If a truck driver is convicted of speeding while behind the wheel of a Toyota on Saturday night, should that disqualify him from getting behind the wheel of 18-wheel tractor-trailer rig to haul freight Monday morning? The Transportation Department's Federal Highway Administration, in a move to toughen the safety regulations that apply to the country's 3 million commercial drivers, is seeking answers to this and 13 other safety questions. The key question: should off-duty driving habits be considered when deciding if someone can haul freight for a living?

Last week's Federal Register notice came in response to a National Transportation Safety Board recommendation for tougher standards. Government studies show a 34 percent increase in the number of people killed in heavy-duty truck accidents between 1976 and 1979. An NTSB analysis found "the driving backgrounds of many of the commercial drivers involved in accidents during 1978 [in which 6,350 people died] included records of traffic convictions, driver license suspensions and accidents, indicating a flagrant . . . disregard for the safety of other highway users."

The last time the government tried to toughen the standards, a federal judge found there was insufficient evidence to show a correlation between off-duty driving habits and on-duty performance. FWHA hopes the new studies fix that problem. But Teamsters union safety expert Warren Rheaume is skeptical that the correlation is strong enough to warrant taking away a trucker's livelihood for off-duty traffic offenses.