On
August 20, 2010, NHTSA published a notice in the Federal Register at 75 FR
51521 announcing publication of a Technical Report, The Effectiveness of ABS in
Heavy Truck Tractors and Trailers. The
primary findings of the report are the following:
1) The best estimate of a reduction by ABS on the tractor
unit in all levels of police-reported crashes for air-braked tractor-trailers
is 3 percent. This is based on data from seven States and controls for the age
of the tractor at the time of the crash. This represents a statistically
significant 6-percent reduction in the crashes where ABS is assumed to be
potentially influential, relative to a control group, of about the same number
of crashes, where ABS is likely to be irrelevant.
2) In fatal crashes, there is a non-significant 2-percent
reduction in crash involvement, resulting from a 4-percent reduction in crashes
where ABS should be potentially influential. The age of the tractor at the time
of the crash is not important. Rather, external factors of urbanization, road
speed, and ambient lighting are influential and are accounted for in the final
estimate.
3) Among the types of crashes that ABS influences, there is
large reduction in jack-knives, off-road over-turns, and at-fault involvements
in collisions with other vehicles (except front-to-rear collisions).
Counteracting are an increase in the number of involvements of hitting animals,
pedestrians, or bicycles and, only in fatal crashes, rear-ending lead vehicles
in two-vehicle crashes.
Comments on the report are due to NHTSA no later than
December 20, 2010.
Docket ref: NHTSA-2010-0116.
NHTSA contact: Charles Kahane, 202-366-2560.