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Status Report, Vol. 45, No. 3 | March 31, 2010 Subscribe

Antilock brakes on motorcycles prevent crashes

The best motorcycle crash is the one that never happens. One technology designed to reduce the chance of crashing is antilock braking. The Institute first reported on the effectiveness of motorcycle antilocks in 2008 (see "Antilock brakes on motorcycles reduce both crash frequencies and deaths," Oct. 22, 2008). Now 2 new studies, one by the Institute and one by the affiliated Highway Loss Data Institute (HLDI), provide more evidence that antilocks reduce fatal crash risk and lower insurance losses.

Stopping a motorcycle is trickier than stopping a car. For one thing, the front and rear wheels typically have separate brake controls. In an emergency, a rider faces a split-second choice to either brake hard, which can lock the wheels and cause an overturn, or hold back on braking and risk running headlong into the emergency. This is when antilocks can help by reducing brake pressure when they detect impending lockup and then increasing the pressure again when traction is restored. Brake pressure is evaluated multiple times per second, so riders may brake fully without fear of locking up.

Antilocks won't prevent every motorcycle crash. They won't help a rider who's about to be struck from behind, for example. But the new studies indicate that antilocks reduce crashes overall and save lives.

Institute researchers compared the fatal crash experience of antilock-equipped motorcycles against their nonantilock counterparts during 2003-08. The main finding is that motorcycles with antilocks versus without are 37 percent less likely to be in fatal crashes per 10,000 registered vehicle years. Bolstering this finding is a separate HLDI analysis of insurance claims filed for damage to motorcycles. Bike models with antilocks have 22 percent fewer claims for damage per insured vehicle year than the same models without antilocks.

Drivers younger than 25 have the highest estimated claim frequencies. Where motorcyclists ride also affects claims. The frequency of claims for crash damage to bikes is 9 percent higher in urban areas with heavy traffic than in moderately congested locales. There were 13 percent fewer claims in the least populated areas than in medium-density ones. The effects of antilocks on claims were estimated only after controlling for these and other factors.

Antilocks are gaining traction among motorcycle manufacturers and wider acceptance among riders. More than half of motorcycle owners recently surveyed by the Institute said they'd get antilocks on their next bike. Buyers can find them now on at least 60 new models.

"Motorcycle antilocks do make a difference," says Institute president Adrian Lund, who also is president of HLDI. "They help make traveling on 2 wheels less risky by reducing the chance of overturning a bike and crashing. Passenger vehicles still are safer, but if you're going to ride we'd recommend getting a motorcycle with antilocks."

HLDI also looked at injury claims. Under medical payment coverage, motorcycles with antilocks registered 30 percent lower claim frequencies than bikes without this feature. Claim frequencies were 33 percent lower under bodily injury liability coverage.

Institute researchers used data from the federal Fatality Analysis Reporting System and motorcycle registration records from R. L. Polk and Company. HLDI provided antilock feature information from its proprietary database of vehicle features.

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