ATSSA launches case studies on work zone safety solutions
Series includes six parts to be released at 2021 Convention
ATSSA has collaborated with roadway safety infrastructure industry professionals to produce six new case studies this year. In this issue of The Signal, we look at the first two studies:
• Innovative Work Zone Pavement Markings and Traffic Control Applications
• Innovative Technology Applications in Work Zones
The next two case studies will be featured in the Sept./Oct. issue of The Signal. The final two are planned for the Nov./Dec. issue.
The six case studies will be combined into one case study booklet and officially released at ATSSA’s 51st Annual Convention & Traffic Expo scheduled for Jan. 29–Feb. 2 in San Diego. Case study booklets are a member benefit and available for digital download at ATSSA.com/Case-Studies. Hard copies are also available for purchase on the ATSSA website. Booklets are available to non-members for a nominal fee and to members at discounted prices.
Case Study 1 Innovative Work Zone Pavement Markings and Traffic Control Applications
This lane weave, known as the “Arkansas Shift,” is used in several U.S. states
Promoting safe driving behavior in work zones is an ongoing challenge for many departments of transportation (DOTs). Finding ways to help drivers clearly see temporary traffic pattern markings and know what to expect by making work zone traffic patterns consistent can help reduce crashes and injuries, as research in three states has found.
The Wisconsin Department of Transportation (WisDOT) sought a way to ensure drivers could clearly see temporary changes in lane alignment.
After researching the use of orange paint in work zones in Canada, WisDOT obtained Federal Highway Administration (FHWA) approval to conduct an 18-month experiment using orange paint within the work zone.
Public perception was so positive that FHWA eventually extended the experimental period for two years. Costs were higher for orange paint, but WisDOT concluded there was enough increase in overall safety to justify use.
Video evidence showed drivers maintained their lanes better, and WisDOT received 95 percent fewer complaints regarding markings during the test period.
Additional test runs for the orange temporary pavement markings are in the works in California, Kentucky, and Texas. The orange markings could have future benefits for connected and automated vehicles, which could easily recognize a lane shift by picking up the distinct color.
Michigan’s Department of Transportation (MDOT) took another approach to improving visibility of temporary lane markings, developing “Lead and Lag Tails” at the start and end of traffic pattern changes. These are solid white, 6-inch-wide lane markings placed prior to a lane shift and where normal traffic patterns resume. MDOT also introduced a more durable temporary tape for markings, which takes one-fourth of the time to remove, reducing the amount of time workers spend on the roadway.
The Arkansas Department of Transportation (ArDOT) uses a standardized merging traffic control pattern on all projects across the state that require freeway lane closures. It is known as “the Arkansas Shift” and resulted from the observation that maintaining consistent driver expectations increases safety and reduces crashes at merge points in-state work zones. In this lane weave pattern, drivers always merge from right to left. Even when the left lane is closed, traffic is first brought to the left, then directed back to the right farther downstream.
Case Study 2 Innovative Technology Applications in Work Zones
Technological innovations continue to improve work zone safety. The “smart work zone” offers potential safety benefits to motorists, flaggers, and workers, as an increasing array of devices can provide real-time information to promote safer driver behavior.
The Iowa Department of Transportation’s Smart Work Zone Expansion Group developed a requirement for the use of smart arrow boards on all interstate projects beginning with the October 2020 contract letting season.
Smart arrow boards are equipped with a cellular modem and GPS antenna. They capture data on the starting point of work zone lane closures. Navigation apps can use this information to warn drivers of upcoming lane closures in real-time.
Other innovative technologies explored include:
Navigation apps use information from smart arrow boards to warn drivers of upcoming lane closures
• Automated Flagger Assistance Devices (AFAD), which allow properly trained flaggers to control traffic from a safe location off the shoulder of the roadway.
• Worksite Access Systems, which use sensors to trigger flashing lights that alert motorists of trucks entering the traffic space from the workspace, reducing close calls and improving awareness of the speed variance between motorists and trucks entering traffic.
• Smart Work Zone Sensors, which can provide real-time data on the location of work zones, the location of devices, maintenance needs, and other information.
Watch for details on the next two case studies in the Sept./Oct. issue of The Signal.
Navigation apps use information from smart arrow boards to warn drivers of upcoming lane closures.
To ease the integration of these smart arrow boards, all of Iowa’s smart work zone device information is routed through central traffic management software. Iowa DOT requires all rented work zone devices to be configured to communicate with their existing software.
To improve traffic management at driveway entry locations on two-way roads, the Michigan Department of Transportation (MDOT) deployed the Driveway Assistance Device (DAD).
The DAD is a portable, trailer-mounted traffic signal head that can be placed at driveway entrances to one-lane work zones. It is meant to supplement other traffic control devices and flaggers within the work zone and can help motorists safely enter the work zone through the display of traffic signals. Since it started piloting the DAD in 2015, MDOT has gotten the per-unit price down to $1,950. MDOT determined that the DAD is most appropriate for low-volume driveways.
This article was featured in the July-August issue of The Signal. The Signal is an ATSSA publication. To learn more about ATSSA including becoming a member, visit https://www.atssa.com/