LOS ANGELES (CBSLA) — Authorities say they’ve arrested 741 people for suspected drunken driving offenses within the first 30 hours of the Memorial Day weekend.

“At least 18 people have been killed in collisions on California’s roadways this holiday weekend,” the CHP said via Twitter. “Tragically, at least half of those who died were not wearing a seat belt.”

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In 2018, 37 people were killed in traffic accidents within CHP jurisdictions during the Memorial Day period. Of those, nearly half were not wearing a safety restraint, authorities said.

On Friday evening, authorities launched a maximum enforcement period which is expected to remain in effect through 11:59 p.m. Monday during which all CHP officers will be on the lookout for drunken drivers.

“I’m surprised to hear that DUI arrests are still commonplace on holiday weekends in light of the fact that we have ride-sharing companies like Uber and Lyft and interlock device laws in place,” said Lou Shapiro, a criminal defense attorney and TV legal analyst.

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For first time offenders, Shapiro said, the standard DUI terms may include three-months of informal probation and completion of a DUI program, as well as the installation of an ignition interlock device.

Those who have blood-alcohol content levels of .15 or above will be subject to a 9-month or longer probationary period, said Shapiro.

In addition, legal fees for first-time offenders range anywhere between $5,000 – $10,000, excluding court fines of $2,300 and an additional cost for the DUI program.

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“There is no excuse for driving impaired,” the CHP said in another tweet. “Stay put, call a cab or ride-share company. Arrange for a sober driver in advance. Stop putting your life and the lives of innocent people at risk.”