DMCA
Traffic Forecasts Ignoring Induced Demand: a Shaky Fundament for Cost-Benefit Analyses Petter Næss 1
| Citations: | 4 - 2 self |
BibTeX
@MISC{Nicolaisen_trafficforecasts,
author = {Morten Skou Nicolaisen and Arvid Strand},
title = {Traffic Forecasts Ignoring Induced Demand: a Shaky Fundament for Cost-Benefit Analyses Petter Næss 1},
year = {}
}
Share
 |
 |
 |
 |
||
OpenURL
Abstract
Although the phenomenon of induced traffic has been theorized for more than 60 years and is now widely accepted among transport researchers, the traffic-generating effects of road capacity expansion are still often neglected in transport modelling. Such omission can lead to serious bias in the assessments of environmental impacts as well as the economic viability of proposed road projects, especially in situations where there is a latent demand for more road capacity. This has been illustrated in the present paper by an assessment of travel time savings, environmental impacts and the economic performance of a proposed road project in Copenhagen with and without short-term induced traffic included in the transport model. The available transport model was not able to include long-term induced traffic resulting from changes in land use and in the level of service of public transport. Even though the model calculations included only a part of the induced traffic, the difference in cost-benefit results compared to the model excluding all induced traffic was substantial. The results show lower travel time savings, more adverse environmental impacts and a considerably lower benefit-cost ratio when induced traffic is partly accounted for than when it is ignored. By exaggerating the economic benefits of road capacity increase and underestimating its negative effects, omission of induced traffic can result in overallocation of public money on road construction and correspondingly less focus on other ways of dealing with congestion and environmental problems in urban areas.
Keyphrases
induced traffic traffic forecast cost-benefit analysis petter shaky fundament induced demand travel time saving road project environmental impact traffic-generating effect road capacity increase latent demand transport model road capacity expansion cost-benefit result transport researcher environmental problem benefit-cost ratio economic performance negative effect model calculation economic benefit present paper available transport model urban area long-term induced traffic short-term induced traffic serious bias road capacity public money economic viability road construction public transport land use adverse environmental impact
