An unknown motorist hurtled west along Interstate 70 outside of Glenwood Springs early Friday morning, driving a dark-colored, older-model Mustang so fast that state troopers couldn’t get a read on its license plate.

The driver was going 140 mph on a stretch of Interstate 70 about 10 miles west of Glenwood Springs where speed limits drop to account for long, hazardous curves as the highway follows the contours of the Colorado River.

Instead of slowing down after troopers turned on their sirens and lights, the person driving the Mustang accelerated to 150 mph, Colorado State Patrol spokesman Trooper Gary Cooper said

“They tried to catch up. They weren’t doing it,” Cooper said. “They couldn’t get close enough.”

Whoever it was going more than twice the speed limit at 12:30 a.m. was risking their life, so troopers decided not to risk theirs and called off the chase, Cooper said.

“It’s extremely reckless, especially with people who haven’t been trained to drive at those speeds,” Cooper said. “I’ve seen a deer total a car before.”

Brakes get hot and tires can suddenly blow out at high speeds, he said. Calling off the chase in this circumstance may have saved the life of the driver, he said.

UPDATED: This story was updated at 12:54 p.m. on March 30, 2018, to correct the location of the chase.