Induced Demand: New Empirical Findings and Consequences for Economic Evaluation

New transport infrastructure, such as additional lanes, is often found to coincide with an increase in traffic volume. In the literature the concept of ‘induced demand’ or ‘induced traffic’ is often used. The objective of this study is to provide empirically derived insights in this phenomenon, in the amount of induced demand and in the benefits that adding road infrastructure has for users. To identify the impact that adding infrastructure has on vehicle kilometers and hours of delay, multivariate analyses were conducted on detailed traffic and other data from 2000-2014 to identify the impact that adding lanes has on vehicle kilometers and vehicle hours of delay per month per road stretch. Hereby it is controlled for socio-economic factors, including population, jobs and car use, weather conditions, road works, incidents, and other policy measures. Based on the empirical studies in transportation literature, the authors conclude that if 10% lane kilometers are added, the amount of traffic induced is approximately +2% to +5%. The amount of traffic induced by adding extra lanes at 150 locations ( +10% lane kilometers) to the main trunk network was 4%. When the total network is taken into account, the amount of extra traffic caused by adding lanes is +2%. The share of shifts in departure time choice suggests that evaluations of investments in new road infrastructure could be improved by evaluating the preferred departure time in cost-benefit analyses.

• Supplemental Notes:
  • This paper was sponsored by TRB committee ADB10 Standing Committee on Traveler Behavior and Values. Alternative Title: Induced Demand: New Empirical Findings of the Amount and Composition.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • van der Loop, Han
  • van der Waard, Jan
  • Haaijer, Rinus
  • Willigers, Jasper
• Conference:
  • Transportation Research Board 95th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2016-1-10 to 2016-1-14
• Date: 2016

Language

• English

Media Info

• Media Type: Web
• Features: Figures; References; Tables;
• Pagination: 16p
• Monograph Title: TRB 95th Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Benefit cost analysis; Data analysis; Infrastructure; Traffic delays; Traffic volume; Travel time
• Uncontrolled Terms: Induced traffic
• Subject Areas: Data and Information Technology; Economics; Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 01594835
• Record Type: Publication
• Report/Paper Numbers: 16-1689
• Files: TRIS, TRB, ATRI
• Created Date: Mar 30 2016 9:47AM