BOOK REVIEW : Travelogue as High-Speed Odyssey : ROAD FEVER A High-Speed Travelogue <i> by Tim Cahill</i> , Random House $17.95, 288 pages

“We are not men, we are roto, “ announces Tim Cahill at a moment of epiphany somewhere in South America. “We were laughing so hard we might have been in a state of infant ecstasy. We could handle anything the Pan-American Highway could throw at us.”

Roto is a code word for the zonked-out and slightly desperate zaniness that characterized a bid by Canadian “adventure driver” Garry Sowerby to set a world record for the longest and fastest south-to-north drive, 15,000 miles from Tierra del Fuego to Prudhoe Bay. Cahill, who rode shotgun, captures the spirit of roto in “Road Fever,” a supercharged account of the 1987 odyssey.

Cahill, a veteran travel writer and adventure journalist, is honest enough to admit that the effort to set a speed record requires meticulous planning and rigid adherence to schedule. “The essence of our adventure,” he observes, rather sourly, “was to avoid adventure at all costs.”

So Cahill cheerfully plumps up his book with plenty of intriguing digressions on everything from the economics of free-lance travel writing to the politics of the “Guinness Book of World Records.” He tells us what it’s like to chew coca leaves, how the Sandinista government sought to attract “classical” as opposed to “sociocultural” tourism, why he detests “Northworst” Airline. Indeed, some of Cahill’s best tales of adventure and survival are flashbacks to other treks at other times and places.

The trip that Cahill and Sowerby actually took is truncated and rather curiously paced. Cahill literally backs up the narrative and takes a running start on his account of the drive itself, so that it’s not until Page 127 that Sowerby and Cahill actually set out on their speed run: “Let’s see what this baby’ll do,” Sowerby comments dryly. By Page 263, they’ve reached Dallas--and Cahill takes only 14 more pages to describe the entire North American stretch of their drive, as if nothing much happened once they crossed the Rio Grande.

The adventures in South America consist mostly of breathtaking sunrises and sunsets, harrowing bureaucratic obstacle courses (“Document hell,” as Cahill puts it), “bus-plunges” and other vehicular disasters and fearful encounters at miscellaneous police checkpoints. Sowerby and Cahill never actually run into bandits, drug-runners or guerrillas, although they have stocked their truck with crash-bars, bulletproof vests and jungle knives as precautions against an ambush.

You get to know someone pretty well after spending 24 days in the cramped quarters of a Sierra pickup truck, and what we learn about Cahill is that he is capable of snide humor, ill temper and a general moodiness posing as a kind of on-the-road Weltschmerz. He complains, he broods, he contemplates violence against Sowerby over an imagined slight to his driving skills.

“I decided, in what seemed an enormous emotional sacrifice at the time, not to punch the hell out of Garry Sowerby on the spot,” Cahill reveals. “What I would do was wait until we hit Prudhoe Bay. We’d be standing in the snow at the edge of Beaufort Sea talking about men and machines, time and the elements, and I’d just haul off and pop him a good one. Bam!”

Cahill is fully capable of the requisite descriptions of natural wonders, but he also calls our attention to the squalor and sickness and pain that he saw along the way. Thus, for example, he pauses to explain why the sight of a certain model of automobile in the streets of Buenos Aires is a terrifying reminder of the worst excesses of the secret police, who favored the car for “disappearances.”

“It was the banality of evil writ large,” Cahill observes, “terror as a black Ford Falcon.”

Even when Cahill glimpses something almost sublime, his sense of satire and his street smarts assert themselves: “We were, I thought, ascending into realms of the spirit,” he writes of the road to Quito. “Ahead, through the purely spiritual fog, I could see a looming, giant form. A revelation, no doubt. It was, of course, a large truck. . . . I could barely make out some markings on this erstwhile celestial apparition: the markings read, COCA-COLA.”

“Road Fever” is a travelogue with an attitude, a road book with a ragged edge and purely gonzo sensibilities. But even if the book itself is more than slightly roto, it’s well worth going along for the ride.

Next: Margarita Nieto reviews “After Egypt: Isadora Duncan and Mary Cassatt, A Dual Biography” by Millicent Dillon (William Abrahams , E.P. Dutton).