Abstract
The author considers the advantages of congestion charging and compares a number of systems in operation. Mechanisms compared include a) 24 hour manual toll collection, b) 24 hour electronic toll collection, c) cordon pricing with manual toll booths and a reserved lane, d) supplementary licensing, e) electronic road pricing with automatic vehicle identification (alone) and f) electronic road pricing with smart card-type AVI technology. Aspects considered include simplicity, transparency, anonymity, payment options, efficiency, flexibility, reliability, security, cost benefit analysis, modularity and compatibility with other systems.