ABS Failure

Incorrect Installation Causes Car Accident

Omaha, NE

Background: The vehicle involved in this accident had been professionally repaired, and had incorrect rear hub carriers and ABS sensors installed. When the accident occurred, the driver reported that the brakes did not work.

What We Did: To analyze the accident, an exemplar vehicle was procured and new sets of correct and incorrect hubs were purchased. Using both hubs, full-scale vehicle testing was conducted on an airport runway. After instrumenting the vehicle, CAN bus wheelspeed data showed that although the two types of hubs appeared to be identical, small differences in construction and electrical components indeed rendered the brakes inoperable when the incorrect hubs were installed. Exemplars of both hub types were machined and painted to highlight differences for use as trial exhibits.

Relevant Scientific Publications:

Metz, L. D. & Schiebe, R. R., “Use of ABS in Emergency Brake-and-Steer Maneuvers” SAE Paper No. 2009-01-0449 (2009).

Metz, L. D. & Meyers, D. R., “Controlled Braking Experiments with and without ABS,” SAE Paper No. 2010-01-0100 [also in SAE SP-2261](2010).

Exemplar rear hub showing ABS sensor.

Exemplar rear hub.

Exemplar rear hub carrier.

A fool knows the price of everything and the value of nothing.

Milton Friedman, economist/Nobel Prize winner