Opening And Closing Vehicle Doors

Mont. Code Ann. § 61-8-368, under Vehicle Operating Requirements.

Mont. Code Ann. § 61-8-368

A person may not open a door of a motor vehicle unless it is reasonably safe to do so without interfering with the movement of other traffic. A person may not leave a door open on a side of a vehicle adjacent to moving traffic for a period of time longer than is necessary to load or unload passengers.