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Essays:
Avoidance Maneuver Accelerations


While reviewing some old driver performance data in SAE 766060, I turned up a collection of lateral accelerations generated by people who were driving along at 50mph and had a box dropped in the road in front of them. The average of the 61 tests was 0.44 g's, with a standard deviation of 0.14. That means that a 5th percentile driver generated about 0.15g's. while a 95th percentile person generated 0.72g's.
histogram of 766060 data

These values are somewhat higher than reported by some researchers, but lower than we found sheriff's department employees were willing to use during navigation through a closed-course which included some hard turns, and a 30mph (approx) slalom, as shown here first for the Chevy Caprice, and then the Chevy Lumina:
histogram of Caprice data in 2000-01-0179

histogram of Lumina Data from 2000-01-0179

The vintage of the 766060 data leads me to wonder if modern grippier tires, tighter suspensions, and more powerful power steering pumps might allow people to generate higher values.

It has been shown that people are willing to generate 200 degrees of steering wheel rotation during avoidance maneuvers, which can result in lateral accelerations similar to those we found on the test-course. (Kazuo 1990, Arndt, 1999)

Other References
    Review and Correlation of Driver/Vehicle Data Weir, McRuer, SAE paper 766060, 1976
    Driver capabilities in closed course testing Bartlett, Wright, Masory, SAE 2000-01-0179
    Driver's response and behavior on being confronted with a pedestrian or a vehicle suddenly darting across the road SAE 900144, Kazuo Araki and Yuzuru Matsuura
    Influence of passenger and cargo load on the at limit handling of a mini van Arndt, et al, SAE paper 1999-01-0449
    Review of relationship between steering wheel reversal rate and driving task demand Macdonald, W.A. & Hoffmann, E.R. (1980). Human Factors, 22, 733-739.
    Analysis of drivers' control movements McLean, J.R. & Hoffmann, E.R. (1971). Human Factors, 13, 407-418.
    Steering reversals as a measure of driver performance and steering task difficulty McLean, J.R. & Hoffmann, E.R. (1975). Human Factors, 17, 248-256.

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This page last modified 10-FEB-2001