The penalties for driving sloppy drunk in Minnesota get substantially tougher in August, a change that could affect thousands of drivers each year.

The Legislature this year lowered the threshold for a gross misdemeanor drunken driving offense to a blood-alcohol concentration (BAC) of .16 percent. That's still twice the legal limit for misdemeanor DWIs, but it's .04 percentage point lower than the previous trigger for seriously impaired driving violations.

Dropping the gross misdemeanor threshold by .04 percentage point may not seem like much. But a Star Tribune analysis found that it could result in nearly 3,000 more gross misdemeanor DWIs a year if the average numbers for the past few years hold — a 71 percent increase.

The change will expose those defendants to maximum one-year jail terms, up from 90 days under the misdemeanor standard. It would triple the current $1,000 maximum fine. And it would authorize stiffer bail, result in much higher auto insurance rates and more painful legal bills. Gross misdemeanor convictions also can mean stiffer penalties for subsequent DWIs.

One out of every seven licensed Minnesota drivers has at least one DWI. David Bernstein, chair of the Minnesota DWI Task Force, said the lower threshold will primarily affect repeat offenders, because they have an average BAC of .165.

Some lawyers who represent those charged with drunken driving say the lower threshold is too punitive. But supporters say the tougher law is worth it, because it will save lives.

Research shows that the likelihood of getting involved in an accident spikes above a BAC of .15, said Sen. Ron Latz, DFL-St. Louis Park, the chief sponsor of the legislation in the Senate. He said the threshold of .16 was used in the bill because it's "twice the legal limit" for a misdemeanor DWI, which makes it easier to grasp.

"Hopefully, you'll have fewer people take the serious chance of those extra few drinks," Latz said.

The law got through the Legislature without a fiscal impact analysis, though it seems likely to drive up district court costs for counties.

In the past three years, an average of 5,024 people a year were charged in Minnesota for driving with blood-alcohol levels between .16 and .19. Nearly 6 of 10 were first-offenders, according to the Department of Public Safety. Minnesota has the highest DWI recidivism rate in the nation, at over 40 percent.

From 2011 through 2013, 77 people died in Minnesota and 42 others were injured in crashes involving drivers with BAC levels between .16 and .19. An average of 99 people died each year in all alcohol-related accidents in Minnesota in those years, and an average of 2,440 were injured.

Alcohol-related traffic crashes in Minnesota cost an estimated $204 million in medical expenses, property damage and lost productivity in 2013.

The legislation also synchronizes criminal law with administrative penalties, in that they both will now escalate at the lower blood-alcohol standard.

Some defense attorneys say that while the goals of the legislation are laudable, it will come as a shock to many offenders who may make a single, stupid mistake.

"I think this net is cast so broad you're going to get a lot of people," said Joe Tamburino, a Minneapolis lawyer. He said he has clients with otherwise clean records who would have tripped the new gross misdemeanor standard after drinking at a wedding or holiday party. It doesn't seem right to automatically expose them to such severe sanctions, he said.

"A full year of a revocation of license! The only way you're going to get it back is do the ignition interlock system," Tamburino said, citing a costly monitoring program that requires drivers to give rolling breath tests to keep their vehicles from shutting down.

In addition, drivers charged with gross misdemeanor DWIs must post a bail of up to $12,000 to be released from jail, he said.

Murad Mohammad, another Minneapolis lawyer who defends DWI cases, said that the bill got pushed through as a housekeeping measure without any staff analysis. He noted that the average blood-alcohol concentration for a first-time offender in 2013 was .148. "That puts people awfully close to the [new] limit," he said.

Mohammad said some people may be unable to drive safely at lower levels, while others can function reasonably well even with higher amounts of alcohol in their systems.

The new threshold was supported by the Department of Public Safety, the nonprofit Minnesotans for Safe Driving, and the Minnesota DWI Task Force, a volunteer organization made up of prosecutors, defense attorneys, judges, law enforcers, and members of interest groups that focus on drunken driving issues.

Nancy Johnson, a volunteer lobbyist with Minnesotans for Safe Driving, agreed that some drivers can "get from here to there" with higher blood-alcohol levels, but that falls apart when something unexpected occurs, like a child dashing into the street. She called the lower threshold an important piece of legislation to make the roads safer.

Dan Browning • 612-673-4493