Yesterday's commute started routinely enough for Jonathan McBride. The Springfield man showed up at his Old Keene Mill Road "slug" line at 7:30 a.m. and a late-model sport-utility vehicle was waiting--stranger at the wheel--to give him a lift to work.

McBride, 30, knows the drill: He and other "slugs" get a free ride; in exchange, the driver gets to use Shirley Highway's car-pool lanes.

So McBride climbed in, nodded at the driver, barely acknowledged the woman in the back seat, and settled in for the 15-minute ride to the District. Sitting in the front passenger seat, he quickly buried himself in the sports pages.

Five minutes into the trip, something felt wrong, he later said, describing how he looked up just in time to see the SUV drifting off the right side of the roadway, inches from slamming into the concrete wall.

McBride looked over to see the driver slumped in his seat, unconscious.

Instinctively, McBride grabbed the wheel and turned it the opposite direction. The hulking SUV, which was going about 65 miles an hour, veered to the left, lunging across both lanes, and was again about to hit a wall when McBride swung the wheel and got the vehicle back on the road.

A terrified McBride and the woman in the back seat then realized that the driver's foot was still pedal-to-the-metal on the gas and that the SUV wasn't slowing down.

"Do something! Do something!" she shrieked.

"I'm trying! I'm trying!" he responded.

As McBride recounted the story, he shook the driver, but got no response. He thought the driver was dead, maybe from a heart attack. His concern quickly turned to his own fate. Do something now, he thought, or there will be two more dead people on this interstate.

With his left arm on the wheel, he unhitched his safety belt and climbed onto the slumped driver's lap. He frantically tried to reach the brake with his foot, but the driver's legs were in the way, and in the tangle of limbs, the car just went faster. Realizing he had only seconds to react, McBride knew he had to try something else, but what?

As the vehicle sped under the Seminary Road overpass, McBride scooted back into his seat and pulled hard on the automatic gearshift. The SUV lurched into reverse for a second before bouncing into neutral. Gradually, it began to slow.

It was still going about 45 mph, with McBride desperately searching for its hazard lights and a place to pull over, when the driver unexpectedly opened his eyes.

"Where am I?" he asked.

"On I-395 heading to Washington, D.C.," he was told.

"What happened?"

"You passed out."

McBride said the driver shook himself, put the car in gear and revved it back up to 65. As quickly as the routine commute had turned into a careening death trip, it was seemingly back to normal again.

From the back seat came the gentle suggestion that maybe McBride should drive now. That's okay, the driver said.

As the ride continued, the groggy man apologized repeatedly, saying this had never happened before. He mentioned long work hours, medication he's taking--and said he recalled feeling a little dizzy shortly after picking up the two riders.

"Sir, maybe you should have told us," the woman in the back seat chided him.

As the SUV crossed Memorial Bridge, McBride began to tremble, realizing how close a call they'd just had. What if he'd fallen asleep, like he often does during rides to work? What if he hadn't looked up? What if there had been cars all around as they bounced back and forth?

"I know that it was God that watched over us," said McBride, who--close call notwithstanding--has no plans to change his "slug" habits. When he got to work yesterday at the Department of Veterans Affairs, McBride said that he called Virginia State Police and that a surprised dispatcher told him his actions were "very heroic."

The trip ended when the driver pulled over at the corner of 18th and G streets Northwest and the two riders got out. The driver, whose name they never got, said he'd be fine, that he had only a little way to go. The woman turned, gave McBride a hug and thanked him. And, without even exchanging names or numbers, they went their separate ways.

CAPTION: Jonathan McBride, right, had to stop an SUV from crashing after the driver passed out.