Killer ABS

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Killer ABS

By Frank Williams

August 14th, 2006 1,656 Views

 

The National Highway Traffic Safety Administration

(NHTSA) has a mission: “Save lives, prevent injuries,

reduce vehicle-related crashes.”

NHTSA also commits itself to “providing the most

accurate and complete information available to its

customers, the American traveling public.” While

NHTSA’s progress towards its stated goals is (and

always will be) a matter of debate, the agency has

failed us. They’ve failed to tell the truth about ABS.

 

 

Modern ABS consists of a computer (CPU), four speed

sensors (one on each wheel) and hydraulic valves

(attached to the brake circuit). When the CPU senses

that one or more of the wheels are turning

significantly more slowly than the others, it

decreases the pressure on the braking circuit. If the

wheel or wheels then turn too fast (freed from

braking), the force is reapplied, creating a pulsing

sensation through the brake pedal.

 

When Bosch’s Antiblockiersystem appeared on the US

automotive scene in the late ‘70’s, safety advocates

hailed electronically assisted braking as a

life-saving technology that would reduce the number

and severity of accidents. Tests under controlled

conditions seemed to support the contention. NHTSA and

the insurance industry quickly embraced and promoted

the technology.

 

Thanks (in part) to insurance industry discounts,

almost every passenger vehicle now sold in America is

fitted with ABS. NHTSA’s web site proclaims “…an

antilock brake system (ABS) is a safe and effective

braking system. ABS allows the driver to maintain

directional stability, control over steering, and in

some situations, to reduce stopping distances during

emergency braking situation, particularly on wet and

slippery road surfaces.” The real-world evidence

doesn’t support their claims.

 

Researchers have compared accident and fatality rates

for vehicles with and without ABS. Other studies have

examined the driving records of ABS and non-ABS

equipped taxi drivers in Munich and Oslo. The accident

and fatality data shows that ABS exacerbates the

severity of accidents in certain situations. The taxi

study proved that drivers tend to take greater risks

in cars equipped with ABS (although the difference in

collision rates was not significant). In short, ABS

may do more harm than good.

 

More specifically, the studies show that ABS has no

real-world effect on dry-surface braking, ABS-equipped

vehicles take longer to stop on ice than non-ABS

vehicles, ABS-equipped vehicles are more prone to

roll-over accidents than non-ABS vehicles,

ABS-equipped vehicles are involved more often in

single car fatal accidents than non-ABS vehicles, and

drivers of ABS-equipped vehicles tend to drive faster

and apply their brakes later than non-ABS drivers.

 

The AAA Foundation for Traffic safety has determined

that improper driver steering in an ABS-equipped

vehicle can send it veering out of control. In their

tests, jerking the wheel (as if trying to steer around

an obstacle) in a 35 mph panic stop sent ABS-equipped

cars careening across two lane widths. (Without the

ABS, the car skidded in a straight line.) This

behavior may account for the higher roll-over rates

for ABS-equipped vehicles. Other research revealed

that many drivers don’t use ABS properly; they pump

the pedal as they would regular brakes.

 

NHTSA, the insurance industry, manufacturers and

engineers are all well aware of ABS’ shortcomings. In

1994, Dr. Charles J. Kahane published a paper for

NHTSA entitled “Preliminary Evaluation of the

Effectiveness of Antilock Brake Systems for Passenger

Cars. " Kahane reported that “All types of run-off-road

crashes - rollovers, side impacts with fixed objects

and frontal impacts with fixed objects - increased

significantly with ABS. Nonfatal run-off-road crashes

increased by an estimated 19 percent, and fatal

crashes by 28 percent.” Kahane also concluded that

“Rollovers and side impacts with fixed objects… had

the highest increases with ABS. Nonfatal crashes

increased by 28 percent, and fatal crashes by 40

percent.”

 

In 1996, the Insurance Institute for Highway Safety

published a news release titled “Antilock Brakes Don’t

Reduce Fatal Crashes; People in Cars With Antilocks at

Greater Risks- But Unclear Why.” In 1998, Leonard

Evans of General Motors’ Global R & D Operations checked

NHTSA’s ABS crash data and concluded “it is unlikely

that on dry roads ABS can materially reduce risk” and,

more shockingly, “ABS is associated with a 44%

increase in rollover risk.” In 1999, the Society of

Automotive Engineers reported that “ABS was found to

be associated with a 51 percent increase in fatal

rollover crashes on dry roads. For fatal side impact

crashes, ABS produced a 69 percent increase for

unfavorable road conditions, and a 61 percent increase

for favorable road conditions.”

 

The average cost of an ABS system is $240. Multiply

that figure by millions of vehicles, add the number of

lives lost and the injuries suffered because of ABS'

ill effects, and the true cost of this potentially

lethal braking systems is evident.

 

At the very least, NHSTA should launch an immediate

investigation into the advisability of fitting SUV’s

with ABS.

Meanwhile, you’ve been warned: ABS can kill.

 

http://www.thetruthaboutcars.com/?p=2006