The single leading killer of U.S. servicemen so far in the gulf war isn't Iraqi Scud missiles, long-range artillery, or even the nightmare of so-called "friendly fire."

Far more low-tech and closer to earth, it's a daily threat with which all Americans are intimately familiar: traffic accidents.Just like their civilian counterparts, the dirt roadways cut throughout northern Saudi Arabia are both a deadly, and an essential, part of everyday life.

The roads run from one horizon to the next, marked by Spartan borders of foot-high plowed dirt and an occasional cardboard marker on a wooden post. They tie together row upon row of bunkered military camps that dot the dry dusty landscape like huge anthills.

There's no time in the rush of war for pavement. There are few road signs and no thought of street lights, lane markers or cops.

Constantly running their hours-long routes is an army of highly energetic and anxious young men rushing to fill their camps with food, tents, machinery and weapons.

At least one result is predictable.

After some six months of operations Desert Shield and Desert Storm, 117 servicemembers had died as of Tuesday. Accidents accounted for 88 of those, and of those 33 were vehicular.

"It tells me that the guys need to slow down," said Navy Master Chief Jack Mitchell, 45, who heads up a team of construction workers.

The Seebees, whose nickname comes from the initials for Construction Battalion, are among the least glamorous of America's fighting men and women. But their work is crucial to all the rest.

In their few short weeks of work along Saudi Arabia's northern border, the Seebees have built a main east-west supply road known as the MSR and hundreds of miles of feeder routes that are the supply lifelines for a half million-man army.

Their proud product - a surface almost as hard as pavement in some places but suddenly absent in others - creates a traffic flow as individual as the vehicle being driven.

Eighteen-wheelers and other large trucks generally stay in single-file convoys, plodding along at about 30 to 40 mph. Faster four-wheel-drive jeeps zip through their blinding clouds of dust, passing on the road if there's room and spinning through treacherous sand piles to get around them if not.

Adding to the danger is the habit of drivers routinely forging their own paths alongside the road, or choosing the clearest path regardless of whether it happens to be to the right, center or far left.

Most regular users can tell at least one story of a close call, or worse.

Marine Cpl. Clayton Ervin, who drives the standard military 18-wheeler known as an LVS, said his close call came with a Saudi 18-wheeler that headed straight for him, apparently either not seeing him ahead or not caring.

"I came to a complete stop," said Ervin, 26, of Baltimore. "He never got out of my lane. I got over to the side, but he just kept coming, and he slapped my (side) mirror as he went by. He didn't even slow down."