We've all seen —— and cursed -- drivers who jump into exit lanes not to leave the freeway but to zip around a line of traffic and then wedge their way back in.

Brakes screech, road rage looms and crashes can happen as those pretending to exit barge their way back onto the freeway. Sometimes those in the slow lane close the gap and refuse to let them back in.

It's not a new problem, but as traffic delays increase in the Bay Area it seems to be an increasing one. Complaints have roared into the Mercury News' Roadshow line over the past several weeks, and the California Highway Patrol says this is a now a problem it sees far too often.

"This ticks me off as well," CHP Officer Art Montiel said.

Pick an exit. Almost any exit.

Santa Rita Road and Hacienda Drive to Interstate 580 in the Livermore Valley. Wilder Road to Highway 24 before the Caldecott Tunnel. Third Avenue off Highway 101 along the Peninsula. Bascom Avenue and The Alameda off I-880 in San Jose. McKee Road at 101 in East San Jose. El Monte Road and I-280 near Los Altos.

Peta Grimes, of Livermore, calls drivers who pull this stunt "wolves desperate to gain a few car-lengths and who then force their way back in among the lambs, disrupting the whole flow of traffic."

Mary Fleck, of San Mateo, calls them "crazy drivers."

A.J. Young, of Dublin, labels them "cheaters" and says their numbers are increasing at 580-680. "I'd say 25 percent of the cars using the offramp are actually not exiting 580. Even on the weekends, when traffic is light."

It is illegal if there are black and white signs saying drivers must exit (Bascom Avenue and I-880). You must get out of that lane by the time you drive by the sign. The fine is around $250.

But at some interchanges without those signs, it is legal if done safely (Wilder Road at 24 and Tully-101 and Highway 17 north before Highway 85). Irritating, certainly, but legal.

"Unfortunately, this occurs way too often and only gains the violator about 30 seconds," said CHP Officer Chris Falkowski. "Not only is it frustrating for the other motorists, but it is unsafe for everybody."

It's unsafe because these exit-lane cheaters often have to throw on the brakes to merge back into freeway traffic, and sometimes they'll come to a complete stop to do so. These actions can cause worse backups, not to mention collisions.

That's what happens at Camden Avenue and Highway 85 in San Jose, said Brenda Dutkiewicz.

"The result is angry motorists on northbound 85 not happy or willing to let the cheaters in and many close calls for exiting motorists as they stomp on the brakes to prevent rear-ending stopped cars trying to re-enter traffic. I am shocked there have not been more accidents or complaints. There are a lot of skid marks to show for it."

Chuck Martin, of San Francisco, got a huge scare recently on 101 near Hillsdale Avenue. A bus taking workers to Silicon Valley moved into the exit lane.

But the bus didn't exit. It moved back onto 101 in front of him.

"That's at least bad, antisocial behavior," Martin said.

Freeways across Northern California are being widened to add more auxiliary lanes, the kind that begin at one onramp and end at the next offramp.

This work is going on along 101 north of the 85 interchange in Mountain View, on Highway 1 through Santa Cruz, along I-680 through Walnut Creek and at I-580 in Livermore.

Most will have "RIGHT LANE MUST EXIT" signs.

Heed them, please.

"Those signs are there for a reason," said Montiel.

Contact Gary Richards at 408-920-5335.