A new report suggests that the Mile High City’s police don’t arrest off-duty Denver cops for driving drunk unless they are involved in collisions, and a new department policy will help prevent requests for such professional courtesy from being honored.

Since 2005, when Independent Monitor Richard Rosenthal began monitoring police discipline, Denver police have arrested five of their own who were found to be drunk after a collision, he said in his second-quarter police and sheriff discipline and critical-incident report. But none has been arrested solely for driving under the influence.

At the same time, Denver Police Department data show that for about every three of the city’s residents arrested for DUI, there is one resident arrested for a collision in which they were found to be intoxicated.

Colorado jurisdictions outside Denver aren’t reluctant to arrest Denver cops for drunken driving, the report said. “There has been a 4-to-1 ratio of DUI traffic arrests to DUI arrests ensuing from collisions involving off-duty DPD officers in other jurisdictions.”

Based on the 3-to-1 arrest ratio in the general public, it would make sense that roughly 15 Denver police officers should have been arrested for DUI with no collision, the report said.

“During that same time period, however, 10 DPD officers have been arrested for DUI in other jurisdictions, with only two of those arrests ensuing from a traffic collision,” the report said.

Rosenthal concludes that some of Denver’s approximately 1,400 officers expect to be let off the hook by their fellow cops, the report said. And the study suggests they may be having their way.

In response to the report, to be released today, DPD will take steps including requiring an officer who stops an intoxicated Denver cop to call a supervisor to the scene, Rosenthal said in the report.

Denver police union president Nick Rogers called the report “another attempt by Richard Rosenthal to cast a shadow on the department.”

Noting that more than 75 percent of Denver cops live outside the city, he said the statistical analysis is thin. “There are no facts to back this up,” he said. “I think it’s slanderous.”

Denver police spokesman Sonny Jackson referred calls for comment to Manager of Safety Charles Garcia’s office.

“While there have been no reported cases, we take the monitor’s concern related to the absence of arrests of off-duty DPD officers for DUI very seriously,” Garcia said in an e-mailed statement. “Any such reports of these actions would be thoroughly investigated and appropriate discipline applied.”

The report also called too lenient the 26-day suspension of a Denver police officer for driving under the influence and berating the arresting officer for arresting a fellow cop.

Rosenthal said the case didn’t prompt him to study DUI arrests of off-duty cops.

“I have been keeping an eye on this for a long time,” he said.

On April 28, Garcia suspended an unidentified officer for DUI, unlawful possession of a firearm while intoxicated and rude and offensive behavior toward the arresting officers, “along with blatant attempts to obtain preferential treatment based on his position as a police officer,” according to the report.

The officer had a blood-alcohol content of 0.246 percent, three times the legal limit, and a loaded firearm in the vehicle with him when he ran off a mountain road and down an embankment.

When the officer who responded to the accident told him he was arresting him for DUI, the driver launched a profanity-laced and abusive tirade.

Among the comments:

“I started in the suburbs of Chicago and I worked in Chicago, Chicago PD, and I now I work in Denver. I have never, never, ever f—– another policeman, and I don’t know what you guys do up here.

“You’re an a——.”

The officer received a 16-day suspension without pay for the DUI and a 10-day suspension without pay for unlawful possession of a firearm.

Public safety spokeswoman Kathy Maloney said Garcia reviews the facts of each case thoroughly and independently.

“Following his review of this case, the manager applied 26 days, which is within the parameters of the discipline matrix,” she said in an e-mail.

Rosenthal compared the case with two others, including one decided by former Manager of Safety Ron Perea. In that case the officer was driving 80 mph in a 55-mph zone and had a blood-alcohol content of 0.217 percent. The officer begged not to be arrested based on his law enforcement position.

“He did not, however, insult or demean the arresting officer,” the report said.

Perea suspended him for 30 days for improperly attempting to obtain preferential treatment based on his job, the report said. He also received a 14-day suspension for unlawful possession of a firearm.

Garcia has decided to create a new rule specifically prohibiting solicitation of preferential treatment by a Denver cop, Rosenthal added.

“This issue will likely be more appropriately resolved in future cases due to the Manager’s decision to create” the new rule, the report said.

Tom McGhee: 303-954-1671 or tmcghee@denverpost.com