The politics of where and when the New York Police Department enforces traffic laws is coming under scrutiny as Mayor Bloomberg pushes a congestion-pricing proposal to ease traffic in Midtown Manhattan.

Enforcement of city parking and traffic laws for years has been irregular: residents in the East Village complain of overzealous meter maids, while unticketed town cars idle double- and triple-parked in front of Midtown hotels and cause miles-long back-ups.

Some elected officials and taxi drivers are blaming the city’s congestion problem on the police department, saying it selectively tickets drivers who block intersections and double-parked cars to build a case for congestion pricing.

“I have a feeling — not to accuse anyone of doing something cynical — but they haven’t been doing all they can to enforce existing laws because they need to continue the rationale for the plan they have out there,” Rep. Anthony Weiner, a Democrat of Brooklyn and Queens, said at an October 25 hearing on congestion pricing. Mr. Weiner, a declared mayoral candidate and the highest-ranking elected official to speak out against the city plan to charge drivers to enter or leave parts of Manhattan, was referring in his testimony to ticketing vehicles that “block the box.”

Council Member David Weprin of Queens said there is “really no enforcement of traffic laws.”

“Rather than imposing a regressive tax that hurts the middle class, we should be enforcing existing laws,” Mr. Weprin said.

Proponents of the road tax said Mr. Weiner’s testimony was not supported with facts. “Parking enforcement is lacking, but it’s been lacking for years,” the executive director of Transportation Alternatives, Paul Steely White, said. “To suggest there’s a conspiracy theory is ludicrous.”

The number of citywide parking violations issued by the police department has dropped by 6% in 2007 compared with last year.

The largest number of parking tickets in Manhattan was distributed between 29th and 45th streets, east of Lexington Avenue. The number of parking tickets distributed in that neighborhood, however, is down 41% since 2001. On the Lower East Side, parking tickets were down by 15.7% versus last year, while parking tickets distributed in the East Village were up by 8.4%.

Many cab drivers interviewed this week said they were routinely targeted by the police for traffic violations, but private cars were not pulled over for the same offenses. “You see a lot of black cars standing where it says No Parking, but if we go, we get a ticket,” a taxi driver of 14 years, Syed Shah, said.

A spokesman for the police department did not return calls yesterday to explain how the department decides where to dispatch agents. Parking experts said enforcement is often a response to the needs of a particular street, or where the Department of Transportation has alerted police officials of pedestrian injuries or disruptive construction work.

The police department currently has 760 police officers and supervisors in its traffic control division, and about 26,000 enforcement agents patrolling the streets.

Mr. Bloomberg last May announced that the city would be adding 117 new enforcement agents to patrol the streets.

“Any suggestion that we’re not enforcing traffic laws and regulations is absurd,” a spokesman for Mr. Bloomberg, John Gallagher, said in an e-mail message yesterday. “Congestion is and has been a huge problem in this city, and to suggest that it’s artificially manufactured just isn’t dealing with reality.”