All drivers in Montana must adhere to federal and state laws and regulations when it comes to driving while under the influence of alcohol or drugs. According to FindLaw, for drivers operating a personal motor vehicle with a noncommercial license, the standard blood alcohol concentration level is greater than or equal to 0.08%. Even drivers who do not show visible signs of alcohol intoxication can be subject to a field sobriety test to determine BAC. 

Commercial drivers, however, are subject to even higher requirements set by the Federal Motor Carrier Safety Administration. The FMCSA is the leading regulation and safety agency of the federal government, responsible for the oversight of safe commercial motor vehicle operations nationwide. 

A commercial driver is more than just a long-haul trucker. Any person who operates a motor vehicle for the government, for-hire or private motor carriers (such as the Greyhound Bus service) or community organizations (like church or public shuttles) is subject to the regulations and penalties set out by the FMCSA. 

The FMCSA requires commercial drivers in Montana to maintain less than a 0.04% BAC level while operating a commercial motor vehicle, half of what is allowed for noncommercial vehicles. For marijuana, legal blood level concentration limits are the same for all vehicles, including drivers with a registered marijuana card. 

According to Montana’s Official State Website, though BAC levels differ while driving a personal vehicle, penalties for commercial drivers convicted of driving while intoxicated remain on the driving record for life. Even a personal conviction will affect the commercial driver’s license, due to suspension of driving privileges and other penalties, impacting the livelihood of the commercial driver.