SACRAMENTO — Reports on a three-year pilot program, released July 13 by Caltrans and the University of California-Davis Advanced Highway Maintenance and Construction Technology (AHMCT) Research Center, highlight ways to prevent often-deadly collisions involving wrong-way drivers.
One of the prevention measures included in the pilot program — reflectors that alert drivers they are entering the roadway in the wrong direction — was so successful at deterring wrong-way drivers that Caltrans has already installed the reflective markers on hundreds of miles of highways. In San Diego, the number of wrong-way drivers decreased by 44% after the reflectors were installed.
“Adding the two-way reflective markers proved to be so effective that Caltrans updated its statewide design standards,” said Toks Omishakin, director of Caltrans. “It’s a low-cost measure we can use throughout the state to deter wrong-way drivers and potentially save lives on California’s highway system.”
During the pilot program, Caltrans installed and tested different ways to deter wrong way drivers along exit ramps in Sacramento and San Diego, including:
- Two-way reflective pavement markers that show white or yellow to right way drivers, and red to wrong way drivers;
- “Wrong Way” signs at the off-ramps;
- “Do Not Enter” signs equipped with LED lights flashing 24 hours a day; and
- Active monitoring systems that use radar to detect wrong-way drivers. These systems activate a secondary set of LED signs when a wrong-way driver enters the ramp and sends real-time alerts and photos to Caltrans and the California Highway Patrol (CHP).
Caltrans monitored the exit ramps throughout the pilot period and discovered that the two-way reflective pavement markers were an effective measure against wrong-way drivers. The department is installing them as it performs maintenance or repaving.
Signs with flashing LED signs also showed promise at preventing wrong-way collisions, and Caltrans will continue to monitor the signs’ impact to determine whether to expand their use at exit ramps across the state.
The pilot program was developed following 10 wrong-way driver-related collisions on Sacramento and San Diego area freeways during the first six months of 2015. During the three-year program, UC Davis AHMCT researchers partnered with Caltrans to conduct a second study using a vision-based site monitoring (VBSM) system in Sacramento to better understand the actions that lead to wrong-way driving incidents.
“Our hypothesis was that some of the causes of wrong-way driving start before a driver enters the ramp,” said researcher and AHMCT co-director Ty Lasky, who helped lead the study. “In order to test this, we wanted to extend our field of view to capture as much of the roadway around the exit ramp as possible.”
The VBSM system consisted of a camera, analytical software, solar panels and a modem mounted on poles near exit ramps. The system recorded video whenever the camera detected a wrong-way driver, which allowed the team to study the vehicle’s path before, during and after a wrong-way driving incident.
“The video gave us a more comprehensive understanding of driver behavior and factors that contribute to wrong-way driving,” said Bahram Ravani, UC Davis distinguished professor and AHMCT. “This opens the door for further deployment of our system across the state as counties and municipalities try to mitigate wrong-way driving.”
While wrong-way crashes are fairly rare, the consequences of such accidents are generally severe.
“Wrong-way crashes do not happen very often but when they do occur, they are typically head-on crashes, resulting in death or severe injuries,” said CHP Commissioner Warren Stanley. “Information obtained through this pilot program is being used to help prevent these crashes and save lives on California roadways.”
On average, 37 people are killed in wrong-way collisions each year on California’s highways. Most wrong-way incidents are caused by drivers who are severely impaired, and the incidents occur in the left-hand lane for vehicles that are traveling in the correct direction.
“Seeing someone driving the wrong direction is a scary sight and a clear danger to other road users,” said Barbara Rooney, director of the Office of Traffic Safety (OTS). “Maintaining safe driving behaviors is critical in preventing crashes that have tragic consequences.”
To read the Caltrans and UC Davis AHMCT studies, click here.