The Golden State's plan to issue drivers' licenses to undocumented immigrants has hit a roadblock.

In May 2014, federal officials said that the proposed licenses were illegal, because the documents too closely resembled regular drivers' licenses. California had wanted the two items to be similar, to reduce immigrant fears that they would be unfairly targeted. But the Department of Homeland Security rejected the proposed design, which had a "DP" for "Driving Privilege" on the front and a disclaimer on the back.

Under current law, any such license must be easily distinguishable from all other forms of identification, mainly for security purposes when boarding an aircraft.

There are well over 25 million drivers in California, and as many as five million may be unlicensed. Many of these persons are undocumented immigrants and have never held a U.S. license, while many others have a license that has been revoked or suspended, or has expired. There are a number of applicable laws: