Acadiana’s T-Intersection Crash Reduction Initiative

Roadway departure crashes comprise the majority of fatal and serious injury crashes in the Acadiana region. Typical roadway departure treatments focus primarily on lane departure, and include rumble strips, curve delineation, and enhanced striping. However, the treatments for these crash types are highly dependent on roadway geometry, and the Acadiana region needed to address fatal and serious injury crashes that were occurring because of drivers running through the back of T-intersections. These crash types had increased significantly in recent years, and crash reports documented that this rise was largely caused by drivers engaged in phone use.

The Acadiana Regional Transportation Safety Coalition (ARTSC) brought together the Acadiana Planning Commission staff and the Louisiana Department of Transportation and Development’s (DOTD) District 03 traffic engineers to identify intersection locations with a high likelihood of run-through roadway departure crashes. After filtering crashes by roadway departures within a certain distance of an intersection, crash locations were joined with the intersection shapefile in the geographic information system (GIS). The results were analyzed to identify locations with a high number of the target crash types. A separate intersection query was then performed to review the crashes at the identified intersection to document the intersection run-through crashes.

The locations identified as meeting the threshold for run-through intersection crashes were evaluated based on a site visit that documented the existing infrastructure at the location. In total, the team reviewed 124 locations and developed a plan for escalating interventions at 15 intersections. They also identified six intersections to monitor based on prior improvements. Plans ranged from installing T-intersection signage, redundant and oversized stop signs, flashing beacons, and/or transverse rumble strips at the terminal roadway’s approach.

The project utilized minimal funding from the LA DOTD district and local budgets. At the locations where the improvements were implemented, there was at least a 50 percent reduction in run-through intersection crashes, with the majority of locations seeing a complete elimination of this crash type. Overall, run-through crashes fell from 75 to six at intersections on the state system1 , and from 14 to two on the local system locations. The project is ongoing, and additional locations have been selected for improvements in the future. The project can also easily be scaled to a statewide improvement program to address these crash types.

Additional Information

Ashley Moran, Senior Planner with the Acadiana Planning Commission, accepted the Award on November 29th at a ceremony on Capitol Hill.