Efficacy of Interventions and Incentives to Achieve Speed Compliance in the Informal Public Transport Sector

The informal public transport industry in South Africa, primarily dominated by minibus taxis is noted for poor compliance and disregard towards posted speed limits. They go as far as driving over the differentiated speed limit of the lighter passenger vehicles used for private transport. This paper compares and evaluates improvements in their speed compliance using two renowned interventions: automated Average Speed Enforcement (ASE), and auditory Intelligent Speed Adaptation (ISA). It also investigates the impact of each intervention on fuel consumption to provide an additional incentive to the most efficient intervention. The main finding was that for minibus taxis, ASE needs ISA as a supplementary intervention. It was discovered that the drivers showed little or no behavioural change while driving on the ASE route, while the introduction of the ISA system resulted in significant changes bringing violation frequencies down to 47.4% from 81.2% on the enforcement route. These behavioural changes also resulted in lower fuel consumption rates especially while the ISA system was active. However fuel economy did not seem to work as a self-regulatory incentive for speed compliance.