Last week, Washington Post reporters and editors became commuters and raced each other by car and public transportation along several typical commuting routes. Today's report compares commuting by car, car pool, bus and subway along Northern Virginia's heavily traveled Shirley Highway.

Start: 8:05 a.m. at the intersection of Spring Mall Drive and Frontier Drive on the southeast corner of Springfield Mall shopping center.

Finish: Washington Post Building at 15th and L Streets NW in downtown Washington.

Car pool on Shirley Highway express lane: 25 minutes.

Car and Metro subway: 43 minutes.

Car (single occupant) on Shirley Highway: 47 minutes.

Metrobus and subway: 51 minutes.

The sky was clear blue, the sun hazy and there was a rosy glow on the horizon as the four of us set out from Springfield Mall.

As we entered the Shirley Highway express lane for car pools and buses - designated by big black-and-white signs at the Turkeycock ramp just past Edsall Road - someone wondered aloud about the penalty for driving in the car pool lane without four riders. "It's $10 and a moving violation," said a passenger in back, who had been nailed for driving in the express lane with just two people in a two seater-sports car.

Soon after we got into the car pool lanes, we noticed a police car, apparently there to catch cars with too few riders. The other cars in the car pool lanes passed us; they must have been driving over the speed limit.

By 8:20, we could see the Pentagon on the left and traffic at a standstill in the regular Shirley Highway lanes on our right. We measured the backup at 1.7 miles from the Pentagon to the 14th Street bridges.

We breezed right on through, up 14th Street NW and over to The Post, where we parked in the Post Employees' parking lot (cost: $37 per month).