Excessive speed and a man asleep at the wheel of his car are being blamed for two motorcycle crashes over the weekend.

The first of the two accidents happened Saturday morning in Saco. Public Safety spokesman Steve McCausland says 42-year-old Diane Sprague was seriously injured in a freak accident on the Maine Turnpike in Portland. She was a passenger on a motorcycle when it collided with debris from a car that struck a concrete barrier. Police say the car's driver, 22-year-old Norman Watson of Windham, fell asleep while traveling in the northbound lane. The impact of the car hitting the concrete ripped the front bumper off the car, which then flew into the path of the bike. The motorcycle operator, 46-year-old Ronald Boucher of Saco, had minor injuries. The northbound lanes of the turnpike were closed for four hours after the crash.

The second accident happened Saturday night in Hollis. McCausland says 37-year-old Michael Gemmell was allegedly speeding when he lost control on the Bonny Eagle Road just after 7:30 and the bike overturned. Police say he suffered multiple injuries when he was thrown from the motorcycle and was transported to Maine Medical Center.