Dallas area residents know that in the past several years there have been a number of wrong-way drivers on the Dallas Tollway who have caused fatal collisions. Most of these incidents involve drunk driving.
The tollway authorities have been under pressure to find a solution to this problem, and they have come up with an interesting possibility. Their theory is that drunk drivers keep their eyes lowered when they drive, and will be more likely to see signs posted a couple of feet above the ground rather than at the normal height. Here are excerpts from a press release from the North Texas Tollway Authority explaining the reasoning:
In an effort to reduce the occurrences of vehicles traveling the wrong way on its System, the NTTA received permission from the Federal Highway Administration to experiment with lowered Wrong Way and Do Not Enter signage for two years. The NTTA tested the signs to make sure the new height is crash-worthy and submitted them to FHWA for approval to test on the NTTA System.
The lowered signage was developed as a result of research performed by the NTTA’s Wrong Way Driver Task Force and reports from the Texas Transportation Institute. TTI research indicated lower signs were more likely to be visible to impaired drivers because they tend to focus their eyes down as they look for visual cues along the roadway. In addition, a lower sign is more likely to be within the path of headlights for greater night time visibility. Though deployed in California, the NTTA is the first entity in the country to crash test such signs – a critical step the Authority felt necessary prior to deployment.
The two-year experimental phase began July 13. Standard mounting height is seven feet from the top of the pavement to the bottom of the sign. NTTA test signs will be two feet. The NTTA will test three different signage configurations on a total of 28 ramps throughout the NTTA System. The configurations were chosen based on ramp geometry and potential for visibility. This also allows the flexibility of being able to chose the best configuration for future ramp deployment if the experiment is deemed successful by FHWA and the NTTA.
This is the latest development brought forward by a the Wrong-Way Driver Task Force the NTTA formed in 2009 to combat what is considered a national problem. If the experiment shows the signage is successful in reducing the occurrences of wrong-way drivers, the NTTA can request the Manual on Uniform Traffic Control Devices be changed to allow the lowered sign mounting height as part of the national standards.
Other steps the Authority has used to prevent wrong-way driver incidents: reflective, raised pavement arrows showing the correct flow of traffic on exit ramps; a traffic loop system imbedded in the roadway at all tolling points that will alert the NTTA Command Center when a vehicle is traveling in the wrong direction; and flashing LED signs on the Dallas North Tollway at the south terminus, Cotton Gin/Main and Highway 380 exits.
