Data released recently on traffic stops made by Montgomery County police show that police continue to pull over African American drivers at a higher rate than their proportion of the county's population or registered drivers.

As they have in past years, police said that comparing traffic-stop rates with the county's population is unfair and probably inaccurate because Census data show only who lives in the county -- not who is driving through. The same is true with the number of registered drivers. Although 14 percent of Montgomery County drivers are black, that does not mean that 14 percent of the people who drive through Montgomery are black.

The question raised for many is: To what should the traffic-stop data be compared, if not the proportion of county residents or registered drivers?

The answer, most seem to agree, is to compare the traffic stop ratios with the "driving population" -- the people who travel on Montgomery County roads.

But those numbers can be hard to get. The Maryland Motor Vehicle Administration tracks the race of registered drivers, but that offers no clue as to where those drivers travel.

To figure out the racial makeup of the county's driving population, police have hired a consultant to conduct a study of Montgomery County roads. Capt. Tom Fitzpatrick, who heads the police department's community services division, said the county has hired Lamberth Consulting, a Pennsylvania company that specializes in what it calls "racial profiling assessment."

The company has designed surveys that study intersections across a given jurisdiction, said Chief Executive Officer John Lamberth.

Observers tally the drivers who pass through the intersection at various points of the day over a certain period of time, noting their apparent race or ethnicity, Lamberth said.

Lamberth said the study in Montgomery began last month and will probably be finished by midsummer. He said his company has conducted dozens of similar studies in cities around the country, starting in 1993.

The traffic stop data released by police June 21 were almost identical to those contained in six previous reports.

Twenty-six percent of the 34,291 motorists stopped from Oct. 1 to March 31 were African American. Fifty-two percent were white, and 13 percent were Hispanic.

Among the 13,028 Montgomery County residents who were stopped in the same period, 23 percent were African American. Fifty-six percent where white, and 13 percent Hispanic.

According to 2003 county estimates, Montgomery's population is 14 percent black, 60 percent white and 11 percent Hispanic. State data show that 14.3 percent of registered drivers in the county are black, and 66.3 percent are white. Figures for Hispanics were not available.

Since 2000, Montgomery County has been required under an agreement with the U.S. Department of Justice to tabulate the race of every driver stopped. The agreement stemmed from a four-year investigation prompted by complaints from the NAACP; the probe concluded that the county was not violating drivers' civil rights. But Justice Department officials said county police issued 21 percent of traffic tickets to black drivers in 1997-98 -- a time when black residents accounted for 12 percent of the county's population.

Montgomery police Chief J. Thomas Manger said the numbers indicate there is no "systemic racial profiling problem in Montgomery County."

Henry Hailstock, president of the Montgomery chapter of the NAACP, said he is reserving judgment on what the numbers mean until the police provide more detailed data.

"One excuse they make is that there are a lot of non-Montgomery residents that are being stopped, and that is impacting the numbers," Hailstock said. "In that case, then they should be reporting non-county stops so they can affirm what they are saying. If they are going to give out hard data, they need to be specific."

Police say that "low-discretionary stops" -- traffic stops that involve little or no officer discretion, such as speeding violations -- show percentages similar to those of traffic stops involving greater officer discretion.

Police say this indicates that officers are not stopping people based solely or largely on race. When officer discretion is removed from the equation, the percentages of African Americans ticketed or stopped are similar to those in situations where officer discretion is applied.

For example, 26 percent of cars ticketed by red-light cameras were owned by African Americans during the most recent reporting period, police said -- the same percentage of African Americans stopped for all traffic violations combined. Fifty-four percent of cars ticketed by red-light cameras were owned by whites, and 11 percent were owned by Asians -- similar to the proportions in the data for all traffic violations.