In an effort to reduce highway truck accidents, safety experts are pushing the government to require the installation of "black boxes" -- like those used on jetliners -- to monitor speeds and the lengths of time trucks are driven.

Legislation requiring the Transportation Department to investigate the merits of black boxes as well as new developments in brakes is under consideration by the Senate Commerce, Science and Transportation Committee. The Transportation Department also has taken a tentative step toward exploring the issue -- after rejecting the idea earlier this year.

"Black boxes are our highest priority," said Brian O'Neill, president of the Insurance Institute for Highway Safety. "We would like to get as many on-board recording devices on as many trucks as soon as possible."

The National Transportation Safety Board has long urged that black boxes be installed on trucks as a means of monitoring driver fatigue.

An NTSB study of 200 truck accidents in 1984 and 1985 found that 28 percent were caused by driver fatigue. In a separate study conducted in 1985, the American Automobile Association found that fatigue causes 41 percent of heavy truck accidents and estimated that one in three interstate truck drivers exceeds the government's work rules.

Federal regulations prohibit truck drivers from driving more than 10 hours a day or more than 70 hours in an eight-day period. Log books kept by drivers are so widely abused that they are known in the industry as "comic books." An on-board recording device, known as a techograph, would prevent false record-keeping by recording the mileage and speed the truck is driven.

The legislation also requires the government to explore requirements that new brakes, known as antilock or antiskid brakes, be installed on trucks. Antilock brakes are widely used in Europe. Brake performance is believed to be a contributing factor in a third of heavy truck accidents.

Sponsored by Sens. John C. Danforth (R-Mo.) and Brock Adams (D-Wash.), the legislation would also close a loophole in the law that allows big trucks, buses and their drivers to avoid federal safety standards around large metropolitan areas such as Washington, Chicago or Kansas City. The loophole, known as the "commercial zone exemption," has been blamed in the truck accident last year in Riverdale, Md., that killed two 17-year-old high school girls when a dump truck with faulty brakes rolled into a small car.

Federal truck and bus standards dating from the 1950s exempt trucks over 10,000 pounds from federal inspection if they are operating in a "commercial zone" -- usually areas around cities.

Lobbyists for the trucking industry say they support the move to end the "commercial zone exemption." But they oppose parts of the bill calling for black boxes and new brakes. Instead, the American Trucking Association supports a government study of the issue.

"They can be tampered with," said Forest Baker, a former truck driver, now a trucking consultant in Idaho. "They are no better than the support program that uses them. You have to have someone to analyze the data. It has to have enforcement."

Baker said he interviews 25,000 truck drivers annually and finds that about 7 percent of them drive longer hours than federal regulations allow -- but that each year, it is a different 7 percent. Baker blames trucking deregulation, which, he said, forces truck drivers to bend the rules to survive.

"The average driver earns between $17,000 to $19,000, and he has to cheat to do it," Baker said.