The relative effectiveness of a hidden versus a visible speed camera programme

Area of Science:

• Road safety
• Traffic enforcement technology
• Public policy evaluation

Background:

• Mobile speed cameras have been utilized in New Zealand since 1993, primarily at crash-prone sites.
• Visible speed camera enforcement targets specific 'speed camera areas' with a history of speed-related crashes.

Purpose of the Study:

• To evaluate the initial impact of a trial involving hidden speed cameras compared to visible enforcement.
• To assess changes in vehicle speeds, crash rates, casualty numbers, and public attitudes.

Main Methods:

• A one-year evaluation of a hidden speed camera trial in 100 km/h zones.
• Comparison of data from the trial region with the rest of New Zealand employing visible cameras.
• Analysis of speed, crash, and casualty data, alongside public attitude surveys.

Main Results:

• Hidden cameras, coupled with publicity, correlated with net reductions in speeds, crashes, and casualties across 100 km/h roads.
• The impact of hidden cameras was more generalized across all roads compared to the localized effects of visible cameras.
• Public attitudes showed initial changes but largely returned to pre-trial levels.

Conclusions:

• Hidden speed cameras demonstrate a broader effectiveness in reducing road trauma and speeding than traditional visible enforcement.
• The trial suggests a potential for wider application of hidden speed camera technology for enhanced road safety.
• Longer-term evaluation is necessary to fully understand the sustained effects of hidden speed camera programs.