A Paoli father had no time to savor the progress he'd made on his Christmas shopping when a speeding red Honda rear-ended his car on Tuesday evening.

The Honda didn't stop.

Though dazed, Kevin Howell had the presence of mind to dial 911.

By Wednesday, his shopping still wasn't complete - but police were praising the 36-year-old computer programmer for helping them apprehend a hit-and-run driver they described as too drunk to stand up.

Howell said he was traveling about 60 m.p.h. in the left lane of the Exton Bypass to pass a tractor-trailer when the Honda Pilot crashed into the back of his Subaru Legacy.

Thus began a harrowing ride.

Howell said he witnessed a series of near-catastrophes as the out-of-control driver flouted late rush-hour traffic on the busy bypass.

"It was the scariest thing I've ever seen - bar none," Howell said Wednesday in an interview. "And I don't wish to repeat it."

West Whiteland Township Police Sgt. Martin J. Malloy said of Howell's actions: "His quick thinking and the ability to recover from the initial accident allowed him to follow the suspect and provide our dispatch center with updated information so that this dangerous driver could be taken off the road."

Malloy said William B. Borrell, 40, of Coatesville, was arrested for suspected drunken driving. He said Borrell, who was also charged with operating a vehicle without a valid license, reeked of alcohol, and was apparently so inebriated that officers could not perform field sobriety tests.

Borrell could not be reached for comment.

"He couldn't even stand up without assistance," Malloy said.

Court records show that Borrell pleaded guilty in 2001 to driving under the influence almost exactly a decade ago, on Dec. 29, 2000.

Only in the rarest circumstances do police recommend that ordinary citizens pursue suspects in a crime, Malloy said.

"As long as the driver is not endangering himself or anyone else, it can be helpful," he said - adding that without Howell's call, Borrell might have eluded police since he changed his direction of travel.

Howell said he had just finished shopping for his three children, ages 2, 4, and 6, about 6:15 p.m., and was getting ready to look for a gift for his wife when he was "rocketed forward."

"The next thing I know, I'm on the shoulder, facing sideways," Howell said. "I remember my head whipping back."

Realizing that the other driver was not stopping, Howell said he was relieved to find that he was still able to drive his damaged Subaru.

"I wanted to get his tag number," Howell said.

Howell said he caught up with the red Honda at a traffic light at the Route 100 exit of the bypass. But when the light turned green, Howell said, the Honda took off, running over a road sign, and blowing out a tire before careening up the westbound ramp - and into the stream of traffic on the bypass.

"It was crazy; he was all over the place," said Howell. "I had my flashers on and was beeping my horn to try and alert people."

About a half-mile from the Downingtown exit, Howell said, the Honda pulled onto the shoulder, went into reverse, and parked - across the traffic lanes, broadside to the oncoming traffic. Motorists frantically veered to avoid the car.

Howell was happy to see three West Whiteland police officers arrive.

After he shared his information with the police, Howell said "the adrenalin wore off" - and he realized his back, neck, and shoulders ached. He arranged to meet his wife at Paoli Memorial Hospital to get checked out.

"The nurses gave me a hard time about leaving my wife's present till last," he said.

He said he was glad no one else was hurt. "Thank goodness it wasn't worse," Howell said. "I hope people will think twice about drinking and driving."

Contact staff writer Kathleen Brady Shea at 610-696-3815 or kbrady@phillynews.com.