Effectiveness of Speed Minders in Reducing Driving Speeds on Rural Highways in Pennsylvania; Final rept. for 30 Apr 07-29 Jun 08

摘要

The objective of this project was to determine the effectiveness of dynamic speed display signs (also known as 'speed minders') in reducing vehicle operating speeds. The Pennsylvania Department of Transportation (Penn DOT) has invested in several speed minders. Each engineering district uses the speed minders in an effort to assist in managing vehicle speeds, particularly in locations where the roadway transitions from a high-speed (45 to 55 mph) to low-speed (25 to 35 mph) operating environment. It is common for these regulatory speed limit changes to occur along roadways that pass through rural communities. Penn DOT selected several locations in central Pennsylvania to position the speed-minder signs to evaluate their effectiveness. These locations were primarily along roadways that transition from high-speed to low-speed operations on rural highways; however, several locations were on roadways without regulatory speed changes. Because each engineering district has only a few speed minder devices, it is common that they are placed and activated at a site for a period of 1 week and then rotated to other roadways within the district to provide greater geographic coverage. The objective of this project was to determine the effectiveness of speed minders in reducing vehicle operating speeds. At all evaluation locations, an observational before-during-after study approach was used. The study findings suggest that while deploying speed minders for a period of 1 week has the desired effect of reducing mean speeds while in place, after their removal speeds return to approximately the same level as prior to deployment. There may be a benefit associated with deploying speed minders for long duration at sites in Pennsylvania rather than deploying them for a single week.