VTRC researchers test flashing stop sign to alert drivers
Pilot project studies safety practices used elsewhere for Virginia
An LED Stop Sign
CHARLOTTESVILLE – Failing to obey a stop sign is more than illegal,
it can be downright dangerous.
So to learn if more visible stop signs can make the difference between coming to a complete stop and “blowing through,” the Virginia Department of Transportation (VDOT) and its research arm, the Virginia Transportation Research Council (VTRC), will be testing a very conspicuous stop sign to find out if it can help drivers make that full stop at an intersection.
VDOT will install a “flashing stop sign” on Route 151 at its northern terminus at U.S. 250 near the Albemarle-Nelson county line on Wednesday, June 14. This is part of a larger project the Research Council is conducting to determine whether certain safety measures used successfully in other states and other countries will work as well in Virginia.
The flashing stop sign will be identical to standard 48-inch by 48-inch oversized signs except that it will have very bright red flashing LEDs (light-emitting diodes) at each corner. The hope is that these bright flashing lights will send a stronger message to drivers northbound on Route 151 obey the upcoming stop sign.
The researchers are using traffic counters on the road and conducting visual surveys to determine, before and after the sign’s installation, whether this more conspicuous stop sign significantly affects driver compliance at the intersection. A similar study conducted in 2003 by the Texas Transportation Institute (http://tti.tamu.edu/documents/4271-1.pdf) found that flashing stop signs tested at two sites reduced the number of vehicles “not fully stopping” by nearly 29 percent. That study also reported a 53 percent reduction in “blow-throughs” (not stopping at all).
In selecting this intersection for the pilot project, VDOT traffic engineers noted that drivers continually fail to comply with the regular stop sign. Additionally, drivers approach the intersection with U.S. 250 at a high speed – Route 151 has a 55 mph speed limit – the northbound lane is on a vertical and horizontal curve with limited sight distance, and motorists approaching the intersection may be complacent because of the lack of other stops signs along the road.
To inform drivers of the impending stop, VDOT also has installed two sets of “Stop Ahead” signs along the road and two sets of rumble strips to slow the drivers.
“While the Federal Highway Administration has approved using flashing stop signs throughout the nation, they have never been installed in Virginia,” said Ken Lantz, one of the VTRC scientists conducting the project. “In addition to testing the sign’s effectiveness on driver behavior, this pilot project will also help VDOT and the Research Council decide if this type of stop sign should be used more frequently in Virginia.”
As part of this same safety project, the Research Council is also studying whether “optical speed bars” – a series of lines painted at decreasing intervals on the road – will visually give drivers the perception they are moving faster than intended. This line pattern is also meant to get drivers’ attention so they will slow down. VDOT installed a test site with these bars in Fairfax County in May; another site is slated for installation later this year in Isle of Wight County. (See http://vtrc.virginiadot.org/BriefDetails.aspx?Id=20 for more information about this part of the project.)
The overall cost of the overall yearlong project is approximately $100,000. The manufacturer of the flashing stop sign is providing the equipment for this part of the study at no cost to VDOT.
The Virginia Transportation Research Council is a partnership of VDOT and the University of Virginia and is located on the U. Va. grounds in Charlottesville. More information about VTRC is available at http://vtrc.virginiadot.org .