It said 348,727 attempts nationally were made between Dec. 1, 2015, and Dec. 1, 2016, to start a car by DUI offenders who had been drinking.
In the past 10 years nationally, the devices stopped 2.4 million attempts.
"We now know just how many times people who have already been driving drunk at least once would be out on the road again if not for these lifesaving devices," said MADD National President Colleen Sheeney-Church.
Utah is one of 28 states that require using the devices for all who are convicted of driving under the influence. MADD is pushing for the other 22 states to adopt similar laws.
"Ignition interlocks stopped 955 drunk driving attempts every day" last year, Sheeney-Church said.
"Every state should have laws that require ignition interlocks after the first offense and for at least six months. This gives offenders a second chance, allowing them to continue their daily lives as long as they don't try to drive drunk again," she said.
"There is absolutely no reason to trust that a drunk driver will simply obey an order to not drive or to only drive to work or school as ordered by a restricted license," Sheeney-Church said.
Of note, the Utah Legislature just passed a bill to make Utah the first state in the nation to lower the blood-alcohol content to be considered drunk from 0.08 to 0.05. Gov. Gary Herbert is considering whether to sign or veto it.