Four people were killed within an hour in Loudoun County on Sunday morning in two separate traffic crashes. Two people died in each of the incidents.

In the first, which occurred about 12:40 a.m., a car and motorcycle collided on Ashburn Farm Parkway, the county sheriff’s office said. The car was turning into a shopping center, according to the sheriff’s office.

The motorcycle driver and passenger, both from Ashburn, were killed, the sheriff’s office said. Neither has been identified yet.

The car’s driver was identified by the sheriff’s office as Mark Sgarlata, 52, of Ashburn. He was charged with driving under the influence, the sheriff’s office said.

The second double-fatal crash occurred about 1:40 a.m. near Evergreen Mills and Reservoir Roads in the Leesburg area, the Virginia State Police said.

They said an SUV came through a curve on Evergreen Mills Road in the Leesburg area. It crossed the center line, ran off the road and slid into a tree, police said. The vehicle caught fire and both occupants died, the office said.

Police withheld their names pending notification of relatives. Speed was a factor, police said.

Authorities said both incidents remained under investigation.