VEHICLES-IN-USE SUB-LIMIT MANEUVERS. VOLUME I: EXECUTIVE SUMMARY

The report presents results of a test program to validate applicability of six previously developed maneuvers in determining the influence of vehicle-in-use steering, suspension, and brake system degradations and tire factors on vehicle sub-limit handling. Six vehicles were tested which reflect subsystem design features and class size ranges representative of the majority of domestic and foreign vehicles-in-use in the United States. Test results show the maneuvers and procedures consistently produced measurable performance differences for the types and levels of subsystem degradations employed. The major handling detriment observed is nonlinear or discontinuous response for normal driver inputs (steer, brake, or throttle) which occurred for certain component degradations and vehicle acceleration levels. The tests also included an investigation into the influence of sagged coil springs and coil spring spacers on handling performance of two full-sized automobiles. The findings relate vehicle stability factor (a measure of the basic understeer intentionally designed into the vehicle steering and handling characteristics) and controllability with change in ride height, sprung mass roll axis, and suspension bump-stop bottoming. Results show consistent and measurable differences in handling parameters, depending upon location of sagged spring and use of spring spacers. The least desirable situation is asymmetric (i.e., one side only) sagged spring and spacer usage which produces different handling response in left versus right maneuvers and can lead to vehicle controllability problems.

• Supplemental Notes:
  • Volume 2 PB81-159519 is HS-805 698 and Volume 3 is HS-805 700. Also available in set of 3 reports PC E11, PB81-159493.
• Corporate Authors:

  Systems Technology, Incorporated

  13766 South Hawthorne Boulevard
  Hawthorne, CA  United States  90250

  National Highway Traffic Safety Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Johnston, D E
  • Mitchell, D G
• Publication Date: 1980-9

Media Info

• Features: References;
• Pagination: 30 p.

Subject/Index Terms

• TRT Terms: Automobiles; Brakes; Braking; Driving; Dynamic loads; Handling characteristics; Motor vehicles; Performance evaluations; Spacing; Springs (Vehicles); Stability (Mechanics); Steering; Structural members; Subsystems; Suspension systems
• Uncontrolled Terms: Dynamic response; Lateral stability
• Old TRIS Terms: Helical springs; Spacers; Steering control
• Subject Areas: Highways; Vehicles and Equipment; I91: Vehicle Design and Safety;

Filing Info

• Accession Number: 00329071
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: TR-1119-1-I Final Rpt., HS-805 697
• Contract Numbers: DOT-HS-7-01799
• Files: HSL, NTIS, TRIS, USDOT
• Created Date: May 21 1982 12:00AM