Evidential-Based Guidelines for Temporary Speed Limits

Road works zones are associated with an increase in accidents compared to the pre-work period [1, 2], with excessive speed being a major causal factor [3, 4]. This study examined the setting of Temporary Speed Limits (TSLs) for road work sites conforming to the Transit New Zealand Code of Practice for Temporary Traffic Management (CoPTTM) [5].
The two main aims of the study were to determine whether driver speeds were reduced to the level of the TSL and whether driver perceptions were related to their observed speeds. A secondary aim was to examine whether the level of visibility at a site affected driver speeds. Observed vehicle speeds were used to judge the effectiveness of the current guidelines.