The Tucson Police Department is changing some of its policies on immigration enforcement.

The changes, approved tentatively during a council study session Tuesday, come after the American Civil Liberties Union of Arizona filed two claims - precursors to lawsuits - against the TPD alleging improper enforcement of the state immigration law known as SB1070.

The ACLU of Arizona alleges Tucson police overstepped its authority with the premise and length of traffic stops.

“Twin problems, one is local law enforcement frequently pulling people over Latino residents in particular, pulling them over on a pretext, for a cracked tail light, or for a light that’s out on the license plate. Things that white, Caucasian citizens are very rarely stopped for," said James Lyall, attorney for the ACLU of Arizona. "We see Latino members of the Tucson community report being stopped for these minor infractions all of the time.”

The other problem, he said, is traffic stops that last a long time simply because Tucson police are awaiting word from federal authorities on a person's immigration status.

"The Supreme Court said that doing that, prolonging the stop for no other reason than to investigate immigration status would raise constitutional concerns. That’s what we have seen repeatedly throughout the state and that’s what led to these notices of claim,” he said.

Tucson City Councilmember Regina Romero proposed changes to city enforcement policy to dictate that police may not initiate a traffic stop just to determine immigration status; may not transport someone to a federal immigration facility based on suspected immigration status; and may not lengthen a traffic stop to wait on immigration determination.

Those policies go alongside city council decisions to prevent officers from questioning crime victims or witnesses, prevent school resource officers from asking students about immigration status, and prevent TPD officers from contacting federal immigration authorities for something unrelated to immigration status, such as translation services.

Responding to concerns Councilmember Karin Uhlich had about racial profiling, Tucson Police Chief Roberto Villaseñor said the department is not disproportionately stopping Hispanic drivers. The city's population is about 43 percent Hispanic, yet 34 percent of the traffic stops are of Hispanic drivers, he said.

The city is also using a new record keeping system to track traffic stops with a new search and sorting system, Villaseñor said. This is something the ACLU of Arizona sought from South Tucson Police when the two worked together to change that department's immigration enforcement policies earlier this year.