The effectiveness of rumble strips installations in speed reduction along major highways in Ghana – The case of N1 highway

Abstract

In response to increasing traffic crashes along highways in Africa, various interventions have been adopted with varied outcomes. Though the specific impacts of various interventions have not been measured, rumble strips appear to be the dominant choice in many countries around Sub-Saharan Africa. Using the Accra-Cape Coast trunk road, a section of the trans-West African highway in Ghana, this study explores the speed reduction effects of rumble strips. In spite of the many traffic-calming interventions introduced on sections of the road, the road is reported to have recorded hundreds of traffic crashes in the last decade. Adopting a quasi-experimental design, thirty-six (36) study sections were delineated, and installed rumble strips were inventoried. Spot speeds were measured on sections “with” and “without” the installed rumble strips, all within communities and known blackspots. Existing data on traffic and road crashes were obtained from secondary sources and reviewed to set the context for effective comparison. The study revealed violations in speed limits at 70% of study locations with only rumble strips installed by 4 km/h. Road traffic crashes tend to cluster with speed ranges of between 54 km/h and 70 km/h. Thus, with the right combinations of interventions, speed and traffic crashes can be substantially reduced along the highway. Policy implications for road safety regulation have also been discussed.

Keywords

• Installation
• Rumble strips
• Speed humps
• Vehicle speed
• Road crashes