When Bernard D. Crooke left his post as second in command in the District's Metropolitan Police Department three years ago to become chief of police in Montgomery County, he expected the concerns of residents in the nation's second wealthiest county to differ from those of the congested inner city.

He was wrong.

"Everybody's worried about the same thing: traffic problems," Crooke said in a recent interview. "Traffic problems create a great deal of unrest because they have a direct impact on everyone's comfort.

"Next, people in both jurisdictions seem to be concerned about violent crimes. And in Montgomery County, the biggest concern is burglaries," he said.

Violent crime in Montgomery County, which increased substantially between 1976 and 1980, dropped in 1981. The county, which has the area's lowest violent crime rate, last year averaged only one armed robbery per day, Crooke said. The District of Columbia, by comparison, had an average of about 18 armed robberies a day in 1981, according to a D.C. police spokesman.

Occasionally, the slow pace and the relative calm of police work in Montgomery is shattered by a major dramatic event that makes county officers "feel reborn," Crooke said.

Such an event was the 7 1/2-hour siege last month of the IBM office building in Bethesda by a man wielding several high-powered weapons. Edward Thomas Mann has been charged with killing three persons and wounding six others during the takeover.

"Police work from the patrolman right up to the chief is basically a routine job," said Crooke, 49. "When we do have a big issue, it becomes a team effort. Everyone is pulling together for the same thing.

"Of course the police have other roles such as peace-keeping, traffic safety, and so forth, but when a major crime is breaking you have the feeling that 'This is what we're trained for,' " Crooke said. "I like those distractions. When they happen, I want to be a part.

"I really don't want to see it, but sometimes I say that what we really need in this county is about one good riot a month," Crooke joked.

But on those days when Crooke is going through the simple routine of his job, he said, the morale of the officers in his department is a constant concern.

One issue that soured the relationship between the chief and his rank-and-file officers was Crooke's decision last year to go from an experimental four-day work week back to the traditional five-day work schedule.

Crooke said the move provides the department "more flexibility" in the use of manpower. But many of his officers said the switch disrupted their family lives. They claim they frequently do not have enough time for rest between shifts, and that the department could have exercised the same degree of flexibility with the four-day week.

A group of approximately 100 angry officers met last week and stopped just short of taking a vote of "no confidence" in Crooke, who they say did not do enough to support an officer convicted of battery in Montgomery County District Court. The case stemmed from an April incident in which the officer allegedly struck a handcuffed shoplifting suspect with a piece of an automobile tailpipe.

Another concern for Crooke is race relations in the county. Montgomery, with a white majority, lags behind other Washington jurisdictions in some aspects of race relations, Crooke said. The county has seen an increase in what Crooke termed "hate incidents," including cross burnings, the distribution of racist literature, and anti-Semitic graffiti.

The county, which is now experiencing a steady increase in its minority population, has moved swiftly to head off race-related problems, Crooke said. Officials have established a definite procedure for reporting these hate incidents, a procedure that has now been adopted statewide, according to Crooke.

Also, Crooke said, the police department--which hired its first black officer in 1968--this year will spend more than $40,000 to recruit more minorities onto the force.

Currently, about 8 percent of Montgomery County's 734 police officers are black and only four of the officers are Hispanos, according to Crooke.

Although he said he loves police work, which was also his father's profession, he said the job comes with "unique stresses."

"A police officer lives in constant anticipation that he will have to take a life," Crooke said. "And when a police officer dies, it usually comes from someone who wants to take his life."