Fitzhugh Newberns has seen people abandon their cars in a tunnel traffic jam and try to walk away. A woman stopped in front of Tom Smith and announced she was afraid to drive the rest of the way through the tunnel. Smith drove her out.

Newberns and Smith are tunnel workers, the people who man tunnel catworks, watching the traffic and waiting for trouble.

On holiday weekends, a lot of drivers spend more time than they want in tunnels. From inside their cars they complain about the traffic, check for symptoms of claustrophobia and exchange glances with people who really spend time in tunnels like Newberns and Smith.

The Lincoln Tunnel connecting idtown Manhattan and Weehawken, N.J., is perhaps the most heavily traveled roadway in the world.

Last year, 32 million vehicles used the Lincoln Tunnel and 6,000 of them broke down.

In each of the Lincoln's three two-lane tubes, two men are on duty waiting for the breakdowns.

The rest of the tunnel workers (for whom someone invented the title Facility Operations Agent) wait in the emergency garage at each end of the tunnel where they have custom-built wreckers that can turn in the narrow tunnel and still pull heavy tractor-trailers, firefighting equipment and jeeps.

The men (there is one woman FOA at the Holland Tunnel, but none at the Lincoln) preier garage duty to time in the tunnel.

"It can get pretty boring. On days when nothing's happening, then you go crazy," Smith said.

But, life in the tunnel doesn't dismay the generally young and enthusiastic FOA, who point out that it has been improved by a series of relatively new devices.

The FOAs are only a part of the tunnel traffic control system.The New York-New Jersey Port Authority, which owns and operates the Lincoln Tunnel, has pioneered the use of television cameras, vehicle detectors in the pavement and remote-controlled traffic signs.

Television cameras cover the length of all three Lincoln Tubes so the number of men on duty in each has been cut from six to two and the salary saving has more than paid for the new machinery, Port Authority officials said. No longer do the men have to walk the 1.5-mile-long catwalks, now they ride on tiny gasoline-powered monorial cars which go about 20 m.p.h.

In summer the tunnels still get very hot and the constant wind and noise created by the traffic are unpleasant, but the FOAS, whose starting salary is $15,000 a year, spend most of their waiting time in air-conditioned glass booths.

The first, Lincoln tunnel tube opened 40 years ago next month and those who remember its earliest years speak of traffic flow so slight that an hour could pass between one car and the next.

In those days and until 1973, the men on the catwalks were Port Authority police and the old-timers liked to tell stories of men writing poems, painting pictures and playing musical instruments on the catwalks during the early morning shifts when there was almost no traffic.

Now, about 95,000 vehicles pass through the tunnel daily and as many as 100 have broken down in a single day.

People who run out of gas or have flat tires or overheated engines in the tunnel often protest when they see the wrecker coming that they haven't any money, Smith said. But whether are being truthful or not doesn't matter. The tunnel provides one of the few free tows available anywhere.

The FOAs will also help an elderly person change a tire once they've pulled his or her car out of the tunnel, but they expect most people to change their own, Smith said.

About half the annual breakdowns in the tunnel come during peak travel hours, according to the port authority, so speed is a major goal of the FOAs in clearing a disabled car from the tunnel.

Last summer, the FOAs and the New York Fire Deapartment held a fire drill. At 5 a.m. one Sunday, they set a car afire in one of the closed-off tubes.

Alan T. Gonseth, the Lincoln Tunnel manager, is in charge of the overall traffic planning.Since the tunnel has three tunes, it can be switched to carry four lanes into Manahattan in the mornings and four lanes out in the evenings.

Gonseth and his staff also take account of sporting events at Madison Square Garden or the new football stadium in New Jersey called the Meadowlands in planning how many lanes should be open and which way they should run.

It takes between seven and 11 minutes to change traffic in one tube from one direction to the other, Gonseth said.

"The ideal," he said, "is to have congestion equal on each end so that everyone waits the same amount of time."

On a holiday or other expectably heavy day, Gonseth said, the tunnel will switch its lanes earlier, if people are leaving the city.

The ideal also is to keep traffic running close to the optimum level for the tunnel which tests have shown is a traffic stream at 30 m.p.h. with a density of 45 vehicles per mile.

At that rate, 1,450 vehicles pass through one lane per hour until one of them stops and the FOAs scramble their catwalk cars and wreckers to get the flow started again.