The number of accidents involving Montgomery County school buses declined in the 1982-83 school year for the second year in a row.

School officials said this week that 171 accidents--94 of them adjudged preventable--occurred during the 1982-83 school year, down 19 percent from last year's 211 when Montgomery registered the largest number of accidents of any school jurisdiction in the state. There were no fatalities in Montgomery last school year; there was one the year before.

A little more than half of the system's 90,000 students ride school buses. Elementary students are eligible to ride if they live more than a mile from school; junior high school students if they live more than 1.5 miles away and senior high school students if they live more 1.75 miles from their school.

Statewide figures for school bus accidents in 1981-82 were not available, but school officials in Rockville cautioned against comparing Montgomery's statistics with other jurisdictions because, with 743 buses covering 500 square miles, Montgomery has one of the largest fleets and logs one of the greatest mileage totals in the state.

Larry Skinner, transportation director for Montgomery officials, said that in keeping with state regulations, Montgomery has implemented a number of procedures designed to reduce the number of accidents. Skinner said each driver must undergo a routine medical examination annually and a more intensive examination testing night vision and steadiness every two years.

Skinner said drivers also participate in an annual retraining program (this year's takes place today) and attend an annual seminar on special education and human relations. Drivers also will be evaluated on their performances in a four-hour safety course that includes bridges and railroad crossings.

Persons with more than three moving-violation points on their licenses cannot work as school bus drivers.

School buses get monthly maintenance checks, plus three safety checks a year, and they must be retired after 12 years of service.

Skinner said when the number of accidents was calculated against the number of miles traveled, last year's performance was even more dramatic than the raw numbers reflect. He said that in the 1979-80 school year there were 25.9 accidents per million miles traveled, including 13.3 per million miles that officials concluded were preventable, while in the 1982-83 school year, when the buses traveled 10.6 million miles, the comparable figures were 16.1 and 8.9.

School officials are required to report accidents to the state education department's transportation branch when there is $100 damage or any personal injury.

In Frederick County, Dale Gangawere, supervisor of school transportation, said school buses were involved in 30 minor accidents last year. No one was injured in those mishaps. Gangawere said Frederick schools operate 180 buses of their own and contract for 70 more.