District Police Chief Charles H. Ramsey said yesterday he is worried that recent controversy over the city's drunken driving law might cause police to avoid arresting dangerously impaired drivers.

Ramsey said his officers, fearing "public ridicule," might think twice about arresting an unsafe driver whose blood alcohol level is below .08, the legal standard for intoxication. But if they don't make such arrests, the officers could face criticism for allowing the impaired driver to continue on and cause an accident, he said.

"I want clarity," Ramsey said at a D.C. Council committee hearing. "I'm the police chief, and I sat through the hearing and I'm confused."

D.C. law allows police to arrest drivers with blood alcohol levels between .01 and .08. After recent news reports highlighted cases of police arresting motorists who had a glass of wine with dinner, the council last week passed temporary legislation under which drivers with a level below .05 would be presumed to be not intoxicated. The council's public works committee is considering making that change permanent.

Ramsey defended the law yesterday. Both he and D.C. Attorney General Robert J. Spagnoletti told the committee that the council has focused too narrowly on alcohol and has overlooked the fact that other substances, which do not show up on a breathalyzer test, can impair someone's driving.

Spagnoletti said many drivers who are arrested for driving under the influence but show a low blood alcohol level are given blood or urine tests to determine whether other substances are present. In 2003, he said, about 20 percent of all drivers arrested for driving under the influence underwent such testing, and 94 percent of those tests indicated the presence of drugs, alcohol or a combination of the two. Out of that group, 47 percent tested positive for PCP, 40 percent for marijuana and 14 percent for cocaine, he said.

Committee Chairman Carol Schwartz (R-At Large) acknowledged that blood alcohol content is only one factor in judging impairment. But she said authorities have confused the public by announcing a legal limit of .08 for blood alcohol while police are enforcing a much stricter standard.

"If you want to fight for a lower level, let's do it directly and upfront," Schwartz told Ramsey and Spagnoletti. "Let's not take an .08 law and try to change that without changing the numbers."

Schwartz also noted that her emergency bill -- as well as the permanent legislation now being drafted -- would bring the District into line with laws in Maryland, Virginia and other states.

In addition to establishing the presumption that drivers registering under .05 are not intoxicated, the emergency bill says drivers registering .05 to .079 would be in a neutral zone, with no legal presumption.

Mayor Anthony A. Williams (D) is considering whether to sign the bill. Schwartz said yesterday there are enough votes to override a veto.

Spagnoletti said his department does not break down arrests by drivers' blood alcohol content. But he said a sample of one week's worth of cases referred to his office showed that only 9 percent of them involved drivers with levels under .08 -- and the vast majority of those cases were at levels between .05 and .08.

A 165-pound man would reach a level of .05 after about two drinks, and a 110-pound woman after one drink, although levels vary with food intake, metabolism and other factors.

The attorney general said in his testimony that it was unclear whether the changes passed by the council would force an officer to exercise less discretion in making drunken driving arrests. But he said the changes would affect what happens in the courtroom, which in turn would affect what officers do.

Police in several other Washington area jurisdictions said yesterday that their laws have not prevented them from arresting obviously impaired drivers whose blood alcohol is below .08.

"If you have established probable cause based on driving behavior, personal observation, odor or whatever, all of that is information used before a judge to show evidence that this person was impaired," said 1st Sgt. Kim Chinn of the Prince William County police.

"We make arrests on facts, not on numbers," said Montgomery County police Capt. Tom Didone. "If a person is obviously impaired at .03, they can still be convicted for driving under the influence. But they go into court with the presumption on their side."

Charles H. Ramsey says the D.C. Council has focused too narrowly on alcohol in its DUI measure.