Crash effects of speed cameras that were installed in the years 2000 to 2010 were evaluated in a before-after study. On road sections of medium length (100 m upstream to 1 km downstream of the speed cameras) a statistically significant reduction of the number of injury crashes by 22% and a non-significant reduction of the number of killed or severely injured (KSI) by 24% was found. On short (100 m upstream to 100 m downstream of the speed cameras) and long (100 m upstream to 3 km downstream of the speed cameras) road sections no statistically significant effects were found.
For speed cameras that were installed in 2004 or later more favorable effects were found. The number of injury crashes was reduced by 9% on long and by 32% on medium road sections, and the number of KSI was reduced by 39% on long and by 49% on medium road sections. The results for KSI on the short sections are highly uncertain. The length of the before and after periods is three years before and after installation for each speed camera.
The more favorable effects of speed cameras that were installed in more recent years are probably due to changed criteria for the installation of speed cameras and increased compliance with the criteria. The decreasing effect with increasing distance from the speed cameras is probably due to the decreasing effect on speed.
