THE ECONOMICS OF MOTORIST INFORMATION-SYSTEMS REVISITED

The literature on the implications of the implementation of motorist i nformation systems is ambiguous, particularly with respect to the econ omic consequences. This paper aims to shed more light on the potential economic costs and benefits of these new technologies by reviewing an d combining results obtained in the literature. Furthermore. future re search directions, essential for an increased understanding of these s ystems, are pointed out. It is first argued that a motorist informatio n system is not a normal economic good; the benefits accruing to the e quipped road users are dependent on the level of market penetration. A t most levels of market penetration a motorist information system is m ost likely to generate a positive external effect for non-equipped mot orists and a negative external effect for those already equipped. Howe ver, in terms of travel time, the equipped road users will outperform the non-equipped ones. Next, the economic consequences of these peculi arities are identified, particularly with respect to the role of the g overnment. Attention is also paid to the traffic generating properties and the market potential of motorist information systems. It is concl uded that the implementation of a motorist information system will, ow ing to an efficiency improvement on the road network, generate more tr affic. The size of this newly generated traffic is uncertain and depen dent on the kind of information system, the behavioural responses of t he road users, the particular network under consideration and the leve l of market penetration. This paper finally concludes that, particular ly in networks with recurrent congestion, the benefits to equipped dri vers diminish as the level of market penetration increases. These syst ems have a better economic perspective in volatile road networks, i.e. networks with non-recurrent congestion.