They could be called distant French cousins to the American truck stop. They are the restaurants in the Relais Routiers guide, and their hallmark is inexpensive but fine-quality food.
To find these ever-popular eating places, the traveler should keep an eye out for a rather ubiquitous circular sign that dots French roadsides: Emblazoned in white over a red and blue background are the letters, ''Les Routiers,'' announcing the truck driver's answer to the establishments in the better-known Michelin Guide. Even without seeing the sign, one can spot them easily, for they are the roadside restaurants surrounded by a crowd of cars and trailer-trucks. The ''Routiers'' symbol on a restaurant marks it as one of the elite among French roadside stops because it has succeeded in meeting the triple standard of warm welcome, good food, and value for the money established by the Relais Routiers Guide.
The idea for a truckers' guide was born in the 1930s when a young journalist, Francois de Saulieu, thought that if tourists and travelers could have their restaurant and hotel guide, why not truckers? He set out in 1934 on a trip around France to locate the best places catering to truckers, usually finding them and determining their popularity by the extent of oil spots in the road nearby. He published his findings in a truckers' newspaper, and by the eve of World War II his list had grown to 2,000 entries. The war put an end to it, but after the war the idea was revived. Then, in 1967, two of Francois's sons, Bertrand and Thierry, undertook to publish the list in guidebook format similar to the better known Michelin and Kleber guides. Today it is found beside its older brothers in bookstores all over France.
Since my wife and I first walked into a Relais Routiers, we have been devotees of these welcoming establishments. Though by no means look-alike restaurants, they do have, throughout all of France, a similar layout and ambience. There are usually two brightly lit dining rooms - one, with oilcloth and paper table coverings, preferred by the truckers; and the other, with table linen and cloth napkins, preferred by travelers. One rings with the animated voices and camaraderie of truckers, the other buzzes with the more subdued conversations of families and couples.
Though being a Relais Routiers carries a commitment to offer a full meal at a reasonable price - for 1984 set at a maximum of $5.50, service included - it does not mean that the traveler will miss out on some of the more refined dishes in French cuisine. On a recent trip to the south of France we decided to stop at Varennes-le-Grand near Chalon-sur-Saone, which has two Relais Routiers not more than 100 feet apart. We wanted to see the effect of neighborly competition on the menus. At the Hotel de la Gare, where we ate going down, we selected a bouchee financiere, puff pastry filled with seafood and covered with financiere sauce; colin meuniere, hake fried in butter; and beef tongue with a piquante sauce, accompanied by spinach with garlic croutons, then cheese and dessert. On our return trip we sampled the Relais du Commerce. The quenelle, sauce nantua was superb, as was the veal stuffed with sausage accompanied by a generous serving of fresh green beans. And there was a good selection of cheeses followed by homemade ice cream. Though salad was not included in the menu, we asked for it and it was graciously provided without a supplementary charge.
We found that restauranteurs have tremendous respect for the management of the guide. Monsieur Plat, owner/chef of the Hotel de la Gare, had worked for 12 years as a chef until he could save enough money to buy a restaurant that had a Relais Routiers listing. He said he knew he would not automatically keep the listing because any change of ownership immediately brought an anonymous reinspection to see if the new proprietor was maintaining the same standards. He passed, but if he had not, his Routiers sign would have had to come down.
Subsequent anonymous inspections come about twice a year, and a proprietor has no idea which of his guests might be the inspector. ''There are many restaurateurs who want the privilege of putting up a Routiers sign,'' said Plat, ''but they have not been able to fulfill all three points of warm welcome, good food, and value for money required by the guide.''
Bertrand de Saulieu realizes the dedication it takes to meet these standards, especially the one of offering a full menu at or below each year's set price. Discussing this with him at a lunchtime interview in Paris at (what else?) a Routiers restaurant, I learned that this blend of good quality and low prices was possible only because a Routiers restaurant is an ''artisanal enterprise.'' Typically, it is run by a husband and wife, one in the kitchen and the other supervising the dining room, assisted by their children or a couple of employees. About one restaurant in 10 has a small hotel attached to it of the clean, plain, no-frills variety.
De Saulieu noted that even in a country as slow to change as France the Relais Routiers ''are going to adapt to new conditions; it is inevitable.'' He was referring specifically to the great extention of autoroutes that took place in France in the 1970s and drew truck traffic off the departmental and national highways where the Relais Routiers are located.
At a typical mealtime the Routiers clientele will be two-thirds truckers and one-third tourists, but those ratios are bound to change. ''It is tourism that will save the Relais Routiers,'' he said, ''and our guide is designed for the tourist.'' For this reason, a number of Relais Routiers have sprung up in the heart of towns and cities and even in Paris - clearly off the truck routes.
Because the Relais Routiers concept came into being to serve the truckers, though, de Salieau has gotten 26 of the chain restaurants on the autoroutes to offer a meal at the set price of $5.50, one-half the normal price. This is available to the traveler as well if he produces a current copy of the guide, which means that one meal just about pays for the purchase of the guide. While the Relais Routiers idea originated in France and two-thirds of the guide's 3, 571 entries are there, establishments in Belgium, Holland, Germany, Italy, Switzerland, Spain, Ireland, and Great Britain (especially), also are included.
Surveillance is so thorough and the ongoing search for new listings so widespread that about 10 percent of the listings are dropped each year and a similar number added. This does not mean a total turnover in 10 years, however, since listings often go back many years. The oldest, the Bon Sejour in Vitry-le-Francois, dates to 1935, just one year after the list was established. Since restaurants display the Routiers sign, the guide is not absolutely necessary. But it is a help because some of the banished restaurants are very slow to unbolt their signs - sometimes doing so only after being taken to court. The guide is available in the United States at a bookstore called the Librairie de France, 610 Fifth Avenue, New York, N.Y. 10020.