The U.S. National Highway Traffic Safety Administration said Friday it was seeking public comment on General Motors’ 15-month-old petition seeking approval to deploy a limited number of vehicles on U.S. roads without steering wheels or other human controls.

The Specialty Equipment Market Association (SEMA) informed the National Highway Traffic Safety Administration (NHTSA) that it is prepared to challenge the agency in court if it fails to take immediate action to implement the low volume replica car law.