The effects of conspicuous traffic enforcement on speeding behaviors: a study of speed reduction response.

• Author: Dowling, Kevin W.

Purpose

In law enforcement, it is the purpose of speed enforcement, commonly referred to as "traffic radar enforcement," not only to detect motorists engaged in speeding and issue citations, or tickets, when appropriate, but to use this punitive method to alter the perceived risk associated with speeding behavior. Ideally, both enforcement and presence combine to increase the level of motorist obedience to speed limit laws. Traditionally, this is achieved by law enforcement professionals who use either a marked or unmarked law enforcement vehicle and employ a measuring device to record the speed of motorists passing through designated speed enforcement zones. Citations, or tickets, are then issued to motorists who jeopardize public safety by exceeding posted speed limits. One of the results of speed enforcement is the compliance of the motorist with posted speed limits as he/she passes through a speed enforcement zone and even after he/she does so.

This study seeks to determine the best method of using law enforcement presence to reduce or eliminate the speeding behavior of motorists. It is not designed to ascertain the best way to catch speeding motorists; rather, it seeks to learn the most effective method for positioning and displaying law enforcement vehicles to reduce future speeding infractions. In so doing, this study analyzes the speeding behavior of motorists when faced with the presence of either marked or unmarked law enforcement units, located at varying distances from the motorist, employing differing methods of concealment. Through an analysis of the motorists' speed adjustment when confronted with these various methods of speed enforcement, this study tries to identify the best method of using law enforcement vehicles in order to have the greatest impact on the 'Speed Reduction Response' behavior of motorists.

Rationale

Speeding, quite clearly, is one of the major factors that contribute to traffic accidents and accident-related fatalities in the United States. According to the National Highway Traffic Safety Administration (NHTSA), the economic cost to U.S. citizens resulting from speeding-related crashes in 1999 was estimated at $28 billion. (1) That study also found that speeding accounted for approximately thirty percent of all fatal crashes in 2000, resulting in 12,628 deaths. (2) That trend has increased in recent years. In 2005, the United States Department of Transportation (USDOT) reported that speeding had become "a factor in nearly one-third of all fatal crashes." (3) The USDOT also estimated that speed-related car accidents cost U.S. citizens $44,193 per minute. (4)

The risk of injury and fatality to the motoring public increases as the speed limit increases. As the severity of a crash and its effect on the occupant(s) of a motor vehicle increase with speed, the effectiveness of occupant restraints and vehicle safety features decrease. Thus, the probability of death, disfigurement, or debilitating injury increases with higher rates of impact. Such consequences double for every ten miles per hour over fifty miles per hour that a vehicle travels. (5) An NHTSA report confirms this finding, stating that "more than half of fatal crashes occurred on roads with posted speed limits of 55 mph or more." (6) This is evident in North Carolina where, in 2005, "speeding was the leading violation in fatal crashes." (7) In fact, in North Carolina "one person is killed or injured in speed related crashes every 10.3 minutes," including the thirty-eight victims of fatal crashes in Buncombe County, the focus of this study? Given these statistics, it is easy to see that the ability for law enforcement to have a significant impact on the speeding behavior of motorists is of critical importance.

Method

This study seeks to measure the 'Speed Reduction Response' (SRR) of motorists as they pass through a designated speed enforcement zone. Subject vehicles were paced as they passed through one of five such areas. During "pacing," a trained law enforcement officer matches the speed of a "target...