Good vibrations: VDOT’s new PTRS safety initiative

Trenton M. Clark, P.E., Executive Vice President, Virginia Asphalt Association

If you ever wondered how dangerous driving has become, look at recent safety statistics:

• 85% of drivers are distracted by their cell phone
• Drivers are on their phone 1 out of every 6 minutes while driving
• 71% of drivers text while driving
• Chances of an accident while talking on the phone is 2.2 times higher
• Chances of an accident while texting is 6.1 times higher
• When dialing a phone number, the chances of an accident is 12.2 times higher1

And while those statistics are frightening, a look at the accident data from Virginia’s 2017 Work Zones is no better. During that calendar year, Virginia’s work zones saw more than 1,330 crashes. Of those cases, nearly half were due to driver speed. The remaining accidents were a result of distracted drivers and alcohol-related. Since distracted driving is normally self-reported, experts believe many of the crashes classified as speeding may have actually occurred due to distracted driving.

Interestingly, the number of accidents due to distracted drivers is more than five times higher than alcohol-related crashes. As stated by Mr. David Rush – VDOT Work Zone Safety Program Manager, distracted driving has become an epidemic across the state.

Currently, PTRS are not required on VDOT contracts unless specifically required in the contract documents. Contractors can elect to use PTRS at their own cost.

PTRS

For years, VDOT has installed rumble strips along rural interstates. In the last five years, VDOT has expanded rumble strips to the centerline of two-lane primary and secondary routes. All of these safety implementations were done to alert the driver that their vehicle was deviating from the travel lane. Starting in 2018, VDOT and several contractors began deploying portable temporary rumble strips or PTRS in work zones where flaggers were present. VDOT forces were directed to use PTRS in an Instructional and Informational Memorandum (IIM) from Traffic Engineering in November 2017.2 After input from the paving and contracting industries, VDOT issued an updated IIM in October 2018.3 The reissued IIM laid out the uses of PTRS and timeline for statewide implementation.

WHAT ARE PTRS?

PTRS are a series of three raised rubber segments. When a vehicle travels over these segments, an audible noise is made that alerts the driver and the flagger. Where PTRS have been used, research has shown a decrease in rear-end collisions and roadway departures.

PTRS are approximately 11 feet long, one foot wide and weigh 100 to 120 pounds each. PTRS must be either orange or black; they must be hinged to aid in moving and installation. For PTRS to function properly, they must be able to withstand an 80,000-pound vehicle and not move more than six inches over eight hours.

WHEN ARE THEY REQUIRED?

Currently, PTRS are not required on VDOT contracts unless specifically required in the contract documents. Contractors can elect to use PTRS at their own cost. However, starting with contracts advertised on and after July 1, 2019, they shall be used when the following criteria are met:

• Two lane roadways
• Work zones set-up during daylight hours
• Duration in the work zone exceeds 3 hours, but less than 72 hours
• The existing roadway speed limit is 35 mph or higher
• Roadway has a marked centerline (i.e., 500 or more vehicles per day)

PTRS should be considered for use on roadways at least 18 feet wide and be located in advance of horizontal curves where sight distance is limited.

Likewise, not all situations apply to PTRS. They should not be installed on loose gravel, surfaces with rutting or bleeding asphalt, or unpaved surfaces. PTRS should not be installed in pedestrian crossings and marked bike lanes.

Also included in the IIM are situations where PTRS may be used. These include roads with speed limits less than 35 mph; one-and two-lane roads where automated flagging devices or portable traffic signals are utilized; certain divided four-lane highways based on VDOT management discretion; and some nighttime operations.

FUTURE OF PTRS

As with all new initiatives, the effectiveness of PTRS will be evaluated by VDOT. Portable Temporary Rumble Strips are widely employed in states such as Texas where they have been used for years. With time, IIM-386 may be revised to cover other applications. For now, read your contracts, understand the traffic control set-up, and keep your employees and the traveling public safe.

ACKNOWLEDGMENTS

Virginia Asphalt Association would like to thank VDOT and Mr. David Rush for his assistance in writing this article. Mr. Rushprovided a presentation at the 2019 Regional Asphalt Seminars on PTRS. The full presentation can be viewed and downloaded at https://www.vaasphalt.org/newsevents/reportspresentations/.

References

1 Rush, D. (2019, March). Portable Temporary Rumble Strips – Reducing Distracted Driving Crashes in Work Zone.
2 VDOT. (2017, November). Instructional and Informational Memorandum – Traffic Engineering 386 (IIM-TE-386).
3 VDOT. (2018, October). Instructional and Informational Memorandum – Traffic Engineering 386 (IIM-TE-386.1).

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