The feasibility of a congestion charge for Cape Town central business district from a traffic engineering perspective

Abstract

There is an ever increasing need to introduce travel demand measures as the ability to construct new and upgrade existing roads to accommodate additional traffic volumes decreases. The City of Cape Town, hereinafter referred to as the City, has forecasted that traffic in the city could continue to increase by two and a half percent per year. To mitigate against the increased traffic volumes, the City is proposing a number of travel demand strategies, including a park and-ride facilities and high occupancy vehicle initiatives in the short term. The City’s draft travel demand management strategy identifies congestion charging as a measure more possible implementation in the medium term. This study investigates the feasibility of introducing a congestion charge from a traffic engineering perspective. This entails determining if there could be a reduction in traffic entering the Central Business District, what type of congestion charge is most suited for Cape Town and what type of technology is most appropriate at this point in time.

In determining the type of charge and technology for introduction in Cape Town, international experience and trials were drawn upon in terms of case studies and research completed. These included developed and developing cities that had either introduced a congestion charge or considered it. To determine the potential level of traffic reduction, transportation elasticities for road pricing/congestion charging were used. This method of calculating the traffic reduction has been used on similar studies and provides a reasonable indication of the potential percentage reduction which could be achieved. The elasticities were based on post-implementation studies undertaken in cities which had introduced a congestion charge or road user pricing. For this study, elasticities between -0.1 and -0.5 were used.

The study found that of the types of congestion charging available, a simple cordon charge, around the central business district (CBD) was most feasible. A cordon area would be more appropriate due to the small charge area involved, the flexibility that it allows and because it does not need to be visually intrusive in terms of roadside and enforcement equipment. The location of the cordon area also allows the key roads around the CBD to become the bypass route for vehicles that currently pass through the area.

In terms of the charge payment system, it was found that presently, a manual payment system would be more appropriate for the city than a tag and beacon system.