The Montana Department of Transportation’s State Traffic Highway Safety Section recently compiled information that could be an eye-opener for those who drink and drive.

The information is intended to provide the true cost of driving under the influence. According to state law, it is illegal to operate a motor vehicle with a blood or breath alcohol concentration of 0.08 percent or higher.

No proof of impairment is required for a DUI. The threshold for a commercial driver is 0.04 percent, and the threshold for someone under 21 years of age is 0.02 percent.

DUI laws apply to marijuana, too. A law that went into effect in 2013 establishes a threshold of 5 micrograms per milliliter of THC, the psychoactive chemical in marijuana. And, just like with alcohol, there’s no need to prove a driver is impaired.

Here are some of the impacts a person might expect:

• A serious DUI conviction can remain on a person’s record for life and could drive up insurance rates. In some cases, insurance companies will cancel a policy.

• DUI convictions can stack up. A fourth conviction is a felony and can lead to prison time.

• Drivers with a DUI conviction might find some types of employment unavailable to them, especially jobs requiring commercial driver’s licenses.

• A first-time DUI conviction could mean a suspended driver’s license for six months. Subsequent DUI convictions could mean a license suspended for a year or more.

• A first-time DUI offender could be looking at $5,000 to $6,000 in costs. That could mean a fine up to $1,000, court costs of $500 with a trial, $70 per hour for a public defender or up to $300 per hour for a private attorney, $325 or more for chemical dependency assessment and classes, $200 to reinstate a driver’s license, hundreds of dollars in towing and impoundment fees, up to $120 to install and $70 per month for an ignition interlock, $12 a day or $360 per month for a transdermal alcohol monitoring device like a SCRAM ankle bracelet, and $4 a day or $120 per month for the state’s 24/7 Sobriety Program.

• A DUI crash could easily cost more than $100,000 if there are injuries.