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Performance Margin for Geometric Road Design

Journal Article
06-11-04-0022
ISSN: 1946-3995, e-ISSN: 1946-4002
Published August 08, 2018 by SAE International in United States
Performance Margin for Geometric Road Design
Sector:
Citation: Kang, Y. and Ferris, J., "Performance Margin for Geometric Road Design," SAE Int. J. Passeng. Cars - Mech. Syst. 11(4):263-272, 2018, https://doi.org/10.4271/06-11-04-0022.
Language: English

Abstract:

Although several methods exist for measuring the performance capability of a vehicle, many require detailed knowledge of the forces acting at each tire contact patch or do not account for both the vehicle dynamics and the road geometry. A simple vehicle model is proposed to estimate the upper limit of performance capability for a given operating condition (the Performance Envelope) based on the Effective Friction and the road geometry (slope and cross-slope). The Effective Friction accounts for both the vehicle dynamics and road surface properties and is estimated, through simulation or experimentation, using two standard vehicle dynamics tests: constant radius cornering and straight-line braking. The Performance Margin is defined as the additional performance capability available before the vehicle reaches the Performance Envelope, both represented in the intuitive units of gravity. The Performance Margin is applicable to both geometric road design and vehicle control; both of which are crucial as transportation agencies and vehicle manufacturers prepare for the introduction of autonomous vehicles.