Evaluation of Best Practices in Traffic Operations and Safety: Phase I: Flashing LED Stop Sign and Optical Speed Bars

In a previous extensive review of overseas literature, researchers identified 42 traffic operations and safety technologies and practices that were not currently deployed in Virginia. These were evaluated for their potential application in Virginia, and 12 measures were determined to be good candidates for piloting. Two of the measures, a flashing light emitting diode (LED) stop sign and optical speed bars (two patterns) were installed at three locations in Virginia for before and after evaluations. The flashing LED stop sign was installed at a T-intersection in western Albemarle County, Virginia, where the number of crashes was higher than expected. The measures of effectiveness for the sign were average speed of drivers approaching the sign and compliance with the sign. Average speeds decreased significantly (statistically) after the sign was installed, but only by 1 to 3 mph. Speeds decreased more during the night than during the day. The results of the compliance study were inconclusive Optical speed bars were installed on the centerline and edge line on both approaches to a short section of two-lane roadway in Fairfax County, Virginia. The section of roadway is hazardous, as it has inadequate vertical and horizontal alignment, narrow lanes, and reduced shoulders. A number of crashes had occurred on the section over the years, including a recent fatality. Average speeds both decreased and increased after installation, and the decreases were statistically significant right before and in the middle of the section. The decreases ranged from 1 to 3 mph. Optical speed bars were also installed across lanes on a major, four-lane undivided highway, at two approaches to a reduced speed limit zone in the town of Zuni, Virginia. Average speeds both decreased and increased after installation. The decreases were statistically significant at the beginning of the 45 mph speed zone on each end of town. The decreases ranged from 3 to 10 mph. Given the general positive results of the installations, the report recommends that flashing LED stop signs and optical speed bars be considered as safety countermeasures at appropriate locations where the numbers of crashes or crash rates are higher than expected or where excessive speeding occurs. A costs and benefits assessment indicated that, generally, the benefits in terms of reduced crashes exceeded the costs of the installed measures if only one crash was prevented.

• Record URL:
  http://www.virginiadot.org/vtrc/main/online_reports/pdf/07-r34.pdf
• 
• Record URL:
  https://rosap.ntl.bts.gov/view/dot/19846
• Corporate Authors:

  Virginia Transportation Research Council

  530 Edgemont Road
  Charlottesville, VA  United States  22903

  Virginia Department of Transportation

  1401 East Broad Street
  Richmond, VA  United States  23219

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Arnold Jr, E D
  • Lantz Jr, K E
• Publication Date: 2007-6

Language

• English

Media Info

• Media Type: Print
• Edition: Final Report
• Features: Appendices; Photos; References; Tables;
• Pagination: 41p

Subject/Index Terms

• TRT Terms: Benefit cost analysis; Best practices; Crashes; Fatalities; Flashing; Highway operations; Highway safety; Light emitting diodes; Road markings; Speed; Speed limits; Stop signs; Two lane highways
• Uncontrolled Terms: Optical speed bars
• Geographic Terms: Virginia
• Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors; I73: Traffic Control; I82: Accidents and Transport Infrastructure;

Filing Info

• Accession Number: 01055743
• Record Type: Publication
• Report/Paper Numbers: FHWA/VTRC 07-R34, VTRC 07-R34
• Contract Numbers: 78971
• Files: NTL, TRIS, ATRI, USDOT, STATEDOT
• Created Date: Aug 27 2007 4:43PM