Work Zones Need Detailed Research, Planning, and Technology to be Made Safe

After significant pauses in travel due to the COVID-19 pandemic, many Americans are expected to return to their on-the-go lifestyles. At the same time, trends in increased home deliveries and initiatives like the American Jobs Plan could result in more active work zones on the roads, at airports, and on rails than in the recent past.

This article details some of TRB’s valuable resources (including a full list at the end) that can contribute to simultaneously keeping traffic moving and the workforce safe.

“More home delivery means more delivery vehicles (trucks) on our roadways,” says Julius Codjoe, Special Studies Research Administrator at Louisiana Department of Transportation and Development (DOTD) and TRB Volunteer. Codjoe and his colleagues’ survey was presented at a lectern session at TRB’s 100th Annual Meeting.

“You expect people to drive slowly in work zones, but we have seen fatalities in work zones in Louisiana,” he said. “Drivers, unexpectedly coming upon slow or stopped traffic, is usually the cause for crashes in work zones. We know the more unexpected traffic queues you have, the more safety issues that are going to come up. The Highway Capacity Manual (HCM) gives you a way to calculate capacity, and thereby determine where queues will form. Accurately determining this will allow agencies to warn unsuspecting drivers and thereby avoid work zone crashes.”

“What we learned was that ultimately heavy vehicle percentages make the biggest difference in the capacity of the roadway. The formulas we were using were right, but they were off for heavy vehicles. You can have the most complicated model you want, but if your input volumes are wrong, you’re not going to get the right outcomes.”

Put a game plan in place

One of the ways those responsible for safety and disruptions through work zones can help is to develop and implement a transportation management plan. The TRB National Cooperative Highway Research Program’s (NCHRP) Strategies for Work Zone Transportation Management Plans provides guidance on how to select and implement strategies that improve safety and traffic operations in roadway construction work zones.

To evaluate the impacts of these safety plans, NCHRP offers Estimating the Safety Effects of Work Zone Characteristics and Countermeasures: A Guidebook. It provides guidance to encourage the use of a data-driven, comprehensive, collaborative planning approaches for the selection and implementation of effective countermeasures to improve work zone safety.

The policies for ensuring worker safety during quick maintenance projects of 20 minutes or less are explored in NCHRP’s Very Short Duration Work Zone Safety for Maintenance and Other Activities. Case examples from four state departments of transportation (DOTs) highlight approaches that can reduce workers exposure to risk during activities like patching pavements, picking up debris, and placing traffic count tubes.

More work zone planning research, from when to use positive protection through implementation, is forthcoming. NCHRP research will evaluate work zone encroachments and develop guidance to improve safety for workers and the traveling public in roadway work zones.

Using innovative technology to improve conditions

Technology is moving safety forward. Intrusion alert technologies and possible techniques for using artificial intelligence were among the topics discussed at a TRB webinar in July 2020. Presenters discussed technologies that mitigate work zone intrusion, such as an Autonomous Truck Mounted Attenuator, which is also known as an Autonomous Impact Protection Vehicle.

Advances in sensing and equipment control technology can help construction personnel avoid incidents. Integrating these technologies can help too. One option is explored in NCHRP’s Innovations Deserving Exploratory Analysis (IDEA) 2017 report, A Low-Cost Mobile Proximity Warning System in Highway Work Zone. It tests a Bluetooth proximity sensing system, developed with customized software and tested with other commercially available sensing devices, which could potentially detect and alert workers when in a hazardous proximity situation.

Improving the visibility around work zones can be done with more basic tools as well. LED sources of light provide better control and luminaries that can be better aimed than older lighting. NCHRP’s Solid-State Roadway Lighting Design Guide: Volume 1: Guidance develops more comprehensive guidelines in American Association of State Highway Transportation Officials (AASHTO)-standard format for the application of roadway lighting related to the widespread adoption of solid-state lighting.

Results from a study published in TRB’s Transportation Research Record (TRR) suggest that changing the frequency of flashing lights could be effective for indicating to drivers operations that might be unusual. For example, changing a service vehicle’s flashing lights from 1 Hz flashing to 4 Hz flashing when the vehicle travels in reverse could draw the attention of nearby drivers and encourage them to slow down.

“DOTs usually warn drivers of slow or stopped traffic with Dynamic Messaging Signs (DMS). My next goal is to try and get automated warning messages in real time from probe data to portable DMS placed in strategic locations along a work zone,” says Codjoe. He notes that in Louisiana, the DOTD now has access to INRIX probe data and a suite of analytical tools from the Regional Integrated Transportation Information System (RITIS) platform.

A number of active NCHRP and NCHRP IDEA projects are investigating even more devices that could help make Codjoe’s goal possible:

Understanding drivers’ behavior

With a grasp of current practices for work zone speed management, effective policies can be put in place. NCHRP’s Work Zone Speed Management documents the current state of data, procedures, techniques, and technical issues related to observing and comparing work zone speeds.

Different methods can influence driver behavior in safe work zones, depending on the amount and type of enforcement required, the amount of staff time and resources available, and the relationship between highway and enforcement agencies. NCHRP’s 2013 Traffic Enforcement Strategies for Work Zones presents guidance for highway zones with speed limits of 45 mph or greater. The report discusses the planning, design, and operation of strategies, as well as administrative issues to consider. It specifically notes that a memorandum of understanding can be a highly-valuable tool.

The process and timing associated with placing or removing pavement markings may interrupt or impede construction operations and require extensive DOT coordination. What’s more, the entire process can create driver confusion. Additional forthcoming research from NCHRP will explore the process of placement and removal of temporary pavement markings.

Work zone resources aren’t just for roads

Every mode of transportation will require work to be performed at some point. A 300% increase in the number of track worker fatalities and injuries from 2003 to 2008 pointed to an industry-wide issue regarding right-of-way (ROW) employee safety and protection. TRB’s Transit Cooperative Research Program (TCRP) collects knowledge, practice, lessons learned, and gaps in information in its 2012’s Practices for Wayside Rail Transit Worker Protection.

Airport operators looking for construction safety information can turn to TRB’s Airport Cooperative Research Program (ACRP) and the Guidebook for Managing Small Airports, updated in 2019. The guide tracks policies and counsel from the Federal Aviation Administration, state agencies, and trade and industry groups and includes suggestions for managing safety concerns that may result from construction either on the airport property or in the vicinity.

Help to keep workers safe with TRB

Become a friend of any of TRB’s standing technical committees focused on work zone safety, like the Standing Technical Committee on Human Factors of Infrastructure Design and Operations, the Standing Technical Committee on Traffic Control Devices, or the Standing Technical Committee on Maintenance and Operations Management. By becoming a friend, you’ll expand your network, and you can volunteer to help organize conferences, review papers, or participate in other committee activities.

You can also get involved with future Cooperative Research Program work. Look for ongoing information on calls for panel nominations, new projects, requests for proposals, and problem statement research ideas.

Keep up with the latest news and opportunities by subscribing to TRB’s weekly E-Newsletter.

TRB resources cited:

Research published in Transportation Research Record cited:

TRB Standing Technical Committees cited:

TRB events cited: Active CRP projects cited: Additional resources cited:


Beth Ewoldsen, Content Strategist

Transportation Research Board


Published May 10, 2021

This Summary Last Modified On: 5/6/2021

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