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Directions in Highway Safety, Fall 2007 Cover Page Download Newsletter pdf
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Fall 2007 | Vol. 10 | No. 3

Rusty Baby Boomers on Bigger Bikes: Is That What is Behind the Increase in Motorcycle Deaths?

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By: Scott R. Falb
Research & Driver Safety Analysis, Office of Driver Services
Iowa Department of Transportation

Motorcycle Fatalities in Iowa have risen 256% during the last 10 years. During that period of time motorcycle registrations only increased 36%. That follows 17 years during which the numbers declined for fatalities (-81%), injuries (-71%) and motorcycle registrations (-47%). A clear understanding of the nature and scope of the problem will hopefully lead policymakers to solutions.

Motorcycle Photo

Why is the rise in fatality numbers outstripping the much smaller increase in the number of registered motorcycles? The demographic changes may tell part of the story. The number of licensed riders hit its low point in 1997 at 213,626. By 2006 it had grown to 235,809, only a 10% increase, one-third the size of the growth in registered motorcycles. Young riders decreased 88% since 1977, while middle-age riders have increased 362% during the same period, and the number of riders aged 55-64 has increased 729%.

Motorcycle dealers report a surge in middle-age license holders returning to motorcycling, buying motorcycles after not owning for many years. Not only are baby boomers returning to cycling, but they are buying much bigger motorcycles than they owned when they were young. In the 1970's and early 1980's these (predominantly) young men owned small Japanese motorcycles in the 125cc to 450cc sizes. These now middle-age men are buying much larger Harley Davidsons and Hondas (1000cc to 1500cc). These two makes account for over two-thirds of the registered motorcycles in Iowa. Motorcycles with engine sizes of 1101cc to 1450cc were involved nearly half of all fatal crashes and nearly 40% of all crashes in 2006.

While Harley Davidsons (34% of total motorcycle registrations) were involved in the largest numbers in all crash severities, they only ranked third in crash rate (78.6 crashes per 10,000 registered motorcycles) in Iowa. Kawasaki (11% of total motorcycle registrations) and Suzuki (9% of registrations), who sell the so-called "crotch-rocket" models popular with young riders, had higher crash rates (79.3 and 83.9). Honda, whose Goldwing model is a popular touring motorcycle, had the lowest crash rate (41.8).

Half of the fatal crashes in Iowa were single vehicle crashes in 2006. In two-vehicle crashes, motorcyclists had contributing circumstances listed 64.3% of the time. The other motorist had contributing circumstances 39.3% of the time (in 3.6% of the crashes both drivers contributed). For the motorcyclist, speed (56%) and loss of control (54%) are noted as contributing in nearly half of the crashes, while alcohol and drugs occured in nearly one-third of fatal crashes.

Motorcyclists not wearing a helmet also contributed to the extent of injury in Iowa motorcycle crashes. Iowa conducts a helmet survey each summer in conjunction with a comprehensive roadway traffic count survey. The average usage rate for this survey was 30%. Iowa is one of three states without a mandatory helmet law. In all traffic crashes, for 2005, the helmet usage rate was 27%. Only 15% of those killed in fatal crashes in Iowa wore a helmet.

According to data from the Iowa Crash Outcome Data Evaluation System (CODES), the injuries suffered by motorcyclists who do not wear a helmet are more severe and take longer to heal on average. Unhelmeted riders made up 84% of all hospitalized motorcycle riders, and 93% of hospital charges were incurred by unhelmeted riders. These riders' average hospital charges are more than double the average costs of helmeted riders, and unhelmeted riders are more likely to require rehabilitation or long term care following release from the hospital.

It is sad to say that these kind of numbers are continuing in 2007. As of August 31, Iowa had 50 motorcycle fatalities, at least 9% higher than at this time in 2006. Onethird of the drivers involved fatal motorcycle crashes were age 45-54. More than three-quarters of the fatal motorcycle crashes were single vehicle crashes (64% overturn and fixed-object crashes and 13% deer crashes), while only 23% involved another vehicle.