Blue lights on police cars. Green lights on command centers. White tail lamps on motorcycles. On occasion, the Legislature is asked to regulate the kinds of lights vehicles may display, including those on the cars and trucks used for emergencies.

The North Dakota Senate on Monday unanimously approved three "light bills," along with separate legislation that allows North Dakota Forest Service cars and trucks to be designated as emergency vehicles. The House already has approved all four measures, and they now go to Gov. John Hoeven's desk.

State law now allows emergency vehicles, including fire engines and police cars, to have flashing red and white lights. Allowing them to display flashing blue lights as well should make them more visible in a snowstorm or thick fog, said Sen. John Andrist, R-Crosby.

A new state law that allows a green flashing light will reserve the light for command centers in emergencies, said Sen. Tracy Potter, D-Bismarck.

"In a serious emergency, vehicles may be driving there with their flashing red lights on, and when they get there, one of those vehicles will turn on a flashing green light," Potter said. "That will become the command center for that emergency."

Nine types of government agencies, including local police departments, the Game and Fish Department, the National Guard and the state Parks and Recreation Department, may operate emergency vehicles. On Monday, the Senate voted to add the state forester to the list.

Andrist said the designation would apply when state Forest Service vehicles were being used to fight wildfires.

Separately, the Senate endorsed requiring all motorcycles to have at least one stop lamp, which lights when the cycle is stopping, and at least one tail lamp. As defined in state law, a tail lamp may be either a red light at the bike's rear, or a white light that illuminates its license plate.

The motorcycle light bill is HB1205. The green light "command center" bill is HB1234. The state forester bill is HB1087. The "blue light" emergency light bill is HB1310.