Average Speed Enforcement

Automated enforcement of speed violations has been widely credited with contributing to fatality reductions overseas. This technique is not in common use today in the United States. It has proven to be controversial and politically unpopular in some jurisdictions that have applied it, although progress has been made in gaining acceptance of the technique. Despite these issues, the experience of the international community with this enforcement technique has demonstrated that sustained and intensive enforcement, rationally organized and managed, can alter driver behavior sufficiently to product worthwhile systemwide safety improvement.

Successful speed management initiatives in other countries are of high visibility, are long term, target major portions of the road network, sometimes use intensive enforcement methods, and monitor progress toward publicly declared speed and crash reduction objectives. No U.S. speed management program in operation today is comparable in scale, visibility, and high level political commitment to the most ambitious speed management programs in other countries. The evidence from numerous research studies, synthesized in several credible reviews, is that reducing the mean speed on a road reduces injuries and fatalities in crashes on the road. Speed reductions reduce casualty risk. Automatic enforcement is a very efficient method of accomplishing speed reductions. And at the same time the enforcement equipment can be used to identify vehicles of interest including stolen vehicles and amber alert vehicles.

The most basic system involves two cameras capturing license plates with a specific known distance between the two capture points. Time stamped data from the first camera is sent the second camera via the internet. If an internet connection is not available at either camera site, the camera can be configured with a 4G interface. The second camera searches the traffic for a matching license plate. Having found a match, the camera calculates the average speed of the vehicle using the distance between the capture points divided by the transit time. If this speed exceeds the preset limit for this roadway, the information is passed to the enforcement agency. The enforcement agency can then issue a citation to the owner of the vehicle. The second camera system includes a web site. A police car downstream from the second camera can log into this website and view violations on a real time basis for immediate enforcement.

In a larger implementation, a single central server can accommodate a large number of cameras. The TDS Average Speed Enforcement System design is shown below. The system uses a 2 megapixel monochrome version of the TDS Sighting Pro camera system along with a powerful IR illuminator for good 24 hour performance without the distraction of a visible flash. The system is very easy to install. It can be deployed on any roadways where there are no stopping points under normal conditions.