Before anything else, understand that the Roads Scholar does not advocate speeding or breaking any other traffic laws.

But we do prefer those laws to have some basis in reality, which Newton's John Carr proved is not the case with the 45 mph construction speed limit on the Pike Extension from Weston to Boston.

"I tried an experiment. I attempted to obey the law," Carr said of a recent trip in with his cruise control set at 45 mph.

His intended destination was MIT, via Exit 18 for Cambridge on the left side of the highway.

But to get there he'd first have to get out of the right lane, which was a problem because cars in the other lanes weren't going 45.

"I measured it a couple of years ago. The average speed coming into Boston was 67," Carr said.

At Exit 18, he said, "It was impossible to safely change lanes, and speeding up to merge safely was illegal. So I missed my exit."

Undaunted, Carr figured he could still take the I-93 north tunnel to Storrow Drive and head back west. But cars weren't going any slower as he approached that exit, and if he stayed right, he'd end up at Logan or Revere.

So he sped up to 55 to make the merge and broke the law.

State police Maj. Michael Mucci said he'll get a pass.

"We're doing everything we can in regards to traffic," Mucci said, noting the numerous speed-limit signs and a plan to have a cruiser, lights flashing, loop around the extension at slow speed.

Like 45 mph?

"Well, no. They're not going that slow," he admitted.

The problem, he said, is there's no place for cruisers to pull anyone over because of the narrow construction zones. Even the breakdown pullouts have been cordoned off, which Pike engineers explain is because there's no longer room to open your car door without someone smashing into it.

"I'm sure we're not going to be stopping anyone going (under) 60," Mucci said.

Carr says that's pointless. "If we can go 55, then admit it."

Both Carr and Mucci noted cars seem to speed up when they get closer to the city, by the way.

"There's some road Web site I went to that describes it as the gravitational attraction of Boston," said Carr, whose major at MIT was planetary science.

So that's what's wrong - it's not the rules of the road on the Pike, it's the laws of physics.

Got a commuting gripe? Write to the Roads Scholar at rwashington@bostonherald.com.

© 2004 Copyright by the Boston Herald.