Aerodynamic Benefits from Close-Following

  • F. Browand
  • M. Zabat
  • P. Tokumaru


Many believe that the highway congestion experienced in virtually all major urban areas in the United States is the most serious impediment to continued economic growth. Space limitations and cost will probably preclude the construction of significant quantities of new highway in the immediate future. As estimated from several recent freeway projects in Los Angeles, highway construction cost in Los Angeles County is approaching $12 million/lane per mile. To make a modest increase of 25% in the number of highway lane-miles in the Los Angeles County urban area would represent an investment of the order of $12 billion. (The costs are presumed to be similar for other urban areas in the United States.) It is not realistic to suppose that funding support of this magnitude would be available, or necessarily advisable. Rather, it is the more efficient use of the presently available highway system that is the focus of the automated highway (AHS) concept. To improve the operation of the highway system, two solutions might be considered: either decrease the average vehicle width to produce more lanes of traffic, or increase the traffic flow of existing lanes. Automobiles and trucks can be made narrower but not significantly so, and only at great cost. The second choice is more compelling because large improvements in the flow (or throughput) along a highway are possible by incorporating the orderly movement of vehicles, together with a reduction in the longitudinal spacing between vehicles. Both items are contained in the close-following concept.


Wind Tunnel Drag Coefficient Drag Reduction Lead Vehicle Wind Tunnel Measurement 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    K. Petty, Freeway service patrol (FSP) 1. 1: The analysis software for the FSP project, PATH Research Paper No. UCB-ITS-PRR-95-20 (1995).Google Scholar
  2. 2.
    M. Zabat, S. Frascaroli, And E Browand, Drag measurements on 2, 3 & 4-car platoons, SAE Paper No. 940421 (1994).Google Scholar
  3. 3.
    M. Zabat, N. Stabile, S. Frascaroli, And F. Browand, Drag forces experienced by 2, 3 & 4-vehicle platoons at close spacings, SAE Paper No. 950632 (1995).Google Scholar
  4. 4.
    M. Zabat, N. Stabile, And F. Browand, Estimates of fuel savings from platooning, Proc. 5th Annual ITS America Meeting, Washington, DC, 1995.Google Scholar
  5. 5.
    M. Zabat, N. Stabile, S. Frascaroli, And F. Browand, The aerodynamic performance of platoons, PATH Research Paper No. UCB-ITS-PRR-95-35 (1995).Google Scholar
  6. 6.
    J. L. Hess And A. M. O. Smith, Calculation of potential flow about arbitrary bodies, Prog. Aeronaut. Sci. 8, 1 - 138 (1966).CrossRefGoogle Scholar
  7. 7.
    W.-H. Hucho And G. Sovran, Aerodynamics of road vehicles, Annu. Rev. Fluid Mech. 25, 485 - 537 (1993).CrossRefGoogle Scholar
  8. 8.
    A. Rosxxo And K. Koenig, Interaction effects on the drag of bluff bodies in tandem, in Aerodynamic Drag Mechanisms of Bluff Bodies and Road Vehicles, edited by G. Sovran, T. Morel, and W. T. Mason ( Plenum Press, New York, 1978 ), pp. 253 - 286.Google Scholar
  9. 9.
    M. Gharib And A. Rosxxo, The effect of flow oscillations on cavity drag, J. Fluid Mech. 177, 501 - 530 (1987).CrossRefGoogle Scholar
  10. 10.
    G. Sovran, Tractive-energy-based formulae for the impact of aerodynamics on fuel economy over the EPA driving schedules, SAE Paper No. 830304 (1983).Google Scholar

Copyright information

© Springer Science+Business Media New York 1997

Authors and Affiliations

  • F. Browand
    • 1
  • M. Zabat
    • 1
  • P. Tokumaru
    • 1
  1. 1.Department of Aerospace EngineeringUniversity of Southern CaliforniaLos AngelesUSA

Personalised recommendations