates and Rock for Engineering Purposes since its inception in 1975 and is Chairman of sub-Committee CE 1215 - Road Base Materials.


97

Oversized containers impact on Australia's road, rail and port facilities

The report in its frontispiece poses the question was Pandora's box really an oversized container. (Pandora's box being 'a present which seems valuable, but which is in reality a curse').

This is an issue facing many countries in that oversized containers offer potential economic benefits to some customers, but may have adverse impacts on land based transport systems and pose safety problems for users of those systems.

The AUSTROADS Council commissioned this report as it wished to know the land and marine implications of the introduction of oversized containers. This was because the State Road Authorities, which comprise AUSTROADS members, are major providers of the nation's transport infrastructure. They are also largely responsible for the administration of road transport. The Council recognised that introduction of containers was an issue for all surface modes —not only roads. Consequently it established a Working Group representing the Federal Department of Transport and Communications, State Road Authorities, Railways ofAustralia, freight forwarders, Standards Australia, stevedores and Port Authorities to examine the issue.

The first task of the Group was to define what was an oversized container. This was taken to be a container which did not comply with the International Organisation for Standardisation (ISO) Standard 668, which provides for containers 10', 20', 30' or 40' long, 8' wide and 8'6" high and provides a maximum weight of24 tonnes for a 20' container. This compares with oversized containers :

• Series I containers — 30' and 40' in length and 8' wide, with height of 9'6";

• Series II containers — 24'6" and 49' in length, 8'6" wide, heights 8'6" and 9'6"; and

• United States Technical Advisory Group for Standardisation of Freight Containers (USTAG) — 40', 45', 48' and 53' in length, 8'6" wide and 9'6" high.

The second task of the Working Group was to assess whether oversized containers were a problem for Australia at present. The assessment was that they are not. This assessment reflected the nature of Australia's export trade, in which the bulk of the commodities suitable for containerisation are high density items such as tinned fruit, dumped wool, steel products and hides, which are more suited to the smaller ISO container. The 20' ISO container is also more suitable for foodstuffs in that it enables better temperature control. Despite this finding the Group concluded that this situation could change rapidly if there was an increased market demand for oversized containers.

In examining the international container trade the Working Group noted the many studies being undertaken by international agencies on oversized containers including ESCAP, UNCTAD and the United Nations Economic Commission for Europe. These studies highlighted international concern about the proliferation of container sizes and the implications this has for the efficiency of the transport chain, in particular the handling of containers at modal interfaces.

Prior to the preparation of this study, the implications for Australian surface transport systems had not been put in international forums. The AUSTROADS Council agreed to the report being presented by the Australian Mission to the

Editor's Note : A new AUSTROADS report on the potential impact of oversized containers was released in May 1993. The Chairman of the Working Group which drafted the report, Jon Bailey, was invited to summarise the report.

98


GATT to the United Nations Economic Commission for Europe Seminar on the Impact of Increasing Dimensions of Loading Units on Combined Transport in Geneva in September 1992. The resolutions of that seminar is an annex to the report. It is worth noting that the findings of the seminar corresponded closely to those of the AUSTROADS Working Group.

In addition to the adverse effects on the efficiency of multi-modal transport due to an increase in the range of container dimensions, the report highlights the impact on individual modes and infrastructure :

• rail — inability to carry oversized containers due to height and width limitations;

• inability to utilise existing rolling stock effectively as it had been designed around ISO standard containers;

• roads — problems with turning movements at intersections, keeping within lanes on curves and an increase in swept path, which would require procedures to restrict vehicles carrying oversized containers to use a limited number of designated routes;

• the combination of increased width and length caused by oversized containers is potentially the most critical dimensional change, because of the effects on road safety;

• lack of clear markings on containers showing weight and dimensions exacerbates an existing management and overloading problem with container vehicles and an increase in container volume would further add to this problem;

• controls may need to be imposed on the movement of oversized containers including : — identification of overdimensional containers, — designation of routes, — width markings, — on-board load weighing equipment, — accreditation of road transport operators;

• marine and terminals — ships would have to undergo significant modification to accept oversized containers and, in many cases, vessels would have to be replaced;

• the efficiency of terminals would be impaired unless substantial modifications were made; and

• most container terminal handling equipment will have to be modified.


The Report also makes a series of recommendations to Ministers, the Federal Department of Transport and Communications, AUSTROADS Members and the National Road Transport Commission :

• drawing attention to the need for uniformity in container dimensions;

• requesting that peak transport bodies be kept informed of developments in the international container trade;

• requesting the development of international markings that would show from a distance the capacity and dimensions of containers;

• suggesting the need for the development of routes for oversized containers ; and

• indicating the need to investigate the need for on-board weighing equipment for container carrying vehicles, accreditation of road operators of vehicles carrying oversized containers.

From a transport practitioner's point of view the report should provide a valuable reference document as it sets out in detail container dimensions, rail loading gauges and road loading requirements. The road and rail sections of the report also contain tables showing how oversized containers could conflict with existing loading requirements. The report also contains a table showing the 'Imperial and metric equivalents measures and weights used' in the report. Finally a word of caution. The report was accurate at the time of writing, however transport is in a period of rapid change. For example, reference is made to state rail systems operating interstate freight services. This will change with the taking over of these services by the National Rail Corporation. Also it is expected that regulations developed by the NRTC will increasingly govern the dimensions and carrying capacities of heavy vehicles.

• Oversized containers. Report AP-103. AUSTROADS. Sydney, NSW 1992. ISBN 0 85588 427 4.

Copies of the report are available from the Australian Road Research Board, PO Box 156, Nunawading 3131, Victoria, Australia, telephone (03) 881 1547, fax (03) 887 8144. Cost $20 plus $3 postage and handling per copy.

99

Dynamic loading of pavements

The OECD Road Transport Research Program is planning a major new study of the effects of heavy vehicle dynamic loading on road and bridge wear, in which Australia will be playing a key role. The study, known as DIVINE (Dynamic interaction between vehicle and infrastructure experiment) will. be carried out by experts from some 17 OECD member countries and will involve specialists on vehicles, pavements, bridges, road management and transport policy.

I )r Peter Sweatman, fbrmerly with ARRB and now Managing Director of his own consultancy firm, Road User Research, is Chairman of this OECD Expert Group, known as I R6. The research to be carried out will be based on the recommendations of an earlier OECD study which Dr Sweatman also chaired. This Expert Group (1R2) published its scientific review of dynamic road loading in October 1992 and its findings were presented at a special seminar in Melbourne in November 1992.

The I R2 report fill' nd thatdynamic pavement loading is currently increasing in OECD member countries, leading to increasing road costs and to constraints on productivity improvements through liberalisation of vehicle weight limits. This trend of increasing road wear can be counteracted by a significant, increase in the use orroad friendly' vehicles (those with air suspensions and/or dual tyres) and by improved pavement, design and maintenance tit navvies.

The HU report, recommended a co-operative int ernat ional research program lx' undertaken. This proposal has been accepted by the OECD and as a consequence the DIVINE project, has been developed.

Objectives of the DIVINE project The scope ofthe research includes vehicle, pavement. and bridge experts as well as vehicle manufacturers and demands international as well as intra (lisciplinal co-operat ion. International co-operation in this project, involving both the vehicle industry and the pavement. community, will save money and improve implementation of the research.

The mina purpose of the research is to improve vehicle coiisl rue( ion, pavement construction and pavement maintenance.

The research will contribute to:

• encouragement of the design and use of road-friendly vehicles and procedures for the design and assessment of the road-friendliness ofvehicles;

• evaluation of the consequences for bridge design of introducing new vehicle technologies;

• lessening of the deterioration of road networks;

• evaluation of policy options pertaining to axle weights, axle configurations and number of axles; and

• allocation procedures for road costs and maintenance planning related to truck weight.

Research program Accelerated dynamic pavement testing will be used to explore the question of the effect of dynamic loading on pavement life and bridge behaviour and essential tools will be developed for measuring, u nderstanding and predicting dynamic loading from heavy vehicles. A further stage of the program may 1 x' needed to extend this knowledge to a representative range of pavements, bridges and vehicle types.

Output The research will provide information on the extent of', and mechanisms of, the effects of dynamic pavement loading on the life of the infrastructure and on means of increasing the road-friendliness of heavy vehicles.

Direct outputs will include:

• new insights for pavement engineers into the design and maintenance of pavements for increased life;

• a method for rating the road-friendliness of vehicles;

• a proven and generally useable computer model of heavy vehicle dynamic loading; and

• information on dynamic bridge loading as influenced by the vehicle suspension type.

100 Vol.2 No.2 Jun© 1993 ROAD & TRANSPORT RESEARCH

Timing and costs It has been estimated that the project, commencing in June 1993, will cost US$1,500,000 and take some two years to complete. For its part, Australia has demonstrated its commitment to the potential savings from this project by undertaking to provide some A$116,000 towards the overall cost. The Federal Government, AUSTROADS, the National Road Transport Commission, Mercedes Benz, York Transport and the Australian Bus and Coach Association have all come together to fund this exciting project, with a number of other transport oriented bodies still considering their position.

Benefits from the study Implementation ofthe IR6 results in Australia would result in substantial productivity improvements for the road transport industry and in reductions in road maintenance costs. It has been estimated that standards relating to heavy vehicle contact pressures and vehicle bounce could save the nation a substantial amount annually in road maintenance costs.

AUSTROADS reference group An AUSTROADS reference group has been established to ensure early and effective dissemination of information flowing from IR6, as well as ensuring its maximum relevance to Australia. The group, comprising representatives from the Federal Department of Transport and Communications, ARRB, NRTC and the road transport industry, has met several times under the chairmanship of the Roads and Traffic Authority, New South Wales.

It is proposed that once the study commences, regular articles will be published in 'Road and Transport Research' on its progress.

Report prepared by Eddie Wheeler, Commonwealth Department of Transport and Communications

VoI.2 No.2 June 1993 ROAD & TRANSPORT RESEARCH 1 0 1

Guide to Traffic Engineering Practice

K

Roundabouts Guide to Traffic Engineering Practice Part 6. AUSTROADS (1993).

A review by Dr R.L. Pretty Department of Civil Engineering The University of Queensland, 4072

AUSTROADS and its predecessor, the National Association of Australian State Road Authorities (NAASRA), have been associated with Guide to Traffic Engineering Practice since 1965 when the first edition appeared. Professional practice has developed considerably over the years, and in 1988 the first parts ofwhat will be a 14-part volume were published. Roundabouts, as Part 6 of the guide, is actually the twelfth to appear and replaces a 1986 NAASRA design guide.

Like the other parts of Guide to Traffic Engineering Practice, Part 6 is a detailed manual for professional engineers and a reference for students. It is the most voluminous of the parts running to 86 pages, but this is appropriate given the complexity of the topic.

AUSTROADS uses corporate authorship, admitting only to a consultant technical writer, Dr Rod Troutbeck, and a technical editor, Mr Ted Barton. Without doubt, the team ofTroutbeck and Barton is an eminent one, giving Roundabouts the potential to develop Australia as having a worldwide reputation for roundabout design and practice. This part forms a companion for traffic signal design, largely developed by Rahmi Akcelik at the Australian Road Research Board, and where Australia already has such a reputation.

Right at the start of the publication there is the very important statement that 'experience and expert opinion vary considerably and practices are still

Guide to Traffic Engineering Practice Part 6 - Roundabouts (AP-11.6193) AUSTROADS. Sydney NSW 1993 ISBN 0 85588 425 8

evolving.' Probably the greatest controversy concerns a matter first raised, as far as this reviewer knows, in Queensland which is the home state of the consultant technical writer, the reviewer and Mr Joe Kenny of the Royal Automobile Club of Queensland. The matter concerns multi-lane roundabouts and the priority for the driver of a vehicle adjacent to the central island wishing to exit and another vehicle in an outer lane, where the driver wished to continue past the exit. It is often argued, as Kenny pointed out, that for this reason multi-lane roundabouts may not attain their full capacity and may create danger


for motorists. Troutbeck, as the writer, tells us how to analyse this situation, and then boldly proposes, at least as an alternative treatment, that circulating and exit lanes be marked according to a certain diagram in Roundabouts to clarify the priority.

The whole of Roundabouts is written to the highest technical standard, giving formulae for performance based on one or two of Troutbeck's publications which have already been reviewed. As a result, I have only two quibbles.

Firstly, the conversion oftruck flows to passenger car units should only be made to measure follow-up headways which are saturation flows. Roundabouts (Part 6) seems to suggest that the conversion be done at the start of the calculations procedure and the converted flows retained throughout.

The other point is that geometric delay should also be defined to include the extra travel distance around a large central island. This would remind the designer that extra travel has a cost to motorists which must be compared in an economic analysis with alternative intersection treatments. Incidentally, in an economic analysis, one of the likely consequences of a roundabout is that there will be a certain excess fuel consumption compared with an alternative form of intersection control. Yet Roundabouts does not tell the reader how to calculate excess fuel consumption; of course computer-based analysis will estimate the amount of excess fuel, one would just like to know the basis for the calculation in the computer analysis.

An interesting sidelight is that the publication gives a rare opportunity to compare two computer-based analysis packages which can be used for roundabouts: SIDRA and INSECT. SIDRA used analytical techniques and less total delay and stops were obtained than for the same example run with INSECT which uses simulation.

To end Roundabouts, there is a full list of references. It is unfortunate that Troutbeck felt compelled to use so many internal reports from within organisations rather than items from the open technical literature. While not disputing the authenticity ofthese citations, Troutbeck should have tried to substitute more open publications, so that readers can better gauge the context of a reference.

Part 6 should join the 11 other published parts of Guide to Traffic Engineering on the bookshelves of professional engineers and university libraries, and then come into steady use so that Australia can have the best possible practice in roundabout design.

$25 per copy plus $3 postage and handling. Available from Australian Road Research Board PO Box 156, Nunawading 3131, Victoria, Australia. Telephone: (03) 881 1547, Fax: (03) 887 8144

VoI.2 No.2 June 1993 ROAD & TRANSPORT RESEARCH 103

2nd International Symposium on

Highway Capacity Sydney, Australia 9-13 August 1994

The Second International Symposium on Highway Capacity is being organised by the Transportation Research Board (USA) Committee on Highway Capacity and Quality of Service and the Australian Road Research Board Ltd.

The Symposium will be held in Sydney in the week preceding the 17th ARRB Conference. Delegates will also be able to attend the Mid-Year Meeting of the TRB Committee on Highway Capacity and Quality of Service, and be given the opportunity to participate in technical tours.

If you wish to present a paper or are interested in attending, please complete the section below.

CALL FOR PAPERS Abstracts of 300- 500 words are required. These should be sufficiently detailed to indicate the context, aim, methodology, results and important conclusions of the work to be reported. (losing date for abstracts is 1 August 1993 and authors will be notified of acceptance or otherwise by 1 October 1993. Full papers will be required by 15 December 1993.

It is important that authors are able to attend and present their papers personally.

104

NEM EMI MIMI MIMI MIN 1111•111 11•1111111 111111•11

I intend to submit an abstract. Please send me further information.

Paper Topic

I I do not wish to present a paper but I am interested in receiving further information about the symposium.

I

I I would also like to receive information on the 17th ARRB Conference, Gold Coast, I Queensland, 14-19 August 1994

Name

Position

Organisation

Address

Tel Fax L .1

Return this form to Dr Rahmi Akcelik, Australian Rood Research Board lid OR PO Box 156, Nunawading 3131, Victoria, Australia

fax 61 3-887 8104

Mr Bill Reilly, IRS Committee A3A10, 7570 N. Palm Circle, Tucson, Arizona 85704, USA Fax 1-602-2918765


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The capacity of the Melbourne rail system A large proportion of atmospheric pollution (including the gases that produce the 'Greenhouse Effect') comes from motor vehicle exhausts. The road networks in major Australian cities such as Melbourne are overloaded, and cannot be expanded except at horrendous financial and environmental cost. Both these problems would be alleviated if a significant proportion of motorists could be persuaded to shift to public transport, especially rail, which has the highest capacity.

Public transport currently carries about 8 per cent of total travel in Melbourne: 16 per cent of work trips and about 5 per cent of non-work trips (Australian Bureau of Statistics 1992; Moriarty and Beed 1992). In the Canadian Municipality of Metropolitan Toronto, the figures are 26 per cent of total travel, 34 per cent of work trips and about 22 per cent of non-work trips (IBI Group 1989).

A number of commentators, most notably the Industry Commission, have objected to the public transport solution on the basis that rail infrastructure is already at capacity in peak periods: 'in the short term the rail system could not accommodate the increases in traffic necessary to provide any significant reduction in car journeys. In the long term an expansion in rail infrastructure would be needed. The cost, both financial and environmental, of such an expansion in a developed city is very high and the benefits are not guaranteed' (Industry Commission 1991). A similar observation is made by Evans (1992).

Vol.2 No,2 June 1993 ROAD & TRANSPORT RESEARCH

This note examines the validity of such objections as they apply in Melbourne.

Estimating capacity Clearly, Melbourne's rail system is grossly underutilised at off-peak times. This is precisely where the greatest scope for improvement in market share exists, since public transport travel is more sharply 'peaked' than overall travel. While Toronto's transit system carries twice as much work travel as Melbourne's, the difference for non-work travel is four to one.

The real 'capacity crunch', however, comes in peak period. What is the capacity of the Melbourne rail system in peak period?

The point of maximum loading is the entry to the central city (the Central Business District and adjacent areas, such as St Kilda Road), where about 300,000 of Melbourne's 1.2 million jobs are located. At this point, the Melbourne rail system provides nine tracks in the peak direction: five through Richmond Station, three through North Melbourne and one through Jolimont. By way of comparison, Sydney's rail system provides six tracks and Toronto's subway four. Terminal space is more than adequately provided by Flinders Street Station's fourteen platforms and the City Loop.

Each of the nine city-bound tracks can handle a train every 2.5 minutes (on most lines, a train every two minutes is feasible, but let's be conservative), or 24 trains per hour. With 40 per cent of passengers

105

standing (current 'crush load' standards permit up to 65 per cent standing passengers), each train carries 1000 passengers. This gives 24,000 passengers per hour per line, a 'relaxed' figure compared with the single peak-direction track of Toronto's Yonge Street subway, which carries 33,000 per hour with a capacity of 36000 per hour (Personal communication from G. Stewart of the City of Toronto Planning and Development Department, 1990).

This is equivalent to 216,000 passengers per hour for the whole system. Since the peak now spreads over at least 90 minutes, the capacity for peak period exceeds 324,000. In other words, there is sufficient capacity to permit the entire central Melbourne workforce to travel to work by rail, with none using trams, buses, cars, walking or cycling! Current peak patronage is about 80,000 or about a quarter this level.

The ultimate capacity of the rail system is even higher, if travellers to intermediate destinations are considered. A passenger travelling from an outer suburb like Lilydale to a middle suburb like Box Hill does not require additional capacity, merely using a train space later filled by a commuter from Box Hill to the central city.

Some history

The 1969 Melbourne Transportation Plan advocated construction of the Underground Rail Loop because existing city terminal space was insufficient to handle projected patronage growth. Daily rail journeys were to rise from 382,000 in 1964 to 663,000 in 1985. The Loop was intended to provide for this level of patronage, and for further increases after 1985 (Melbourne

Transportation Plan 1969). In fact, patronage has fallen since the 1960s to only 250,000 per day, suggesting that the 'loop' is operating at barely a third of its capacity.

Another indication of the extent of surplus capacity comes from changes in the number of trains passing through Flinders Street Station in the busiest hour of the peak. In 1929, the station saw 116 trains leave between 5 to 6 pm (Metropolitan Town Planning Commission 1929), the current figure taken from PTC timetables is only 80! The intervening 64 years have seen the construction of the City Loop, two additional platforms at Spencer Street Station and four more platforms at Richmond.

The extent of unused capacity should not come as a surprise, as Melbourne has one of the largest electrified urban rail systems in the world, as shown in the following table (the data are for 1990/91).

Conclusion

Whichever way one looks at it, Melbourne's rail system appears to be grossly underutilised. A doubling or tripling of patronage is feasible without additional infrastructure. Some more trains may be required, but even here, caution is needed: at present, many trains run half-empty even in peak hours. As indicated in the table, Toronto carries many more passengers with fewer train carriages, so there is considerable spare capacity in the train fleet, as well as in the infrastructure.

Perhaps it's time the role of rail in alleviating pollution and congestion received more serious consideration.

Paul Mees School of Environmental Planning University of Melbourne

Urban area Urban rail line km

Train cars

Passengers (million/year)

Melbourne Paris (Metro) Chicago (CTA) San Francisco (BART) Washington, DC (Metro) Philadelphia Toronto (subway)

329 199 157 115 126 62 60

913 3472 1222

599 664 504 630

95 1228 147

70 144

78 273

Source: Bushell (1992)

106


References

AUSTRALIAN BUREAU OF STATISTICS (1992). Unpublished census data.

BUSHELL, C. (ed.) (1992). Jane's Urban Transport Systems 1992-3. (Jane's Publishing Co.: London)

EVANS, D. (1992) Transport and greenhouse : what won't work and what might work. Papers ofAustralasian Transport Research Forum, Volume 17, Canberra, October 1992, part 3, pp. 835-54.

IBI GROUP (1989) The transportation tomorrow survey, Toronto.

INDUSTRY COMMISSION. (1991) Rail Transport Report, No. 13, p. 192.

METROPOLITAN TOWN PLANNING COMMISSION. (1929) Plan of General Development. (MTPC :Melbourne.)

METROPOLITAN TRANSPORTATION COMMITTEE (1969) Melbourne Transportation Plan Vol. 3, pp. 33-4. (Government Printer : Melbourne.)

MORIARTY, P. and BEED, C. (1992) Explanation of personal travel increases in Australian cities. Papers of Australasian Transport Research Forum, Volume 17, Canberra, October 1992, part 2, pp. 259-70.

Vo1.2 No.2 June 1993 ROAD & TRANSPORT RESEARCH 107

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Queensland Streets Design Guidelines for Subdivisional Streetworks Queensland Streets is a document that provides guidelines for a uniform standard of residential streetworks design, incorporating 'state of the art' principles and techniques. The aim of the document is as a technical support to AMCORD, to provide the more detailed design criteria necessary for the design of streetworks for residential developments in accordance with AMCORD principles.

For some time in Queensland, it has been recognised that the lack of subdivisional engineering standards common to all Local Authorities has been a problem to councils, Consulting Engineers, Developers, Contractors and manufacturers. A uniform subdivisional Streetworks Standard can result in improved efficiency and economy in subdivisional development and hence reduced housing costs.

Queensland Streets has been produced by the Institute of Municipal Engineering Australia -Queensland Division under the Residential

Regulation Review Program. The document has been prepared by Weathered Howe Pty Ltd and has the support of the Queensland Department of Housing, Local Government and Planning and the Queensland Local Government Association.

Queensland Streets

Cost: $50 plus postage and handling $15 (within Australia)

Orders through: The Executive Director IMEAQ PO Box 2100 MAC FORTITUDE VALLEY QLD 4006 Telephone: 07 252 4308, Facsimile: 07 252 4473

'Queensland Streets' is considered to be essential documentation for any Consultant or Authority involved in residential subdivisional works particularly where AMCORD principles are being applied.


ANN( MEE11N; 1993

TR NEW'S

Road Research Down Under The March-April issue of 1'R It News, which is published by the US Transportation Research Board, contains a six page article on the Australian Road Research Board. The article provides an overview of ARRB's research and technology transfer activities in areas including road construction and maintenance, system management, freight, road safety and the environment.

Publication of the article represents an important international recognition of Australian expertise and it will be interesting to see the response generated.

Australian to Join International Research Project Associate Professor Rod Troutbeck ofthe Queensland University of Technology (QUT) Physical Infrastructure Centre (PIC) will join four other traffic engineers selected by the USA National Research Council (NRC) to rewrite the USA Highway Capacity Manual.

The Manual is regarded by many traffic engineers as the standard for analysing traffic behaviour.

The study is in response to problems with the Highway Capacity Manual including regular inconsistencies between predicted and observed conditions. This has affected access management, land use decisions, corridor investigations, signalization needs, operational analyses, safety studies and highway design.

The team will conduct a national field data collection program and validate and calibrate proposed models.


They will also review new procedures developed in Germany and Great Britain, evaluate the performance oftraffic simulation models and rewrite the software code.

Professor Troutbeck is enthusiastic about the project that will continue over two and a half years.

"This is an excellent opportunity to raise the profile of Australian research internationally" Professor Troutbeck said.

Extracted from an article in Physical Infrastructure Centre News (QUT).

Call for Papers for the International Conference on Driver Fatigue, Prolonged Operations & Simulation Organised by the Institute for Research into Safety & Transport, Murdoch University, Western Australia & Sponsored by the W.A. Road Traffic Board and Curtin University of Technology.

Cal for papers and priority registration

Theme

Driver fatigue, prolonged operations & simulation Dates: 16-17 September 1993.

Conference This conference will provide a forum to discuss the impact of fatigue on drivers, methods of study and assessment including driving simulation, suitable guidelines or legislation on hours of work and ensuring compliance with them.

The conference will include keynote addresses from international and Australian researchers on fatigue & simulation. There will also be focused workshops on particular issues such as identifying and measuring fatigue, appropriate guidelines to avoid fatigue and encouraging compliance.

Keynote Speakers include:

Professor Peter Hancock, University of Minnesota on 'Recent studies of truck drivers' fatigue'

Professor Barry Kantowitz, Battelle Labs, Human Affairs Corporation, on 'Field studies ofdriver fatigue'

Dr. Tony Stein, Systems Technology Inc. & Safety Associates on 'Road side testing for fatigue'

109

Dr. Anne Marie Feyer, Worksafe Australia, on 'The ethnography of truck drivers'

Dr. Alan Drummond, Monash University Road Accident Research Centre on 'Driver fatigue studies using a simulator'

Assoc. Professor Kim Kirsner, University of Western Australia on 'Prolonged operational performance and requirements for simulation studies'

Professor Dennis Glencross, Curtin University of Technology, on 'Measures of fatigue and other driving stresses'

Dr. David Sleet, former Director ofRoadwatch, UWA & now Principal Scientist, Centre for Disease Control, Injury Prevention and Accident Control, Atlanta, on 'Public Health Approaches to Injury Prevention and Accident Control'

Invited speakers indude: Bob Mackie, Essex Corporation on 'Long distance truck drivers' fatigue'

Dr Ivan Brown, Applied Psychology Unit, Cambridge U.K. on 'The fatigued driver's assessment of risk'

Dr. Talib Rothengatter, Traffic Research Centre, University of Groningen, on 'Intelligent vehicle methods for combating driver fatigue'

Further information may be obtained from the Conference Convenor or Dr. Anne Marie Feyer, Worksafe Sydney or Dr. Alan Drummond, Monash University Accident Research Centre.

Moveable Medians

Self Propelled Movable Medians were developed in Australia by RTA NSW to provide quick, efficient and safe lane changes on heavily trafficked roads.

They are used to manage peak hour traffic on the Sydney Harbour Bridge and approaches.

The Self Propelled Movable Medians look like the normal concrete median. They provide the security of a physical barrier between lanes and enable more efficient use of traffic lanes.

The moveable medians are made from folded steel modules each 3.6 m long linked together.

1 1 0

One end of the median is fixed and the other free to be driven electrohydraulically. They can be assembled as straights, curves or combinations.

Closed circuit television can be used to assist an operator in a remote control station.

Computer graphics displays can be used to indicate to the operator the existing arrangement and the effect of changes. Once a median is selected for movement the computer can verify that the correct choice has been made.

For further information contact Tony Chan, BME Services Phone (02) 682 9719.

Independent Crash Barrier Test Facility Opened Australia's first independent Crash Barrier Test Facility has been opened by the RTA at Rosebery in NSW.

The Crash Barrier can accommodate cars of all sizes as well as trucks and buses at speeds of up to 100 km/ h. Head-on, rear-end and side collisions can be investigated.

The Barrier will be used primarily to assess the crash-worthiness of vehicles and to test roadside furniture such as safety barriers.

Together with other RTA CRASHLAB equipment it can be used to carry out roll-over tests and to check the frontal design of vehicles to minimise the effect of impacts on pedestrians.

The Barrier, which will be available for commercial use, is already being used in a $2.6 million New Car Assessment Program (NCAP).

The RTA has been commissioned by transport authorities and motoring organisations around Australia to conduct the program.

Dummies will be placed in current model vehicles to compare injury levels and the potential survivability of occupants in crashes.

ARRB's Intersection capacity research highly cost effective A recent audit of ARRB's intersection research capacity has found the work to be highly cost effective.


The audit was conducted in terms of technical merit, research application, benefits from the research and need for further research in the area. Work undertaken between 1979 and 1991 was reviewed. The products of this research are three major reports, the SIDRA software package for the analysis and design of signalised intersections and the ARFCOM software package for estimation of vehicle fuel consumption.

The panel rated the technical merit of the research as very high and concluded that it has established an international reputation for the Board in the fields of traffic signal analysis, roundabout analyses and energy and emission modeling.

The most obvious application of the research is through the widespread use of the SIDRA package. (There are over 250 sets of SIDRA being used in 40 countries, including the USA).

The review panel, headed by Professor Mike Taylor of the University of South Australia, said the SIDRA development is a model example of the successful translation of research into practice.

For further information contact Dr Rahmi Akcelik at ARRB Phone (03) 881 1567.

Energy Savings For Traffic Signals RTA NSW is gradually replacing the incandescent lamps in traffic signals with energy efficient tungsten-halogen lamps.

The 10v lamps have a higher luminous efficiency and smaller filaments than the mains operated lamps which they replace and reduce the energy requirements significantly.

Signal intensities are almost doubled and heat problems eliminated. Further power is saved and lamp life extended by using improved control equipment which incorporates a dimming feature.

There are approximately 2500 traffic signal sites throughout NSW. The annual electricity bill amounts to $4.5 million. When all incandescent lamps are replaced by tungsten-halogen lamps this will drop to about $2.2 million.

VoI.2 No.2 June 1993 ROAD & TRANSPORT RESEARCH

IVHS JOURNAL The Intelligent Vehicle Highway Society ofAmerica has launched a new quarterly journal.

Entitled IVHS Journal and subtitled R&D, Operational Testing, and Deployment of Intelligent Vehicle-Highway Systems the peer-reviewed Journal is to be devoted exclusively to the field of intelligent vehicle-highway systems.

Guidelines for authors are available from:

Dr. Kan Chen, Editor in Chief, IVHS Journal, Department ofElectrical Engineering and Computer Science, University of Michigan, 4112 EECS Building, Arm Arbor, MI 48109-2122. Phone: (313) 764-4322, Fax (313) 763-1674.

Subscription information is available from:

Charles Reynolds, Customer Service Department, Gordon and Breach Science Publishers, P.O. Box 786, Cooper Station, New York, NY 10276. Phone: 1-800-545-8398, Fax: (212) 645-2459.

New PIARC Asphalt Report The Permanent International Association of Road Congresses (PIARC) has published a report on the use of porous asphalt.

The report provides information about: • how porous asphalt should be used to reduce

noise • where porous asphalt can be used • how long the specific functional qualities of porous

asphalt wearing courses will hold • how porous asphalt should be maintained • the effect porous asphalt has on safety.

The report (PIARC Ref. 08.01.B, Porous Asphalt) can be ordered from:

ANTRP 8 boulevard Vincent Gache F-44200 NANTES, FRANCE fax: +33 400095

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