(The road can be dangerous. It can be hot and wet and dusty and rough. There is one thing the road always is. It is always lonely. No one knows this better than the hundreds of men who drive the great convoys of the 1st Logistical Command. Like all support troops, they are not constantly in battle, though they often fight. Through the 15-hour workdays, the months without a day off, loneliness is their only constant companion. This is the story of one day.)

PLEIKU, Vietnam—Sgt. Michael D. Purlee, 21, arose an hour before dawn, shivering slightly in the crisp mountain air.

He dressed, ate quickly and by 6 a.m. was with the Black Angel.

That is the name of Purlee's 2 1/2-ton steel-plated gun truck. Its assignment was to accompany a small 1st Log supply convoy 75 miles north through Kontum to Ben Het, the Special Forces camp near the Cambodian border.

Purlee was mildly apprehensive. The last time he had been to Ben Het, late in June, 24, the camp had been under siege, the convoy had been ambushed, and a man in his truck had been killed. He examined his equipment with special care.

At 8 a.m. the Black Angel joined the convoy's other trucks in the 563rd Transportation Co.'s yard, and Purlee's gunner, Spec. 4 Richard F. Stone Jr., 18, and his driver, Pfc. Glen R. Dye, 20, joined him.

Stone has been in Vietnam seven months and has been ambushed 20 times. He had been driving the Black Angel during the siege of Ben Het.

This morning, as a light rain fell, he went over the truck's guns inch by inch: twin-mounted 50-caliber machine guns, two M60s, two M79 grenade launchers, three M16 rifles and two .45 pistols. The radio didn't work. He replaced it.

At 9:30 a.m., the convoy commander, 1st Lt. James M. Greer, 24, briefed his men.

"Let's get back before dark," he said. "When you get there, unload fast. On the road, keep your interval, keep your eyes open. Let's have a good convoy."

Then there was nothing to do but smoke and talk and wait for word that the road had been cleared of mines.

"It's going to be a great ride," someone joked.

"It isn't so great when you do it every day," said Purlee. "I've been here 13 months, 15 hours a day, 7 days a week. I've got 28 days to go."

At 10:10 word came. The men put on flak jackets and steel pots. Dye started the engine. Stone snapped bandoliers of ammo into the four machine guns. Purlee got on the radio.

Five minutes later the convoy was rolling north into the cool mountain meadows of central Vietnam. The rain had let up a little, but that was a prelude to choking sheets of dust. It is a closed equation on the road. You get one or the other, and sometimes both, which is worse.

By 7:15 p.m. that night they were back in Pleiku. Nothing had happened. Nothing at all.

Purlee took the Black Angel to the motor pool. Gear and weapons were cleaned and stowed. By 9:15 p.m. the workday was over. It had lasted 15 hours.

Purlee thought it had been OK as days go. There had been no ambush. There had been apprehension, preparation, vigilance, strain. But that was all.

He was black with grime. He ate, showered, wrote home and went to bed at 10:30.

Six and a half hours later he would get up again and go to work the way he did every day.

The way he did 364 days a year.

The other day was his day off.