Institute for Transportation

As part of efforts to better understand the unique challenges posed by work zones, a project funded by the Smart Work Zone Deployment Initiative (SWZDI) through the Federal Highway Administration was completed in late 2023 that looked specifically at anti-tailgating messaging strategies.

Researchers from the Institute for Transportation’s (InTrans’) Center for Transportation Research and Education found that by maintaining sufficient car-following distances, drivers are better able to react to the unexpected, unfamiliar, and complex situations and environments commonly seen in work zones.

“Unsurprisingly, rear-end collisions are the most common type of crash in work zones,” said Jing Dong-O’Brien, a transportation researcher and principal investigator of the SWZDI project.

She added, “Because of the inherent dangers of tailgating, safety in work zones requires proactive intervention. Anti-tailgating messaging strategies can help mitigate tailgating tendencies, as well as the risk of rear-end collisions.”

The research was conducted over two phases. In the first phase, anti-tailgating signs and messages for both fixed signs and dynamic message signs (DMS) were devised by a panel of traffic safety professionals, traffic engineers, and academic researchers and then evaluated for clarity and emotional response through a survey of potential users. Additional surveys were conducted in later stages to further determine user reaction.

Ultimately, one fixed sign and a rotation of five daily anti-tailgating DMS messages were selected for phase two field testing at two construction sites.

The research found that positive messages like PREVENT CRASHES and KEEP YOUR DISTANCE evoked overall positive impressions and demonstrated high intelligibility. In comparison, negative-toned messages like NO TAILGATING and even messages like STAY 200 FEET APART, which included specific numerical values for recommended following distances, were often perceived as confusing.

During the field tests, the researchers observed that the use of overhead DMS, fixed signs, or a combination of both often lead to a significant increase in average headway within the work zone compared to upstream locations.

“We also saw a marked decrease in severe tailgating events with the installation of fixed signs,” said Dong-O’Brien.

The results of this study provides a foundation for improved work zone safety strategies that can greatly improve safety in work zones and reduce tailgating. However, more research is needed to further refine how to best target tailgaters specifically, which includes looking at the effectiveness of graphical fixed signs in the field and the placement and configuration of DMS.