A group of civil rights attorneys filed a lawsuit Thursday challenging the Los Angeles Police Department's recently approved policy on impounding the cars of unlicensed drivers.

The lawsuit filed in Los Angeles County Superior Court argues the LAPD policy change illegally requires a mandatory 30-day impound of drivers stopped with an expired California driver's license or a foreign driver's license.

It argues the department unlawfully prevents the owners of vehicles from getting their cars back before 30 days when another driver who is not the owner was at fault for the violation and impound.

The lawsuit also contends LAPD procedures for notifying car owners of an impound deny alleged violators due process by not notifying them of a hearing date to contest an impound.

The city Police Commission last week approved a new policy that allowed offenders who have valid identification, car registration and proof of insurance to avoid a 30-day impound.

Police Chief Charlie Beck, who proposed the policy with the backing of immigrants' rights groups and Mayor Antonio Villaraigosa, said last week the change was an attempt to eliminate confusion by officers in the field over two conflicting laws regarding when to impound a vehicle and for how long.

He also said the policy unnecessarily penalized some of the city's poorest residents.