road w orker s’ safety forum trials team trial of ... report... · innovative tapers were on the...

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Road Workers’ Safety Forum Trials Team

Trial of Innovative Taper LayoutTRL Test Track, 30th November 2006

CONTENTS

1. INTRODUCTION .......................................................................................................... 4

2. TRIAL DESCRIPTION AND METHOD .................................................................... 5

2.1. Background................................................................................................................. 5

2.2. Test Conditions ........................................................................................................... 6

3. RESULTS ........................................................................................................................ 7

3.1. Innovative taper: Layout 1 - Experimental setup assessment................................ 7

3.2. Innovative taper: Layout 2 - 150m taper with single intermediate cones ............. 9

3.3. Innovative taper: Layout 3 - 150m taper with two intermediate cones............... 11

3.4. Conventional taper: Layout 4 - 150m taper.......................................................... 13

3.5 Comparison of cone taper placement times ........................................................... 15

3.6. Subjective Assessments - Observer Questionnaire Results .................................. 16

3.7. Comments supplied by observers............................................................................ 17

4. SUMMARY ................................................................................................................. 19

5. CONCLUSION ............................................................................................................. 20

APPENDIX ............................................................................................................................ 21

1. INTRODUCTION

This report details the observations made at the track trial of an innovative lead taper layoutproposed to the Road Worker’s Safety Forum (RoWSaF)Trials Team by Carillion plc.

TRL were asked to observe and photographically record the trial on behalf of RoWSaF.

2. TRIAL DESCRIPTION AND METHOD

2.1 Background

This report details the observations of a trial of an innovative cone placement methodproposed by a member of staff at Carillion plc. The method reduces the number of conesrequired to complete a lane closure taper, reducing the time taken to place and retrieve andhence the exposure of road workers to traffic.

Figure 1: Conventional taper method and innovative taper method for a lane 3 closure

A schematic diagram of the innovative method is shown, for an offside (e.g. a lane 3) closure,in Figure 1 above. As can be seen, the innovative method involves placement of rows ofcones at specific points in the taper position. The idea behind this is to present a similarappearance of a “wall of cones” to the conventional method but with the following suggestedadvantages:

1) The novel method requires fewer cones compared to a conventional method.

2) The method requires less skill and time to line up compared to the conventionalmethod.

2.2 Test Conditions

Overview

The track trial was conducted on the “Large Loop” section of the TRL test track on November30th 2006. Simulated lane 3 closures were set up on two separate locations on the track. Theinnovative tapers were on the section adjacent to the “Long Straight” and a conventionalclosure on the motorway section on the other side of the loop. This way it was possible todirectly compare the conventional and innovative methods by a of drive-through observation.Additionally, static assessments of the closures were made by observers on foot. Both types ofassessment were made under daylight, dusk and night-time lighting conditions.

Data Collection

The dimensions of each taper were measured and recorded with a trundle wheel, and the timetaken to place each of the tapers was measured with a stopwatch.

All observers were given a questionnaire of qualitative questions to complete and a section fornotes. This questionnaire is included in the Appendix.

Photography and Video

Stills photography was used to record the appearance of the tapers from various angles, whilstthe drive-through observations were recorded by means of a video camera mounted in a LandRover Freelander vehicle. This vehicle was also used for the drive-through observations.Additional video footage was also taken from Carillion’s Traffic Management vehicle, aVolvo FL series truck.

3. RESULTS

3.1 Innovative taper: Layout 1 - Experimental setup assessment

The initial part of the trial involved experimental placement of the taper to finalise the layoutbefore timed runs and qualitative assessments took place. The taper was 100m in length andfeatured six rows of cones (varying between one and six cones) placed at 20 metre centres.This was followed by a longitudinal arrangement of cones placed at 18 metre centres.Sequentially flashing cone lamps were positioned on the ends of each line closest to therunning lanes. In order to make the taper as realistic as possible, signs to TSRGD diagram 610and 7105 were installed on the taper as prescribed in Chapter 8 of the Traffic Signs Manual .

0m

100m

80m

60m

40m

20m

196m

Figure 2: Innovative taper schematic diagram Layout 1

Nominal taper length 100m

Longitudinal cone separation 20m

Spacing of intermediate cones Not applicable

Total number of cones in taper 21

Measured taper length 104m

Time taken to put out taper (in daylight) Not recorded

Table 1:Measurements recorded for innovative taper Layout 1

Figure 3: Cone taper Layout 1

Figure 4: Cone taper Layout 1

Subsequent drive through inspections of this layout brought about a consensus thatintermediate cones were necessary, and subsequent innovative tapers featured extra cones toincrease their visual impact.

3.2 Innovative taper: Layout 2 - 150m taper with single intermediate cones

Due to the concerns raised after the observations made of Layout 1 above, it was decided thatintermediate cones should be placed to give the taper a more substantial appearance.

For Layout 2, the taper length was increased to a nominal length of 150m and singleintermediate cones were placed midway (i.e. 15 metres) between the rows of cones. Asbefore, each cone adjacent to the running lane was equipped with a sequentially flashing conelamp and relevant signing was installed. A longitudinal arrangement to 18m centres followedthe taper. The placement of this layout was timed.

0m

150m

120m

90m

60m

30m

246m

Figure 5: Innovative taper schematic diagram: Layout 2



Spacing of intermediate cones 15m



Time taken to put out taper (in daylight) 9 min 24 sec

Table 2: Measurements recorded for innovative taper Layout 2

Figure 6: Cone taper layout 2


3.3 Innovative taper: Layout 3 - 150m taper with two intermediate cones

Layout 3 was created to assess any potential increased benefit from an additional intermediatecone compared to Layout 2. An extra five cones (and hence five extra sequentially flashingcone lamps) were placed on the taper, meaning that the intermediate spacing was reduced to10m. All other dimensions were identical to those for Layout 2. A Longitudinal arrangementof cones to 18m centres followed the taper.

0m

150m

120m

90m

60m

30m

246m

Figure 8: Innovative taper schematic diagram: Layout 3



Spacing of intermediate cones 10m




Table 3: Measurements recorded for innovative taper layout 3

3.4 Layout 4 - 150m taper of conventional layout

Layout 4 was installed on the other side of the track from Layouts 1, 2 and 3. It was aconventional design as prescribed in Chapter 8 of the Traffic Signs Manual and served as areference for comparison to aid observers in their visual assessment of the innovative tapers.Additionally the placement of this taper was timed to aid comparison. As the track is a loop itwas easy to compare this conventional layout with the innovative method by circulating thetrack in a car.

0m

150m

246m

Figure 11: Standard 150m taper schematic diagram: Layout 4


Nominal longitudinal cone separation 3.0m

Spacing of intermediate cones Not applicable




Table 4: Measurements recorded for Layout 4

Figure 12: Standard 150m cone taper Layout 4

Figure 13: Standard 150m cone taper Layout 4

3.5 Comparison of cone taper placement times

Cone taper placement times are tabulated below:

Taper Time to put out taperLayout 2 (1 intermediate cone) 9 minutes 24 secLayout 3 (2 intermediate cones) 10 minutes 16 secLayout 4 (conventional Chapter 8) 18 minutes 47 sec

3.6 Subjective Assessments - Observer Questionnaire Results

Innovative taper trial & demonstration 30/11/06: daylight assessment

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60%

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90%

100%

Worse About the same Better

Comparison with standard taper

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Figure 14: Comparative assessment: daylight

Innovative taper trial & demonstration 30/11/06: Dusk

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%



(Sample size: 14)

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Figure 15: Subjective assessment: dusk

Innovative taper trial & demonstration 30/11/06: Darkness

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(Sample size: 14)

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Figure 16: Subjective assessment: darkness

3.7 Comments supplied by observers

Observers were invited to add general comments on the innovative taper arrangement. Thesecomments are tabulated below.

Experimental taper takes at least half the time to put out with the use of lesscones. Setting out the experimental taper is also a lot safer: No eying in ofthe taper. Operative is always very close or along side vehicle with very littleor no exposure to live traffic. Taking off the experimental taper means verylittle or no exposure to live traffic. Always working along side TM vehicle.Also, at end of taper, (first arrow) with the standard taper you would have tomove the last 20/25 cones out to a running lane (exposing the operative tolive traffic) than picking up from the well of the TM vehicle. With newexperimental taper, operatives don't have to do this again as they work withinthe close confines of the vehicle.

John Mercer -Carillion

No difference at night between the 10m and 15m spacing. I'd imagine thatthe sequential lighting provides best guidance for the driver.

Chrissie Falck-HA

A 15m gap appears to be too wide. With a 10m spacing, there is less of awall effect but this is virtually compensated by the row of cones.

Graham Coe -TRL

In my opinion, both tapers basically looked the same on approach. However,I don't know how much of that was due to the lamps.

Scott Rogers -Carillion

Personally, I feel that it would not make a difference to the public if thelamps are at 15m centres. From the operative’s point of view, I would preferthem at 15m centres because it would be less exposure for the us in the taper.I think that it is a brilliant idea and I would be happy to use it in the future.

Matthew Duff- Carillion

As an operative that will hopefully be using the new system, I feel that it isso much better - it takes half the time to put out and you spend less time onthe "live" side of the taper. For me, the 15m spacing was more than adequate.At 10m spacing, I had trouble lining the cones up. I would be more thanhappy to see this system come into play.

Darren Raine -Carillion

A standard taper take approximately 15 to 20 minutes to install with the coneplacer being exposed to live traffic the whole time. The innovative taper canbe installed in half that time and therefore exposure time is reduced by half.However because he always works from either the hard shoulder or centralreservation this exposure time is reduced even further.In terms of what the motoring public sees it does not look any different fromthe standard taper except for the fact that there are nearly 50% less cones.This reduces manual handling by nearly 50%.The trial was done initially with the spacing at 30 metres and then we infilled with additional cones and lamps which gave a 10 metre spacing.Having commenced the trial at 30 metre spacing's and then in filled it wasdecided to continue the trial at what was 10 metre spacing's. I fully acceptthe 9 metres is the norm and can see nothing which will be detrimental tocontinuing with 9 metre spacing's as this is what the operatives are used too.

Overall the visual effect was the same as a standard taper layout but with theadvantage of reduced exposure of the operative to traffic and reducing theeffects of manual handling.

BobWadsworthCarillion

Quicker, easier and safer. It does not call for an operative to walk the taper,with one foot in the live lane eyeing the line. This way of coning, in myoption. Should be implemented ASAP.

Ian Cole -Carillion

In darkness, the experimental taper looks less cluttered than the normal taper. John Mitchell- TRL

The taper tried was as good as a standard taper with cones at 3m centres froma visual viewpoint. The taper lamps now take the eye, and not the taperstructure The 'boxing out' to give taper shape is a good ,simple idea, thatoperatives can be easily trained on. The cone spacing's at 10m makes iteasier to eye in a straight taper.The issue of the 10 m spacing and how it ismeasured is to be considered further. 9m is standard. Therefore taper lengthsneed to be agreed. Because this taper uses less cones the single lane closurecan be installed by an ISU on a trunk road ( less than 30 cones) and a doublelane can be installed by an ISU on a 3lane plus carriageway(less than 60cones). This gives standardisation of tapers including emergency. I wouldrecommend that broad trials are carried out on this method to achieve greaterfeedback as I believe it has merit.

Don Gordon -Balfour BeattyInfrastructureServices

I see the final layout as a huge benefit to road workers with a 40% reductionin time exposed to danger, with less time spent standing on the carriageway,aligning cones.From the limited sample of road user runs on the test track the perceptionwas of little difference in the visual impact of the taper cones and lights. Thiswas certainly the perspective when travelling at 60 mph in the dark.Travelling in lane 1 the 10m gaps did not appear excessive or large enoughfor an errant motorist to try and get through. The small walls at right anglesto the carriageway would act as secondary delineators. Constructing the taperin 30m sections complete with operating lamps would ensure the road userhas maximum visibility of the taper if this makes sense

I would like to see a structured approach to further on road trials so we canmonitor road user response across a number of traffic conditions, such asvarying speeds, volumes and lane numbers. I like Bob’s idea of installing thefirst tapers on the M25 where cameras can monitor driver behaviour. I wouldalso suggest we engage with a professional driving organisation such as theinstitute of advance motorists to get valued road user feedback

Paul Fillis -Amey

I felt that as you got closer to the taper, it did appear to be slightly lesssubstantial. Having said that, does the appearance make that muchdifference?People who hit tapers have never said "it didn't look very substantial, so I hitit!" In fact they say the exact opposite "I never saw it". What we are trying todecide is does it do the same job of moving people out of the closed lane. Towhich I would answer yes.However I do have major concerns with the new style of taper: Cones at 10mcentres are not easy to install. Operatives work to 3m and 9m. White linesare 2m and 7m so every white line is 9m apart. TCB barrier is 3.2m inlength. There is approximately a 200mm overlap, which means theconnections on TCB are approx 3m apart. OBB is more difficult, butoperatives know from the well to rear wheel is again approx 3m. Therefore,why not leave the cone spacings at 9m centres? The new taper tookapproximately 10 minutes to install as opposed to a normal taper, whichtakes about 15minutes. If a normal taper takes 15m at 3m centres, a 9m-centred taper should take 5minutes. However installing the blocks takesconsiderably more time. Are these blocks of any value? Driving through theclosure I personally felt they had little effect (except the final one). Wheninstalling the blocks, operatives were not looking at the traffic they were toobusy looking down lining the bases side by side. This I believe is a potentialkiller. It is imperative operatives remain focused on the live traffic.It was also noted how long the IPV/TM vehicle remained in the line of fire"within the taper. A lot longer than a normal taper installation. The operativein the well was stood around waiting for a considerable period of time. As hehad to wait for the vehicle to slowly move along the lane. In a normal taperinstallation, once the cones have been dropped out the footwell, the operativewould assist in moving the cones out. The only real benefit of the blocks was

Craig Willsher- HA

to enable a consistently straight taper to be installed. Operatives have beendoing this for years. They are extremely skilled at it and it is second nature tothem. Eyeing in a cone is easy, once they have the line right.And ironically this new taper still meant 10 out of the 16 cones had to beeyed in. Therefore are the blocks needed?

During the hours of daylight the taper looked robust but the cone spacingleave cause for concern. At night time on the approach the taper lookedskeletal.I would have grave concerns regarding the (bar) use of cones at 18mintervals throughout the taper. Should third party enter the taper, as oftenhappens, they will in effect hit a number of straight barriers. The problemthen occurs as to where the cones will be dispersed to. My concern is thatsome of them could well be knocked over the centre reservation into a livelane with oncoming traffic. It goes without saying that the consequencescould be dire. As someone involved in day to day Traffic Management, Iwould be reluctant, to say the least, in recommending this procedure.

NormanKellock -Ringway

Approaching the tapers in the car, I could see no difference in visual impactbetween the standard Chapter 8 taper and the innovative taper, in daylight,dusk or darkness. As a passenger in the car, whilst parallel with the taper, Icould see that the cones were more sparsely spaced in the innovative taperthan the Chapter 8 taper. Would this encourage me to breach the taper?Personally, no.

Siggi Clark -TRL

4. SUMMARY

Comments about the innovative taper were generally positive. As can be seen from thegraphs, the majority felt that the appearance of the innovative taper was as good as or betterthan a conventional taper. The following points are worthy of note:

• The innovative taper arrangement requires less than half of the number of cones that aconventional taper requires.

• Installation times for the innovative taper were measured as between half and two-thirds of those for the conventional taper.

• Sequentially flashing cone lamps are invaluable to the safe operation of an innovativetaper.

• From a head-on view, the innovative taper looked very similar to the conventionalone, due in part to the sequentially flashing cone lamps.

• Acceptance from the attendant Traffic Management crew was very positive.• There was a tendency for the novel taper arrangement to look rather minimal from

steep angles when compared to the conventional arrangement. Whether or not this isan issue to motorists, who are passing the taper in an adjacent lane, is open to debate.

• It was proposed that the spacings of the cone walls be adjusted to suit the linemarkings to facilitate the placement of such a taper on a live road.

• One observer was concerned about the behaviour of rows of cones following impactfrom an errant vehicle.

5. CONCLUSIONS

The opinion of most observers at the track trial was that the appearance of the innovativetaper was at least as good as the standard Chapter 8 taper under daylight, dusk and darknessconditions.

The main areas for concern raised were:• Would the wider spacing of cones in the innovative taper at 10m centres encourage

drivers to breach the taper?• What would happen if the innovative taper was breached and a vehicle hit one of the

lateral rows of cones?

Representatives from three contractors at the trial (Amey, Carillion and Balfour BeattyInfrastructure Services) viewed the innovative taper very positively and expressed an interestto take the trial forward to an on road trial.

APPENDIX

Key for illustrations

Sequentially flashing cone lamps

Signs to 610 and 7105

Cones

Trial Map

Observer Questionnaire

Innovative taper track trial and demonstration 30th

November 2006

Name …………………………………………………………………………..

Organisation ………………………………………………………………….

a. DAYLIGHT trial & demonstration

In general terms, how do you rate the innovative taper compared with the standardtaper?


1 2 3 4 5

b. DUSK trial & demonstration



1 2 3 4 5

c. DARKNESS trial & demonstration



1 2 3 4 5

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