Signal Spotlight: New Resource: Decision-Making Guide for Signal Phasing

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New Resource: Decision-Making Guide for Signal Phasing

Earlier this year, the TRB released NCHRP Web-Only Document 284: Decision-Making Guide for Traffic Signal Phasing. The document outlines the existing best practices on signal phasing along with the results of NCHRP Project 03-118, under which researchers developed new safety performance functions (SPFs) and crash modification factors (CMFs) for various left-turn phasing scenarios at the intersection level. The document covers guidance on left-turn phasing mode, right-turn phasing mode, phase sequence and pedestrian phasing.

Five Key Takeaways:

According to the results of a survey conducted as part of the study, only 29% of responding agencies reported having formal policies, guidelines or procedures for selecting the most appropriate phasing for a signalized intersection.

The CTDOT Traffic Control Signal Design Manual outlines the acceptable options for left-turn phasing along with some general requirements for implementation. The Decision-Making Guide for Signal Phasing provides additional guidance relating to safety and operational considerations, as well as other unique contexts, such as transitways and separated bike lanes. Various alternatives to left-turn phasing are also provided.

The Guide provides comprehensive, clear and concise guidelines for decisions related to traffic signal phasing, but it is not intended to serve as a regulatory standard or requirement.

While the Guide provides useful information for engineers to select the most appropriate signal phasing, engineering judgment should be used. It is also important to coordinate with CTDOT to ensure that all Connecticut design standards are met.

According to a literature review conducted as part of the study, no known research indicates a safety or operational benefit to matching left turn phasing mode on opposing approaches.

Some agencies require that the same left-turn phasing mode is used on opposing approaches, but in some cases, it may be more appropriate to allow permissive turns on one of the approaches. The Guide also discusses situations in which a variable mode may be appropriate.

The pedestrian phasing information presented in the Guide discusses factors to consider for concurrent vs. exclusive phasing, LPI, detection, pedestrian prohibitions, and two-phase crossings.

The information presented in the guide should prove useful for refining pedestrian crossing designs; however, it is important for the design engineer to reference the CTDOT Traffic Control Signal Design Manual and the associated Interim Pedestrian Considerations and Pedestrian Signal Design – Technical Info documents. CTDOT has clearly defined policies and standards on pedestrian signal phasing and design.

The research conducted as part of the study produced new safety performance functions and crash modification factors for left-turn phasing modes.

The Guide provides a table of crash modification factors as well as a description of a methodology for combining delay and crash costs to conduct cost-benefit analyses for various phasing alternatives.

If you have traffic signal systems questions, please contact: Theresa Schwartz, P.E.,
P.T.O.E. – Traffic Signal Circuit Rider (860) 486-4535 or theresa.schwartz@uconn.edu.

Resources:

Decision-Making Guide for Traffic Signal Phasing: http://www.trb.org/main/blurbs/181114.aspx

CTDOT Traffic Control Signal Design Manual and Related Content:
https://portal.ct.gov/DOT/Traffic-Engineering/Traffic-Control-Signal-Design-Manual

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Safety Matters: Teen Driver Safety

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Teen Driver Safety

National Teen Driver Safety Week is October 18-24 this year. The National Highway Traffic Safety Administration (NHTSA) has good reason to highlight teen driver safety, as motor vehicle crashes are the leading cause of death for teens, ages 15-18 years old, in the United States. Teen drivers are two-and-a-half times more likely to engage in one or more potentially risky behaviors when driving with another teen in the vehicle, compared to when driving alone, according to the results of a study analyzed by NHTSA. According to that same study, the risk increases with the addition of teen passengers.

In Connecticut, in an effort to reduce teen fatalities on the roadways, graduated license laws were put into effect in 2008. The stricter rules for teen drivers have resulted in teen car crash fatalities dropping from an average of 18 per year in 2001-2007 to seven per year in 2009-2016, according to a 2018 press release from the Department of Motor Vehicles. Unfortunately, teen drivers and passengers are still dying on our roads. Much like any other law, the graduated license laws are only effective when followed.

So how can we help keep teens in our community safe? One of the best ways, especially if one has a teen driver or soon-to-be driver in their life, is to be a good role model. By following the rules of the road, wearing a seatbelt, focusing on driving and not being distracted we model safe driving behavior. Talking to teens about safe driving and the responsibility of being behind the wheel is also paramount to their understanding of the potentially fatal consequence of a bad decision. Inexperience, speeding, lack of seatbelt use, impaired driving and distracted driving are all culprits of increased risk to teens in vehicles. Most of these have a solution though; encourage teens in your life to make the right choices as a driver and as a passenger.

For more information and assistance with local road safety in your community, contact Melissa Evans, Safety Circuit Rider, at melissa.evans@uconn.edu.

Resources:

“Teen Driver Fatal Crashes on Sharp Decline,” DMV News, August 1, 2018, Connecticut Department of Motor Vehicles:
https://portal.ct.gov/DMV/News-and-Publications/News-and-Publications/Teen-Driver-Fatal-Crashes-on-Sharp-Decline-as-State-Marks-10th-Anniversary-of-Tougher-Driving-Laws-f

Teen Driving, National Highway Traffic Safety Administration: https://www.nhtsa.gov/road-safety/teen-driving

Teen Drivers: Get the Facts, Centers for Disease Control and Prevention:
https://www.cdc.gov/motorvehiclesafety/teen_drivers/teendrivers_factsheet.html

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Warren’s Words of Wisdom: Hot Stick Voltage Detectors — A False Sense of Safety?

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Hot Stick Voltage Detectors — A False Sense of Safety?

There are several versions of voltage detectors I’ve seen firefighters and public works folks have purchased. Then they’ve asked me what I think of them. I have always told them the only 100% way that I can guarantee the power is shut off and safe for a first responder or public works to do anything (touching, pushing, rescuing) is when the utility has shown up and done whatever they need to do to make the situation safe. That means the utility has opened taps, fuses, grounded wires or whatever they have needed to do to tell you that you can safely do your work.

In a storm or emergency, many justify not waiting for the utility and take matters into their own hands, and sometimes rely on the voltage detectors as the all clear to do what they need to do. Let me point a few things out.

Depending on the conductor, electricity travels at something less than 186,000 miles/second but still faster than your kids attacking the dessert buffet at Foxwoods. So let’s say you walk up to down wire with a tree on it, hold out the hot stick, and nothing happens. Before you can turn around and say, “It’s safe,” a recloser 2 miles away resets and re-energizes the line to 23,000 volts; that takes like 0.0000038 seconds.

But maybe there wasn’t a recloser, and you did the road opening without incident—great job! I bet the success that time gave you confidence to do the same approach the next time and maybe another 100 times. Sorry, but in my opinion, you got lucky…until the day you didn’t.

As a certified safety professional, I believe any approach to a situation with electrical wires must have direct involvement with your local utility to ensure you will be as safe as possible. Any efforts to perform work without the direct involvement of the utility people is a risk. I personally would not risk my life using a hot stick voltage detector as a go/no-go to remove a tree with wires or to open a car with wires on it. If you do have one of these devices, please follow the manufacturer’s instructions for maintaining and testing.

Do hot stick voltage detectors have a role in keeping first responders and public works safe? Yes, they do, by alerting them to energized down wires. However, to utility linemen, any wire that is not “dead and grounded” will be treated as “hot,” meaning you do not trust it to be safe until it is and is handled with rubber gloves and sleeves. A hot stick gives you an instantaneous reading on the wire. That doesn’t mean the wire can’t be energized again; it just means at that instant the wire is hot or not.  Are you willing to risk a life that the wire will stay that way?

You didn’t know that, did ya?

Seat belts became mandatory in 1968, though then they were only lap belts. I had a driver’s license (in Tennessee you could get a Learners Permit at age 15 or get married at age 14, your choice), but I couldn’t afford a car with seat belts for several years. When I was able to afford that “new” car with seat belts, I was always suspicious of the lap belt; I thought it would just slice you in half while your face bounced off the steering wheel or dashboard.

Now with all the air bags and self-tensioning seat belts and safety devices designed to keep you in the car in an accident, I have found religion. I never move without the seat belts fully engaged for everyone. It’s just my way of staying alive for the long term—I’m not going to end it by being stupid (I hope).

I was saddened to read about five teenagers in an accident (all under the age of 18), with three being ejected from the car. Happily, the word is all five will survive though seriously injured—amazing. Seat belts keep you and your loved ones in a steel box designed to crumple around you. Getting ejected from your safety box by not wearing a seat belt is just dumb, I’m sorry to have to say. Teach your family by example, wear yours, always.

Give yourself a hand at saving your hands and fingers.

One safety PPE area that has become the greatest thing since screen doors on submarines (no they don’t, really, no mosquitos on subs) is the variety of great gloves available for every type of work. Cut-proof, stab-proof, oil resistant reflective, NY Yankee’s resistant…you name it, someone makes it. My suggestion to all public works folks is get and wear the correct pair of gloves for your work. Even if your town budget says, “Hey, those aren’t cheap!,” wait till they see the medical bills and workers’ comp costs from a serious hand injury that could have been prevented with the right PPE gloves.

Impossible to hold a chilled beverage, eat chips, handle the remote, and perform other important human functions with this.

Stay safe my friends!!

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Traffic Signal Academy: On-Demand Learning – MUTCD Warrants for Traffic Signals Learning Guide

Traffic Signal Academy_MUTCD Warrants for Traffic Signals Learning Guide

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National Center for Pavement Preservation — Free Webinars!

ncppNational Center for Pavement Preservation — Free Webinars!

The National Center for Pavement Preservation (NCPP) announces the 2020 AASHTO TSP·2 Pavement Preservation Webinar Series.  These webinars are offered FREE to all on a first-come, first-served basis.  You are encouraged to participate in all of the TSP·2 webinars, your participation is not limited to a specific partnership or geographic region.  This series offers an excellent opportunity to learn about current topics and issues in each of the four TSP·2 partnerships.  Registration is limited to the first 500 participants and a separate registration must be completed for each webinar.  We ask that you register only for those webinars you intended to participate in so that there is enough space for everyone who would like to join.  All webinars will begin at 2pm ET/1pm CT/ 12pm MT/11am PT.  Specific information for each TSP·2 webinar is as follows:

Rocky Mountain West — Tuesday, September 29th

Topics

  • Use of RAP in Surface Treatments  — Greg Duncan, Applied Pavement Technology
  • ASTM D8260 Mastic Application — Michael Guymon & Tom Cannon, Maxwell Products
  • New Mexico In-House Chip Seal Program — Lisa Vega, New Mexico DOT

Registration link: https://attendee.gotowebinar.com/register/3603048335917839118

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Midwestern — Wednesday, October 21st

Topics

  • Micro Surfacing Issues and How Illinois DOT Fixed Them  — John Senger, Illinois DOT
  • What Went Wrong? A Case Study in Chip Seal Failure — Todd Shields, Indiana DOT
  • Alternate Delivery Methods of Pavement Preservation — Stacy Smith, Missouri DOT

Registration link: https://attendee.gotowebinar.com/register/384871260260534540

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Southeast — Monday, November 9th

Topics

  • Rejuvenators: Types, Intent and Process — Chris Lubbers, Kraton Polymers
  • Scrub Seal Best Practices — Stan Williams, Ergon
  • Panel Discussion on Implementing Preservation — Sarah Tamayo, Arkansas DOT

Registration link: https://attendee.gotowebinar.com/register/9126147030754143756

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Northeast — Tuesday, December 1st

Topics

  • J-Band Treatment to Eliminate/Reduce Centerline Joint Opening — Bobby Betsold, All States Materials Group & Marcy Lucas, PennDOT
  • Good Construction Practices for Thin Lays — Greg Harder, Asphalt Institute
  • What Could/Should You Do for Pavement Evaluation Before Treatment? — David Peshkin, Applied Pavement Technology

Registration link: https://attendee.gotowebinar.com/register/7453818432209174796

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These webinars were developed from existing agenda topics planned for in-person 2020 TSP·2 partnership meetings and are being hosted on the GoToWebinar platform.  Each webinar will be 90 minutes long and will include time at the end of the session for question and answer. You do not need to be involved with TSP2 to participate.

If you have any questions, please reach out to the NCPP by email at ncpp@egr.msu.edu.

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Innovation Station: FHWA’s Focus on Reducing Rural Roadway Departures — FoRRRwD

innovation_station FHWA’s Focus on Reducing Rural Roadway Departures — FoRRRwD

Thirty people will die today, and every day, in a rural roadway departure—accounting for one third of U.S. traffic fatalities. The Focus on Reducing Rural Roadway Departures (FoRRRwD) initiative provides technical assistance and training to States and local agencies across the country to address this deadly problem. FoRRRwD provides unique approaches and methods to deliver safety countermeasures and projects efficiently. FoRRRwD’s focus areas are identified through its four pillars—all public roads, proven countermeasures, systemic approaches, and safety action plans.

FoRRRwD

Many agencies are recognizing the need to address rural roadway departures on all public roads because over 40 percent of these deaths happen on roads off the State highway system. Not only are State DOTs assisting local agencies and encouraging them to use an appropriate share of Federal safety funds, but many are finding innovative methods to accomplish the goal.

In Connecticut, roadway departures are part of the Critical Roadway Locations Emphasis Area in the State’s 2017-2021 Strategic Highway Safety Plan (SHSP). Countermeasures installed around the state include center line and edge line rumble strips and horizontal curve signing.

To learn more about how your agency can use innovative programs and mechanisms to deliver safety projects, watch this webinar from earlier this year. Additionally, you can visit the FoRRRwD website to learn more about the four pillars and watch the FoRRRwD overview video.

In EDC Outtakes—a series of short interview videos—State practitioners and FHWA personnel give insight into the current round of EDC innovations. In the latest edition, Matthew Enders, of the Washington State DOT, discusses several of the proven countermeasures recommended by the Focus on Reducing Rural Roadway Departures (FoRRRwD) team.

 

Excerpted from EDC News Weekly Newsletter, Published by the Federal Highway Administration, Center for Accelerating Innovation

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Safety Matters: Speed Display/Driver Feedback Sign Program

safety_matters_logoSpeed Display/Driver Feedback Sign Program

The T2 Center, working in cooperation with CTDOT, is pleased to announce a new program aimed at reducing fatal and serious-injury speed-related crashes on rural town-owned roadways. The Speed Display/Driver Feedback Sign Program will provide 119 Connecticut municipalities with two speed display signs each, at no cost to the town, over the course of the next two years.

sm_1_9.2020_useAnalysis of CT crash records from 2016–2019 showed that fifty percent (50%) of fatal and serious-injury crashes, where “exceeded speed limit” or “too fast for conditions” was a contributing factor, occurred on a rural town-owned road. By using a systemic approach and installing speed display signs on roads with similar characteristics, we can be proactive in addressing these types of crashes.

This exciting new program includes delivery of the signs to each identified location, training on the benefit and use of the signs, assistance with installation and monitoring of the signs, and data reporting. Regional Speed Management trainings will also be offered, at no cost, to provide local public works and engineering professionals the opportunity to learn from each other about programs that are underway in Connecticut to address speed management issues. Attending a Regional training is not a requirement to receive the signs but it is strongly encouraged as an important aspect of an overall speed management plan.

I will be contacting the identified towns in the near future to begin working with them on this exciting program.

For more information and assistance with local road safety in your community, contact Melissa Evans, Safety Circuit Rider, at melissa.evans@uconn.edu.

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Warren’s Words of Wisdom: Electric Shock Drowning (ESD) — Never Heard of It? Me Neither, Until Now

warren_words_wisdom_LogoElectric Shock Drowning (ESD) — Never Heard of It? Me Neither, Until Now

Several times during the summer, I would read a story of a fatality at a lake or pool or marina where somehow electricity was in the water that caused people to drown. One I recall was when the owner noticed his Golden Retriever was having problems after jumping off the dock into the lake, and the owner jumped in to help the dog. As soon as the owner went in, he began having problems and ultimately drowned, but the dog did survive. There was a short in the power cable to the dock. What was happening that was causing people to drown? Were they being electrocuted?

Here’s what I learned, it’s an event called Electrical Shock Drowning or ESD. When there is electricity in the water, it will cause your muscles to cramp up and you are unable to move your arms or legs, meaning you will be conscious, but will drown because you will not be able to swim or grab anything or even yell for help. What a horrible way to die!

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https://www.electricshockdrowning.org/

The ELECTRIC SHOCK DROWNING PREVENTION ASSOCIATION has several educational videos and information on how to protect yourself and your family if you boat or go around a marina.  I learned things I was completely unaware of until I looked at their web site. Even if you don’t have boat, spend a few minutes learning about ESD—it could save your life and the lives of people you love!

Underground Cables

Just like the overhead Distribution system, when the cables go underground, you still have Primary (4800v to 23Kv) and Secondary voltages (120/240/480V) to deal with, but instead of being 40 feet in the air, the cables are 12-24 inches under your feet. So how do we protect ourselves if we need to dig with mechanical tools or even dig by hand?

www.9.2020.3First, you need to know that Call Before You Dig (CBYD) is your best friend!! (or as I call refer to it, Call Before You Die). So, CBYD comes out and marks all the underground services. What do all the colors mean?

 

There is lots of equipment and many dangers running below the surface at varying depths, with electricity supposedly around 24” deep (unless going under concrete 2” thick or more, then the cables can be 18” below grade). There have been terrible accidents when someone using a jack hammer or cut saw has gone too deep and hit underground power. Slow and careful is the best way.

Underground electric cables are a different construction than the overhead wires. They are designed to be used in places where the ground and people will be closer but not be at risk just by being close, like the cables coming down a pole mounted riser inside the PVC pipe.

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Overhead Primary cable called Tree wire (no insulation)

 

 

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Underground Primary – notice the Red Stripe – Red on the CYBD mark-out (insulation)

 

It is very important that you recognize this type of cable as you dig, which should be by hand digging if you are within 18’ – 24” of the mark-out center. Once you have uncovered this, you should be careful to not damage the cable. If you inadvertently nick the cable, stop work and contact your utility to inspect it. Don’t be handling the cable, but you can work around it safely. OSHA expects that anyone performing excavation and digging be familiar with the underground hazards and recognize what they are and how to work safely. Each electric utility may have different rules and methods on how they want you to work around underground cables, which could be in PVC pipe or direct buried. I suggest you contact your utility and ask for a representative to come by your next safety meeting and talk about how they expect you to work with underground cables.

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Here’s a recent storm story: Down wires that were burning reached the new plastic gas main and melted it, causing a gas fire in addition to the electrical hazard! Notice the hanging wires and burning grass to the right side and the location of the month-old gas main!

This is a perfect example of electrical step potential. Just walking around this area could kill or injure you. Stay at least one pole section away on the side of the street opposite the wires, do not be under the wires!

Remember, if you get caught in a vehicle and it’s contacting wires, stay in the vehicle and call for help!

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Signal Spotlight: Optimizing Yellow Clearance Intervals: A Proven Safety Countermeasure

traffic_signal_spotlights_logoSignal Spotlight: Optimizing Yellow Clearance Intervals: A Proven Safety Countermeasure

ss.8.20.1At a signalized intersection, the yellow clearance or yellow change interval is the length of time the yellow signal indication is displayed following a green signal indication. The yellow signal confirms to motorists that the green has ended and that a red will soon follow.

Since red-light running is a leading cause of severe crashes at signalized intersections, it is imperative that the yellow change interval be appropriately timed. Clearance intervals are a function of operating speed, the width of the intersection area, lengths of vehicles, and driver operational parameters such as reaction, braking, and decision-making time.

When a yellow change interval is too short, drivers may be unable to stop and unintentionally run the red light. If the interval is too long, drivers may treat the yellow as an extension of the green phase and intentionally run the red light.

ss.8.20.2Municipalities can improve signalized intersection safety and reduce red-light running by reviewing and updating their traffic signal timing policies and procedures concerning the yellow change interval on a regular basis. The MUTCD does not require specific yellow or red intervals but provides general guidance that the yellow change interval should be approximately 3 to 6 seconds.

Current CTDOT practice is to use the kinematic equation outlined in the ITE Traffic Engineering Handbook for the yellow change interval, and a modified version of the kinematic model for the red clearance interval. Yellow change intervals of three seconds to five seconds are typically used.

The yellow change interval for each phase is computed using the following formula:
Y = t+V/(2a+2Ag)

Where:
Y = Yellow change interval in seconds
t = reaction time (use 1 second)
V = 85% percentile approach speed in ft/sec or m/sec
a = deceleration rate of a vehicle (use 10 ft/sec2 or 3 m/sec2)
A = Acceleration due to gravity (32.2 ft/sec2 or 9.81 m/sec2)
g = percent grade in decimal form (+ for upgrade, – for downgrade)

ss.8.20.3While providing an appropriate yellow clearance interval improves safety, it should be noted that there is no additional benefit to making the interval longer than it needs to be. Longer clearance intervals increase lost time at the signal and will reduce the intersection’s capacity.

Resources:
Connecticut DOT Traffic Control Signal Design Manual
https://portal.ct.gov/DOT/Traffic-Engineering/Traffic-Control-Signal-Design-Manual

NCHRP Report 731 Guidelines for Timing Yellow and All-Red Clearance Intervals at Signalized Intersections
http://www.trb.org/Publications/Blurbs/168017.aspx

Guidelines for Determining Traffic Signal Change and Clearance Intervals: An ITE Recommended Practice
https://www.ite.org/technical-resources/topics/traffic-engineering/traffic-signal-change-and-clearance-intervals/

Recorded Webinar: Introducing ITE’s Guidelines for Determining Traffic Signal Change and Clearance Intervals
https://www.pathlms.com/ite/courses/16489

Making Intersections Safer: A Toolbox of Engineering Countermeasures to Reduce Red-Light Running
https://safety.fhwa.dot.gov/intersection/conventional/signalized/rlr/rlr_toolbox/

If you have traffic signal systems questions, please contact: Theresa Schwartz, P.E.,
P.T.O.E. – Traffic Signal Circuit Rider (860) 486-4535 or theresa.schwartz@uconn.edu.

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Safety Matters: Sign Visibility and Retroreflectivity

safety_matters_logo Sign Visibility and Retroreflectivity 

Every day, no matter where we go or what we do, we see signs. Whether it’s the STOP sign at the end of a street, a pedestrian warning sign or the sign directing you to the beach, all of the signs we see are regulated by the Federal Highway Administration’s Manual on Uniform Traffic Control Devices (MUTCD). The size, shape, color and messaging are all specified in the MUTCD and allow for a person to travel from a small rural community in Connecticut to a city like Los Angeles, CA and recognize each and every sign. This is most important when it concerns traffic control signs – it would be nearly impossible to move around safely if regulatory signs weren’t uniform!

Almost as important as their uniformity is their visibility. A sign can only provide information to the roadway users if those users can see it. The MUTCD has the following language with regard to sign design and retroreflectivity.

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Some visibility issues are easy to identify and resolve. A low-hanging branch that blocks a sign can be identified and cut rather quickly. A sign that has been vandalized can be repaired or replaced. More difficult, though, is determining if a sign is no longer retroreflective. During the day, a sign may look worn, but does that make it no longer retroreflective at night? Since Public Works crews work during the daytime, it can be hard to conduct proper nighttime visual inspections of signs. Ensuring that the proper signs are installed and maintained has a measurable impact on roadway safety. Signs that are visible in the day provide information to drivers but may be one of many visual cues to aid the driver in their decision making. At night, when many of those other cues may not be visible, signs become even more important.

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  • Daytime
  • Many cues available 
  • Driver task relatively easy

 

 

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  • Nighttime 
  • Few cues remain
  • Task more difficult

 

 

A sign inventory is an effective way to keep track of the life of signs, which aids in assessing their retroreflectivity. Using an established method to assess and/or manage regulatory and warning signs for retroreflectivity is also an FHWA requirement. The different ways that sign retroreflectivity can be determined are listed below:

  • nighttime visual inspections using comparison panels
  • nighttime visual inspections using calibration method
  • nighttime visual inspections using consistent parameter method
  • measured using retroreflectometer

Many local agencies do not have the ability to bring staff in at night to conduct visual inspections. Another option is to anticipate the expected life of a sign and replace signs on a rotating basis, but this can be costly if signs are needlessly removed. A retroreflectometer can be used during the day and provides an objective measurement; however, they are cost prohibitive for most local agencies. The T2 Center does have two retroreflectometers, as part of the Equipment Loan Program, which can be borrowed by a municipality to conduct sign inspections. More information can be found on our website by clicking here.

Maintaining sign visibility is an important and necessary part of keeping our roadways safe for all users. The better the information is that we provide, the easier it is for the driver to complete the task needed to navigate the road.

Additional information on retroreflectivity requirements can be found in the MUTCD and on FHWA’s website at: https://safety.fhwa.dot.gov/roadway_dept/night_visib/policy_guide/sign_15mins/

For more information and assistance with local road safety in your community, contact Melissa Evans, Safety Circuit Rider, at melissa.evans@uconn.edu.

 

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