Deterrent Effect of Fixed-Site Speed Enforcement on Freeways

Speeding is quite common on freeways, and speed cameras often have limited coverage. Thus, the effect of them on speeding behavior is unclear. This lack of knowledge on the effect of the cameras may lead to irrational decision making in terms of investment in and configuration of enforcement facilities. In this study, sample speed data were collected at five locations near a speed camera on the G45 Freeway (i.e., the Daguang Freeway) in China. Statistics showed that the distance effect model of the speed camera can be represented by a concave parabolic function. Speeding drivers begin to slow down to speed limits when they approach advance warning signs, and then they immediately speed up after passing the enforcement site. The deterrent effect of fixed-site speed enforcement is limited to a 300-meter range. Deterrence theory was used to conclude that there is an obvious distance halo effect for fixed-site speed enforcement locations. The findings of this study imply that the deterrent effect of fixed-site speed enforcement is weak due to its short effective distance and overt form of control. Ultimately, reasonable configuration of enforcement facilities and use of fixed-site facilities in combination with mobile speed enforcement are appropriate methods that can be used to reduce speeding.