Great Plains Waste Management Conference April 18, 2013 MUTCD MUTCD. Why Do We Install Signs? MUTCD

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1 Great Plains Waste Management Conference April 18, 2013 Retroreflectivity Assessment and Management Methods Presented by Don Neary Nebraska LTAP Starting at age 20, the amount of light needed to see an object the same way doubles every 13 years Amount of Light Needed Age MUTCD Manual on Uniform Traffic Control Devices The 2009 MUTCD is the current National Standard for all traffic control devices installed on all roads that are open to public travel. MUTCD Section 2A.06 Design of Signs The basic requirements of a highway sign are: That it be legible to those for whom it is intended, and That it be understandable in time to permit a proper response Why Do We Install Signs? Required by MUTCD? NO Engineering Decision? YES! Why? To provide orderly movement of all road users (including older drivers) MUTCD Section 2A.06 Design of Signs (Con t.) Desirable attributes include: High visibility by day and night, and High legibility Adequately sized letters or symbols, and A short legend for quick comprehension by a road user approaching a sign. 1

2 MUTCD Section 1A.07 Responsibility for Traffic Control Devices New MUTCD Table 2A.3 Minimum Maintained Retroreflectivity Levels The responsibility for the design, placement, operation, maintenance, and uniformity of traffic control devices shall rest with the public agency or the official having jurisdiction Section 2A.08 Maintaining Minimum Retroreflectivity Public agencies or officials having jurisdiction shall: Use an assessment or management method that is designed to maintain sign retroreflectivity at or above the minimum levels in Table 2A-3 New Traffic Sign Maintenance Requirements with a narrated explanation MUTCD Table 2A.3 New MUTCD Table 2A.3 Minimum Maintained Retroreflectivity Levels Sign Color White on Green Black on Yellow or Black on Orange Sheeting Type (ASTM D ) Beaded Sheeting Prismatic Sheeting I II III III, IV, VI, VII, VIII, IX, X W* G 7 W* G 7 W* G 15 W* G 25 W 120; G 15 W 250; G 25 Additional Criteria Overhead Groundmounted Y*; O* Y 50; O 50 Y*; O* Y 75; O 75 White on Red W 35; R 7 Black on White W 50 The minimum maintained retroreflectivity levels shown in this table are in units of cd/lx/m 2 measured at an observation angle of 0.2 and an entrance angle of For text and fine symbol signs measuring at least 1200 mm (48 in) and for all sizes of bold symbol signs For text and fine symbol signs measuring less than 1200 mm (48 in) Minimum Sign Contrast Ratio 3:1 (white retroreflectivity red retroreflectivity) * This sheeting type should not be used for this color for this application. Types that meet Minimums NO NO NO NO NO 2

3 MUTCD Sign Maintenance Section 2A.22 Maintenance Maintenance activities should consider: Proper position Cleanliness Legibility Daytime and nighttime visibility (see Section 2A.07) The uniformity of the sign design shall be maintained without any decrease in visibility, legibility, or driver comprehension during either daytime or nighttime conditions. MUTCD Sign Maintenance Section 2A.22 Maintenance To assure adequate maintenance: A schedule for inspecting (both day and night) Cleaning, and replacing signs, gates, and object markers should be established Employees of highway, law enforcement, and other public agencies should be: Encouraged to report any damaged, deteriorated, or obscured signs, gates, or object markers at the first opportunity MUTCD Sign Maintenance Section 2A.22 Maintenance Steps should be taken to see that weeds, trees, shrubbery, construction, maintenance, and utility materials and equipment do not obscure the face of any sign A regular schedule of replacement of lighting elements for illuminated signs should be maintained MUTCD Sign Maintenance More Than Just Retroreflectivity MUTCD does not state how frequently signs should be inspected once a year, once every two years, etc. Conducting nighttime inspections once per year is considered reasonable Source: NCHRP Synthesis 431 3

4 Nighttime Driving Day/Night Example Daytime Many cues available Driver task relatively easy Nighttime Few cues remain Task more difficult Retroreflectivity provides nighttime guidance 22 Retroreflective Signs Daytime signing here is complementary Retroreflectivity Concepts What does it mean? Nighttime signing here is necessary 20 Day/Night Example Retroreflection (Informal Definition) A ratio of the amount of light returned from a sign versus the amount hitting the sign A way to measure the efficiency of a material Light OUT of sign Light INTO sign = Retroreflectivity 4

5 Retroreflection Retroreflectivity Assessment and Management Methods On May 14, 2012, a final rule was published in the Federal Register, revising Table I-2 in the Introduction of the 2009 MUTCD to modify the compliance dates for the minimum maintained sign retroreflectivity standard. Over time, the retroreflectivity of a sign decreases, making it less visible for nighttime drivers. That rulemaking extended the compliance date for implementation and continued use of an assessment or management method that is designed to maintain traffic sign retroreflectivity at or above the established minimum levels to June 13, 2014 and refined the compliance date to only apply to regulatory and warning signs, and not others. Retroreflectivity Assessment and Management Methods Section 2A.08, 2009 MUTCD: Public agencies or officials having jurisdiction shall use an assessment or management method that is designed to maintain sign retroreflectivity at or above the minimum levels in Table 2A-3. Retroreflectivity Assessment and Management Methods Option: (Sec. 2A.08) Highway agencies may exclude the following signs from the retroreflectivity maintenance guidelines described in this Section: A. Parking, Standing, and Stopping signs (R7 and R8 series) B. Walking/Hitchhiking/Crossing signs (R9 series, R10-1 through R10-4b) C. Acknowledgment signs D. All signs with blue or brown backgrounds E. Bikeway signs that are intended for exclusive use by bicyclists or pedestrians Retroreflectivity Assessment and Management Methods A. Visual Nighttime Inspection B. Measured Sign Retroreflectivity C. Expected Sign Life D. Blanket Replacement E. Control Signs F. Other Methods developed based on engineering studies can be used Additional information about these methods is contained in the 2007 Edition of FHWA s Maintaining Traffic Sign Retroreflectivity Visual Assessment Methods A. Nighttime Inspections One or more of the following methods should be used to support the visual inspections: Comparison Panels Procedure Consistent Parameters Procedure 5

6 Visual Inspection Requirements Trained inspector Having done visual nighttime inspections does not necessarily equate training* Nighttime inspection Need to tie to minimum values by using one of the following techniques: Comparison panels procedure, or Calibration signs procedure, or Consistent parameters procedure *Source: NCHRP Synthesis 431 Field Procedure Visual Inspection Method: Comparison Panels Comparison panels must have a retroreflectivity level at least that designated in the MUTCD per table 2A-3 The procedure must be done at night These panels have retroreflectivity levels at the levels in the MUTCD minimum retroreflectivity table Overview Any vehicle, any inspector age is OK The initial inspection occurs at highway speeds with low beams When a marginal sign is spotted, Safely pull over to inspect the sign, Install comparison panel on the sign, Evaluate from at least 25 feet, Hold a flashlight near inspector s ear, Is the sign at least as reflective as the comparison panel? Source of Comparison Panels With a retroreflectometer, an agency can find inservice signs near the minimum levels These signs can be removed from service and cut into smaller pieces An agency can also look through their scrap yard Panels can be made using the method developed by Cornell Local Roads Program 6

7 Pass or Fail? Completed Retroreflectivity Testing Kit Pass or Fail? Pass or Fail? Pass or Fail? Comparison Panel Checklist Be well rested Select inspection vehicle and have headlamps aimed Select inspection routes (both directions) Prepare inspection forms (example shown later) Have sign list if available (for each inspection route, a list of signs you expect to see, in order of the direction of travel) 7

8 Comparison Panel Checklist Con t. Clip board, pen lights, dash cam, tape recorder, laptop, Comparison panels Ladder Retroreflective garments (vest or jacket) Flashing lights for safety when installing comparison panel (beacon) Cannot start in earnest until complete darkness Calibration Signs Calibration signs must have a retroreflectivity level at least that designated in the MUTCD per table 2A-3 The inspection has to be done at night Visual Inspection Method : Source of Calibration Signs With a retroreflectometer, an agency can find in-service signs near the minimum levels These signs can be removed from service and stored until nighttime sign inspections commence An agency can also look through their scrap yard for representative signs Retroreflectivity Compliance Kits are available Overview Any vehicle, any inspector age is OK Before leaving the maintenance yard, the inspectors visually inspect a set of representative signs in an effort to calibrate their eyes before starting the nighttime inspections The calibration signs should be viewed at distances from 600 feet to 100 feet Use low beams The inspection occurs at highway speeds These signs have retroreflectivity levels at the levels in the MUTCD minimum retroreflectivity table Field Procedure 8

9 Field Procedure Use the same vehicle that will be used during the visual inspection View the calibration signs from the inspection vehicle at distances from 600 feet to100 feet before leaving the maintenance yard / parking lot During the visual inspection, look for signs less bright than the calibration signs Mark these signs for replacement May include a route that allows inspector to review calibration signs during inspection Visual Inspection Method: Checklist Be well rested Select inspection vehicle and have headlamps aimed Select inspection routes (both directions) Prepare inspection forms (example shown later) 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 of age 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 Checklist Con t. Have sign list if available For each inspection route, a list of signs you expect to see, in order of the direction of travel Clip board, pen lights, dash cam, tape recorder, laptop, Cannot start in earnest until complete darkness View calibration signs before starting your inspection routes Field Technique Preferable to use a two person crew Must have a SUV, pick-up, or similar vehicle with VOA (Visually Optically Aimed) style headlamps Driver can be any age but inspector needs to be at least 60 years old Inspection occurs at highway speeds Inspector concentrates on judging sign retroreflectivity Example: adequate, marginal, poor (replace) Driver concentrates on driving safely 9

10 Headlamp Identification Common Visual Inspection Features Aim inspection vehicle headlamps (take to certified auto mechanic) Two-person crew works best Having an inventory is preferred Use low-beam headlamps Have evaluation form and criteria Example: good or bad (replace) Conduct evaluations at roadway speed Consistent Parameter Procedure Checklist Inspector and driver need to be well rested Have SUV/ Truck vehicle with VOA headlamps aimed properly Have routes selected Prepare enough inspection forms Have sign list if available Visual Inspection Tips It is preferred to have a list of the signs along the inspection route Adds consistency to the inspections Reduced need for writing during inspection Only need a score for each sign such as: good, marginal, replace Provides documentation that the inspections were conducted --- just in case! Allows identification of missing signs Consistent Parameter Procedure Checklist Con t. Clip board, pen lights, dash cam, tape recorder, laptop, Be fueled up Cannot start in earnest until complete darkness Remember to evaluate both colors of signs with two retroreflective colors (white on green, white on red, etc.) Date: Inspector: Sign List Example Sign Retroreflectivity Inspection Form Route start point: Route end point: Sign Sign Odom. RETROREFLECTIVITY Description Color Reading Good Marginal Replace Stop Red 0.1 Route Mkr Wht 0.2 Spd Lmt Wht

11 Visual Nighttime Inspection The visual nighttime inspection method was the second most selected method The key is conducting sign inspections during the time of the year when there is less daylight In rural areas, a night session would last approximately 3 to 5 hours Covering about 100 miles of one direction of a roadway Management Method: B. Measured Sign Retroreflectivity Sign retroreflectivity is measured using a retroreflectometer Signs with retroreflectivity below the minimum levels should be replaced Retroreflectivity Assessment and Management Methods One or more of the following assessment or management methods should be used (Guidance Statement Section 2A.08) A. Visual Nighttime Inspection 1. Comparison Panels 2. Calibration Signs 3. Consistent Parameters B. Measured Sign Retroreflectivity C. Expected Sign Life Measured Sign Retroreflectivity Measured retroreflectivity was the least selected method Most agencies did not consider it as a primary method for maintaining minimum sign retroreflectivity High cost for a retroreflectometer and for the considerable demand on labor and time Retroreflectivity Assessment and Management Methods Con t. D. Blanket Replacement E. Control Signs F. Other Methods developed based on engineering studies can be used Additional information about these methods is contained in the 2007 Edition of FHWA s Maintaining Traffic Sign Retroreflectivity Management Method: C. Expected Sign Life When signs are installed, the installation date is labeled or recorded so that the age of a sign is known The age of the sign is compared to the expected sign life The expected sign life is based on the experience of sign retroreflectivity degradation in a geographic area compared to the minimum levels Signs older than the expected life should be replaced 11

12 Expected Sign Life Expected sign life method was found to be used the most often Recommended that agencies strongly consider some type of expected sign life system to better manage resources and track sign data Management Method: D. Blanket Replacement All signs in an area/corridor, or of a given type, should be replaced at specified intervals This eliminates the need to assess retroreflectivity or track the life of individual signs The replacement interval is based on the expected sign life, compared to the minimum levels, for the shortest-life material used on the affected signs Expected Sign Life Con t Two basic ways that the expected sign life method is used: #1 - Build an inventory, assess the signs condition (especially retroreflectivity) Then develop an estimate for the remaining number of years that the signs could be in service Blanket Replacement Blanket replacement was the third most selected method Simple and easy to implement Most common concern was the potential waste of labor and materials that came from replacing adequate signs To reduce waste, establish replacement corridors with replacement cycles of years Expected Sign Life Con t #2 - Install date stickers on the signs Management Method: E. Control Signs Replacement of signs in the field is based on the performance of a sample of control signs The control signs might be a small sample located in a maintenance yard or a sample of signs in the field The control signs are monitored to determined the end of the retroreflective life for the associated signs All field signs represented by the control sample should be replaced before the retroreflectivity levels of the control sample reach the minimum level 12

13 Control Signs The use of control signs was the fourth most selected method Did not thoroughly investigate this method because it requires both A retroreflectometer for collecting measurements, and A system for managing sign data This method may take time to implement but it does have advantages Management Method: E. Control Signs Example Control Signs Con t Setup a sign inventory system to manage and track individual signs Each year measure the retroreflectivity of the oldest signs for each sign color The sign inventory system is used to determine the locations of the oldest signs on the roadway Management Method: F. Other Methods Other methods developed based on engineering studies can be used Additional information about these methods is contained in the 2007 Edition of FHWA s Maintaining Traffic Sign Retroreflectivity. Control Signs Con t The oldest signs served as the control sample If these signs were still meeting the minimum levels, then the newer signs should also be adequate Myths and Other FAQs A hand-held retroreflectometer is required to meet the new MUTCD requirements Not true for all methods However, there are methods that do require the use of a retroreflectometer There are alternatives to purchasing retroreflectometers 13

14 Myths and Other FAQs Engineering grade material is not allowed now For some sign types, this is true Engineering grade sheeting (or ASTM Type I material) is not allowed for yellow or orange warning signs and for the legend on guide signs and street name signs MUTCD Table 2A.3 Myths and Other FAQs Retroreflectivity can be assessed by nighttime photos As FHWA explains in its literature, using photos of signs is not an acceptable method to judge retroreflectivity The amount of light and the proximity of the light to the camera can make a perfectly good sign look bad or vice versa Myths and Other FAQs A computer inventory is required No sign inventory is required However, there are many benefits of having a sign inventory as described in the report Additional Considerations Will the methods we reviewed today be effective in all conditions? Can you think of some other field methods that might be used to evaluate traffic sign retroreflectivity? Myths and Other FAQs Sign Conditions If you implement the blanket replacement method you can forgo routine maintenance Not true There are many other aspects of signing that need to be maintained besides retroreflectivity For examples, there are knockdowns, vandalism, and vegetation that all need constant maintenance to ensure that the signs perform as intended 14

15 Rural vs Urban Areas The minimum retroreflectivity levels in the MUTCD are based on Older drivers vision Sign recognition and legibility Rural areas without background complexity Your job is the most important part of making this new regulation successful What happens in urban areas? Increase safety Increase nighttime visibility 88 Can you see the sign? Resources Nebraska LTAP Center NIRMA Retroreflectometers for loan Methods for Maintaining Traffic Sign Retroreflectivity, 2007 FHWA-HRT FHWA fhwa.dot.gov/retro ATSSA 15