JACKSONVILLE, Fla. -

Two riders were killed in single-vehicle crashes overnight and a third motorcyclist was critically injured when a car pulled in front of his bike on Capper Road Friday morning.

William Cooper, 22, was riding north on Interstate 295 at a high speed about 10:30 p.m. Thursday when he lost control of his Suzuki, according to the Florida Highway Patrol. He was thrown from the motorcycle and died at the scene.

Just more than two hours later, 25-year-old Michael Johnston was riding north on the Acosta Bridge shortly after 1 a.m.

Map: 3 motorcycle wrecks in 11 hours Troopers said Johnston's Honda CBR-600 hit the barrier and he was thrown off the bridge onto the train tracks below. He died at the scene.

At 8:35 a.m. Friday, police said an elderly driver was pulling out of Florida State College at Jacksonville's parking lot onto North Campus Boulevard and didn't see the motorcycle approaching. He wasn't able to stop before hitting the Dodge Charger and was thrown onto the road.

The motorcyclist, a 39-year-old man whose name has not been released, was taken to UF Health Jacksonville with life-threatening injuries.

Police said neither the driver nor her 13-year-old granddaughter were injured.  The driver will be cited for failure to yield.

Two days ago, 47-year-old Steven Gott -- a zookeeper at Jacksonville Zoo and Gardens -- was killed when his motorcycle struck a railroad crossing arm down across Zoo Parkway for testing.

According to the Florida Highway Patrol, there have been 523 motorcycle crashes in Duval County since the beginning of 2013 -- 19 of those have resulted  in a death.

Across Florida, there have been 10,206 motorcycle crashes so far this year, and 349 of those were fatal.

"Motorcycles are hard to see, so based on their size and lighting equipment and so forth, it takes a second glance," FHP Sgt. Dylan Bryan. "Just want to remind the motoring public again to be observant when their operating their vehicles on the roadways, not only for motorcycles, but for other vehicles as well."