Montgomery County residents are slightly less satisfied with living in the county than they were two years ago, and they point to traffic congestion as the reason, according to a recent survey of residents.

Despite those complaints about traffic and concerns over growth, 92 percent of the 646 residents responding to a random telephone survey rated Montgomery County as an excellent or good place to live.

In the 1985 survey, 51.8 percent rated the county as an excellent place to live and 43.4 percent rated it as a good place.

In the most recent survey, 42 percent gave the county an excellent rating and 50 percent gave it a good rating.

The survey, conducted between June 17 and July 10, was done for the county by The Survey Research Center and Institute for Government Service of the University of Maryland.

The county office of Management and Budget, which paid less than $10,000 for the survey, will use its results in drawing up budget priorities and trying to assess how residents feel about the county's direction and goals.

Complaints about traffic also showed up when respondents were asked to assess problems in their neighborhoods. Traffic was cited as the number one complaint by 21.8 percent of the residents. The next higher number of people registered no complaints, and the third highest category was concern about overdevelopment. According to the survey, residents travel an average distance of 12 miles to work and spend an average of a half-hour commuting each way.

Overall, however, residents were satisfied with their homes, giving an average grade (on a scale of 1 to 10) of 8 to their neighborhoods.

Asked why they moved to Montgomery County, 19 percent cited the attractive environment and 17 percent said it was the closeness to work. Following those reasons were public schools, better housing, change in employment, the reputation of Montgomery County, and closeness to public transportation.

In 1985, job opportunities, marriage and family, schools and quality education, and quality of life were top ranked as reasons.

More residents said they feel very safe in their neighborhoods than two years ago (62 percent in 1987 compared with 55.6 percent), and fewer residents called for police, fire or emergency medical services during 1986 and 1987 than in 1984 and 1985 (37 percent compared with 44.4 percent). In 1985, crime was listed as a concern by 3.2 percent of the respondents, but it was not cited by any residents in the most recent survey.

Changes since the 1985 survey include more residents working in Montgomery in 1987 (60 percent compared with 50.8 percent in 1985), and more people using public transportation to commute more than five times a week (6 percent, up from 3.5 percent in 1985). Public transportation gained higher marks (26 percent rated it excellent, compared with 20 percent in 1985). Although fewer respondents thought roads were improving (25 percent compared with 31.4 percent in 1985), fewer thought that roads were worsening (44 percent in 1987, 49.2 percent in 1985).