With airlines, rail systems and trucking already deregulated, the government is about to add intercity bus service to its list. By a 15-to-1 vote last week, the Senate Commerce Committee approved legislation that would end more than 50 years of regulation over these bus lines. Enactment of this change is sure to produce objections in those parts of the country where bus routes may be more popular than profitable. But if the legislation works as intended, opportunities for new service in these areas may well be expanded.

The concern about transportation cutoffs is understandable, because many of these same areas were given to believe that when or if train service were cut, they would still have buses. But the federal legislation does contain protections against sudden or drastic elimination of routes. Though some curtailments are likely, the emphasis of the measure is on encouraging more competition, not less, in pricing as well as routes.

The results should not be all that extreme. Ground transportation is even more adaptable to market conditions than air or train travel. Smaller buses, connecting jitney service or other arrangements can be started up profitably and efficiently to replace those services that larger bus lines have been operating unprofitably. In this region, in fact, there already are examples of routes that are better served by smaller bus companies than they were or would be by Metro buses. With the lifting of federal regulatory obstacles to new entrants, more suburb-to-city commuter lines might come into existence.

The deregulation proposals do not mean that bus companies will be allowed to do entirely as they please. There are provisions for preempting state authority on a case-by-case basis if, for example, the Interstate Commerce Commission determined that a state action constituted an unreasonable burden on interstate commerce or too drastic a curtailment of service.

One of the most constructive changes in the legislation is actually regulation, not deregulation: it would bar bus companies from meeting privately and fixing prices--as they now may do under an exemption from antitrust laws. Other provisions would allow firms to adjust prices without strict federal government scrutiny, and would make it easier for new firms to go into business.

The legislation is supported by the industry-- large as well as small bus companies--and by the administration and the ICC. It deserves a chance.