The death of a 40-year-old Mount Pleasant woman whose motorcycle crashed on a freeway onramp Tuesday highlights two trends in fatal two-wheeled crashes — increases among women and older riders.

Marque Thompson was riding a brand-new Kawasaki Ninja when it smashed into a barrier around 6:30 p.m., authorities said. The crash sent Thompson from the bike off a 33-foot drop near the convergence of the Mark Clark Expressway and Interstate 26.

The crash came as motorcycle fatalities have been rising in South Carolina and in the nation, even more so among women and riders over 35.

Authorities have been pushing motorcycle safety courses as a way to curb the trend.

In 1999, four of the 66 motorcycle riders who died in South Carolina were women. By 2005, the latest year for which statistics are available, 11 of 83 of the state's motorcycle fatalities were women, meaning the rate doubled, from about 6 percent to 13 percent.

Meanwhile, riders are aging. Motorcycle ownership rates among baby boomers increased 44 percent between 1990 and 2003, compared with only 6 percent for non-baby boomers.

"The largest growing part of the industry (of buying new motorcycles) now is females," said Ross McClellan, who coordinates the South Carolina Technical College System Motorcycle Training Program. "The average age of a female taking a class is around 41 and the average male around 38."

McClellan said women have gone from about 2 percent of the new motorcycle market just a few years ago to more than 15 percent now.

Every five years, the mean age of motorcyclists increases by a year, McClellan said.

Much of the blame for serious accidents, however, lies with car and truck drivers, not the bikers, Department of Public Safety spokesman Sid Gaulden said; 30 percent to 40 percent of fatalities are not the motorcyclist's fault.

In May, U.S. Secretary of Transportation Mary E. Peters called on manufacturers to provide free or heavily discounted DOT-certified helmets or rider-safety training with the purchase of every new motorcycle sold in the U.S.

She noted that motorcycles account for only 2 percent of the vehicles on the road but more than 10 percent of all crashes. She added that motorcycle fatalities have more than doubled in 10 years and now account for more than 4,500 highway deaths and 78,000 injuries each year. Even worse, the crash rate among motorcyclists in the 50-plus age group has increased by more than 400 percent, she said.

For now, riders can take courses at technical colleges all over South Carolina. McClellan, who coordinates the program at the state level, advises, "Take a rider education course before you buy."