Los Angeles police officers have been told they face possible discipline if they ask a judge to dismiss traffic charges against motorists when they can't recall the details of the alleged infractions, according to an internal memo sent to officers by top LAPD officials.

Under a new directive, which was made after court officials noticed an apparent rise in the number of such dismissal requests, "officers are required to testify to the best of their ability" and, in instances in which they cannot remember what occurred, must base their testimony on what they wrote on the citations.

The order upends a long-used, unofficial practice of traffic judges granting officers' requests for a case to be dismissed when they have what is referred to in police shorthand as N.I.R. - no independent recollection.

The ban has angered the leaders of the Los Angeles Police Protective League, who represent the LAPD's nearly 10,000 rank-and-file officers and have demanded to meet with department officials to discuss the change. Paul Weber, president of the league, questioned the ban on dismissal requests, saying it created unreasonable expectations, especially for traffic enforcement officers who write dozens of tickets each week.

"Officers shouldn't be put in a position where they are trying to force these [tickets] through," Weber said. "It doesn't matter what they wrote on the ticket. What matters is their ability to articulate what they saw and why the driver broke the law. People have a right to confront their accuser, even in traffic court, and we have to be able to put on a case. If we can't do that because we don't remember, then that person should be let go. That's the way our system is built."

Deputy Police Chief David Doan said it is for a judge to decide whether a case should be dismissed. "We felt we needed to remind our people of their obligations," Doan said in an interview. "If they need to write down some notes to remind themselves later of what happened, then they should be doing that. But to just say 'I'm not going to testify' is not acceptable."

Los Angeles Superior Court officials alerted the LAPD and the city attorney's office this summer after traffic judges and other courtroom staff raised concern over what seemed to be a surge in the number of officers asking for cases to be dismissed. Statistics on the number of cases dismissed because of police recollection issues are not collected and so the size of the alleged increase is unknown, a court representative said.

Police officials did not offer an explanation for what may have led to the increase in dismissal requests.

The issue touches on a perennially sensitive issue in the LAPD and other urban police departments: How supervisors can increase officers' productivity and write more citations - which puts more money in city coffers - without overstepping labor rules that forbid them to implement ticket quotas. Officers frequently grumble about the pressure they feel to write more tickets, while their supervisors, in turn, must answer pointed questions from higher-ups about dips in a station's citation totals.

Through the middle of August, LAPD officers wrote 512,211 traffic citations - a nearly 3% increase over the same period last year, but a 5% decline over 2008 figures, according to LAPD statistics.

One officer, who requested that his name not be used out of concern he would be disciplined for criticizing the ban, said he worried that the new policy places an unspoken pressure on police to testify to details that they might not remember and puts them in a no-win situation. "It's a tightrope. If you're on the stand and you get it wrong then the public suffers. But if you ask the judge to do the right thing and dismiss the case then you face discipline."