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A combination of metal roof passenger vehicles, an open top convertible passenger vehicle and enclosed multiple purpose utility vehicles were subjected to tip-over-the-front-end type pitch-over tests. The resulting roof crush and occupant compartment intrusion are presented in empirical and pictorial format. The tip-over roof crush performance is discussed relative to other recent side-over type rollover literature and to the FMVSS 216 on Roof Crush Resistance for Passenger Cars.

This paper is the third part of a series of vehicle tests designed and conducted in order to further the understanding of vehicle handling and responses associated with a tire disablement event. The first two parts were published in SAE 970954 Drag and Steering Effects of Under Inflated and Deflated Tires [1], and SAE 1999-01-0447 Drag and Steering Effects from Tire Tread Belt Separation and Loss [2]. All of the test results included herein are presented in a manner to facilitate direct comparison to the previous test programs. Under inflated or deflated tires are known to cause increased forward drag and lateral steering effects on vehicles. These effects are commonly suggested to be the cause of driver loss of control and subsequent vehicular accidents. The increased drag and induced steering effects of under inflated and deflated tires are frequently an issue in an accident reconstruction.

Tread belt separation and detachment is a common failure mode of radial tires. The accident reconstructionist is frequently asked to evaluate the effect of tread belt separation and detachment relative to the occurrence of an accident. Publications have previously been directed toward defining the effects of rapid tire deflation on vehicle drag and handling. However, little has been written about the singular effect of the loss of the tire tread belt relative to vehicle handling. The loss of a tread belt from a tire may be followed by rapid deflation. The combined separation and detachment event may have similar effects on vehicle handling as a rapid deflation event. To evaluate the effect of the loss of a tread belt without tire deflation, the authors tested tires prepared so that the tread belts could be intentionally separated while driving at speeds between 50 and 75 miles per hour.

Under inflated or deflated tires are known to cause increased forward drag and lateral steering effects on vehicles. These effects are commonly suggested to be the cause of driver loss of control and subsequent vehicular accidents. The increased drag and steering effects of under inflated or deflated tires are frequently an issue in an accident reconstruction. This paper documents the results of a series of tests conducted to determine the magnitude and effects of under inflated or deflated tires on cars and light trucks. The test also establishes a method of testing that can be used to determine steering effects for other vehicles and speed conditions. Six vehicles ranging from a compact passenger car to a 3/4 ton pickup truck were tested. The test methodology was simple and produced repeatable test results up to the 45 mph speed defined as a limit for the tests.