retro workshop

8/13/2019 Retro Workshop

1/16

TrafficSignRetroreflectivity

Workshop

July12,2011


2/16

Traffic Sign Retroreflectivity

as cs o gn

Retroreflectivit

&

New Sign

Requirements

1

Todays Speaker

, ,

Texas Transportation Institute,

Research Engineer

Head Operations & RoadwaySafety Division

Member of FHWA

Retroreflectivity Team

Member:

ASTM, TRB, NCUTCD, ITE

2

Todays Schedule

Start StopDescri tion

Time Time

9:30 10:00 Check in / Registration

10:00 10:15 Welcome / Participant Introductions

: : as c e rore ec v y g me s y oncep s

10:45 11:05 Texas MUTCD Requirements and compliance dates

11:05 11:45 Sign Retro Maintenance Methods

11:45 12:15 LUNCH

12:15 12:45 Retroreflectometer Demo / Discussions

Open Floor Discussions:

Practical Implementation of new requirements

12:45 2:00

Life Cycle Costs and cost reduction

Around the room, what have you already

implemented, what are you still planning, how well is it

working, and what does it cost?

Other items?

3

Welcome

Importance has increased

Not a part of any educational

curriculum

OTJ training

Your agency is now

responsible to maintain sign

retroreflectivity

4

Texas MUTCDs

http://www.txdot.gov/Current TX MUTCD

5

Background Information

6


3/16

Wh Do We Install Si ns?

Re uired b MUTCD?

NO

Engineering Decision?

YES!

Why?

To help drivers

7

Key Issue: Older Drivers

10.7 million drivers a e 70+ in 1990

+.

48% increase from 1990 to 2006

1990 8% of drivers were 70+ 2006 10.2% of drivers were 70+

Older driver population will continueto grow as baby-boomers age

8

TMUTCD Existing Reqs.

exas anua on n orm ra c on roDevices

Section 2A.06 Desi n of Si ns The basic requirements of a highway sign are that it

be legible to those for whom it is intended and thatit be understandable in time to ermit a ro erresponse. Desirable attributes include: High visibility by day and night; and

High legibility (adequately sized letters or symbols, and as or egen or qu c compre ens on y a roa userapproaching a sign).

9

TMUTCD Sign Maintenance

TMUTCD Section 2A.22 Maintenance

Maintenance activities should consider properposition, cleanliness, legibility, and daytime andni htt ime visibili t see Section 2A.09 . Dama edor deteriorated signs should be replaced.

To assure adequate maintenance, a schedule for, ,

replacing signs should be established.

Ste s should be taken to see that weeds, trees,shrubbery, and construction, maintenance, andutility materials and equipment do not obscure the

face of any sign.

10

Night Travel and Crashes

11

Nighttime Driving

Many cues availableMany cues available

Driver task relatively easyDriver task relatively easy

Few cues remainFew cues remain

Task more difficultTask more difficult

RetroreflectivityRetroreflectivity provides nighttime guidanceprovides nighttime guidance

12


4/16

Why Create Minimums?

Daytime

Nighttime

13

Typical Outdoor Durability Testing

T e III

45 degree south facing

le

ctivity

Retrorefl

Type II

Type I

0 10 20 30 40 50 60 70 80Age (months)

14

Retroreflectivity

Concepts

15

RETROreflection

16

Retroreflection

of light returned froma sign versus theamount hitting thesign

efficiency of a material

Light OUT of sign

Light INTO sign= Retroreflectivity

17

Retroreflective Elements

Glass s heres and microsized risms arethe current technologies used to make sign

materials retroreflective

The light is returned to the source in a cone

shaped pattern

18


5/16

Sign Sheeting Materials

Engineering Grade

Hi-Intensity

Beaded

Microprismatic

19

Sheetin T es

(Type III e.g. High Intensity)

20

Technical Terms

Retroreflective Si n(RAcd/lx/m

2)Luminance(cd/m2)

Illuminance (lx)

21

Basic Angles of Retroreflectivity

Observation An le Where in the coneis the measurement made (from the lightsource).

Entrance An le What is the orientationof the sign or pavement marking (is fromthe light source)

22

Key Geometry Angles

Observation an leObservation an le Between source and receptorBetween source and receptor

(red and blue lines)(red and blue lines)

PerpendicularPerpendicular

to s gnto s gn

Entrance angle (Entrance angle ())Between source andBetween source and

target axistarget axis(blue and green lines)(blue and green lines)

23

Sheeting Specification Geometry

24


6/16

Rotational Sensitivit

25

Rotation Marks

Microprismatic sheeting

Retroreflectivit can var with

rotation

Some rismatic sheetin hasorientation arrows

,

cutting, and fabricating signs

26

Rotational Sensitivit

y

oreflectivi

Retr

Minimum

Retro

0 degrees 45 degrees 90 degrees

27 28

Questions

29

MUTCD Sign Retroreflectivity

Maintenance Requirements

New Requirements

30


7/16

Congressional Legislation

1993 DOT A ro riations Act1993 DOT A ro riations Act

The Secretary of

revise the MUTCD to

include a standard for aminimum level of

maintained for traffic signs and

avement markin s which a l to all

roads open to public travel.

31

Final Rule

Published on Dec 21, 2007

, .

Edition of the MUTCD

Effective Jan 22, 2008

32

New MUTCD Language.

an ar :

Public agencies or officials having jurisdiction

s a use an assessmen or managemen

method that is designed to maintain sign

levels in Table 2A-3

33

New MUTCD Language.

Su ort:

Compliance is achieved by having a method

in lace and usin the method to maintain the

minimum levels established in Table 2A-3.

Provided that a method is being used, an

agency would be in compliance even if there

are some individual signs that do not meet the

.

34

New MUTCD Language

One or more of the following assessment

or management methods should be used

Ex ected Si n Life

Inspection

Calibration Si ns

Blanket Replacement

Control Signs

Comparison Panels

Future Method BasedOn Engr. Study

Parameters

Measured Si n Retro

Combination Of Any

35

New MUTCD Table 2A.3Minimum Maintained Retroreflectivity Levels

36


8/16

What do the numbers look like?

c ures o no represen re rore ec v y we

37

Exempt Signs

Parking/Standing/Stopping

Walking/Hitchhiking

Adopt-A-Highway

Blue or BrownBackgrounds

Exclusive Use of Bikesor Peds

Note: Must still meet other

requirements in MUTCD

(inspections,,

etc,)

38

Clarification

fluorescent yellow -- > yellow

- --

fluorescent orange -- > orange

39

Compliance Dates

s a s an mp emen me o s

January, 2012

Replace identified regulatory, warning, ground-mounted guide signs (except street-name)

anuary,

Replace identified street name & overhead guidesigns

January, 2018

40

Summary of New Language

Public a encies or officials havin urisdiction shall usean assessment or management method that isdesigned to maintain sign retroreflectivity at or abovethe minimum levels in Table 2A-3

Compliance is achieved by having a method in place

established in Table 2A-3. Provided that a method isbeing used, an agency would be in compliance even

ere are some n v ua s gns a o no meethe levels at a particular point in time.

41

Can you see the sign?

42


9/16

Questions

43

MUTCD Si n Maintenance

Methods

44

Can we decide to replace signs based on

45

- - -- - -

46

MUTCD Methods

Measured retroreflectivity

Expected sign life

Blanket replacement

Control signs

Combination of methodswww.fhwa.dot.gov/retro

47

Method: Visual Assessment

Com arison anels rocedure or

3 Techniques:

Calibration signs procedure, or

48


10/16


panels

Clipped to sign - viewed from distance

49

Comparison Panels

have a retroreflectivity level

the MUTCD

done at night

These panels have retroreflectivity

levels at the levels in the MUTCD

minimum retroreflectivity table

Comparison Panel Procedure

50

Source of Comparison Panels

,

find in-service signs near the minimum

.

from service and cut into smaller pieces.

scrap yard.

very enn son us announce

availability comparison panels.


51

Field Procedure


52


Calibrate eyes with calibration signs

Calibration

minimum retro

va ua e s gns

compared to

ca ra on s gns

53

Calibration Signs

have a retroreflectivity

designated in the

The inspection has to be

Calibrated Signs Procedure

54


11/16

Source of Calibration Signs

With a retroreflectometer an a enc canfind in-service signs near the minimumlevels. These signs can be removedfrom service and stored until nighttimesign inspections commence.

An agency can also look through theirscrap yard for representative signs.

Avery Dennison just announced

availability comparison panels.


55

Field Procedure

These signs have retroreflectivity

levels at the levels in the MUTCD

l lm n m um re r ore l ec v y a le


56

Visual Inspection Method:

57

Overview

With this method a SUV or truck has to be used

with specific headlamps (described later) and

the inspector needs to be at least 60 years old.

The inspection occurs at highway speeds.

No calibration signs or comparison panels are

needed.

This method simulates the conditions of the

research which FHWA used as a foundation for

the minimum retroreflectivity levels.

Consistent Parameter Procedure

58

Field Technique

Preferable to use a two erson crew. Must have a SUV, pick-up, or similar vehicle

with VOA style headlamps.

Driver can be any age but inspector needs tobe at least 60 years old.

nspec on occurs a g way spee s.

Inspector concentrates on judging sign.

Example: adequate, marginal, poor (replace)

Driver concentrates on drivin safel .

Consistent Parameter Procedure

59

Method: Measure Sign Retro

Use a portable instrument

Receive proper training

Compare readings to minimum values

60


12/16

Overview

This method includes si nretroreflectivity measurements of in-service signs

The measurements are made with

devices similar to cordless drills The measurement devices must be in

contact with the sign face

The measurements need to beperiodically repeated (e.g., annually orevery other year)

61

Examples of Sign Retroreflectometers

on ac

Devices:

Model GR3(Delta)

Model 922(Gamma Scientific)

Non-ContactExperimental concept,

but NOT etavailable.

Devices:

l l

SMARTS Van

62

Field Procedure

Measure each color that is retroreflective

Multiple measurements should be made

to compute an average

A measurement protocol should be

developed

An extension pole or ladder will be

needed

63

64

64

Measurement Protocol

,may require a minimum of

as shown to the left

measurements would be

condition of the sign

65

Taking Measurements

66

66


13/16

Method: Expected Sign Life

Find the life of the sheeting type in your area

Re lacement based on ex ected life for

individual signs

67

Indicating Sign Age

when fabricated or installed

68

Determining Sign Life

Build and use a weathering rack

like the one shown

-

Use warranty information from

sheeting company

pec y s gn e

Measure existing signs with

known install date and compare to

min level

Use weathering data or nearbyurisdictions weatherin data

69

Using Warranty Information

Predicted si n a e could be rovided in a

warranty by sheeting manufacturers.

T ical warranties not t icall based on

minimum retroreflectivity levels

Agencies could develop specifications with

warranties based on minimum retroreflectivity

levels

Example: Warranty Type III sheeting for 15 years in

accordance to Table 2A-3 of the MUTCD

70

Weathering Racks at TTI

71

Method: Blanket Replacement

All signs in an area/corridor are replaced at the

same time at specified intervals

Specified intervals could be set based on

expected sign life

Some existing blanket sign replacement policies

exist using 10-12 years for Beaded High-

72


14/16

Blanket Replacement

Divide a enc into Exam le

areas/corridors or zones

Relate number of areas toReplaceReplace

7th7thyearyear

replacement cycle

Replace all signs in an

this areathis areaduring 1stduring 1st

yearyeararea/ corridor each

replacement cycle

3rd3rdyearyear

yearyear

10 yr life, 10 areas

Annual replacement in each

City of Tempe AZ Maintenance Zones

73

Method: Control Signs

Sign life is estimated using a subset of signs

representing an agencys inventory.

Subset of signs is the control signs

--

maintenance yard.

Agency monitors control Example of Control Signssigns to estimate condition

of all their signs.

Periodically measure

retroreflectivity of control

.

74

MUTCD Methods


Expected sign life

Blanket replacement

Control signs

Combination of methods

www.fhwa.dot.gov/retro

75

Method: Other Options

Flexibility is provided for

future advancements in

technology and methods

that have not been fully

developed

Must be based on an

engineering study

76

Future Technologies

Mobile sign retroreflective

measurement technology

e ng eve ope y a

least 3 different companies

that measures pavement

highway speeds

77

MUTCD Methods


Expected sign life

Blanket replacement

Control signs

Combination of methodswww.fhwa.dot.gov/retro

78


15/16

NCHRP Survey Participants

Survey conducted May 2011

Included 9 cities, 15 counties, 16 DOTs, and 9 others

79

Agency Method Selection

MUTCD MethodsPrimary Sign

Replacement MethodSecondary or

Support Method

Measured Retro. 2 0

Expected Sign Life 17 16Blanket Replacement 7 4

Control Signs 2 10

Note: Table only includes agencies that operate and maintain

roadways that are open to the public

80

Summary: Methods Allowed

Visual Ni httime Ins ection Calibration Signs

Comparison Panels

Consistent Parameters

Measured Sign Retro

Blanket Replacement

Future Method Based On Engr. Study

81

ona n orma on

82

More Information

ATSSA www.retroreflectivity.net

Primer on retroreflectivity

Common questions

FHWA fhwa.dot.gov/retro

Summar Brochure

Final Rule

Newsletter Articles

83

FHWA Supporting Material

www.fhwa.dot.gov/retrowww.fhwa.dot.gov/retro

-

s

Research Reports

84


16/16

85

Thank You

au . ar son

[email protected]

- -

86

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