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The crash happened at 1:35 a.m. on northbound Interstate Highway 680 just north of the state Highway 242 split, Maguire said.
Michelle Brewer allegedly rear-ended a 2001 Honda Accord, causing minor injuries to the four people inside.
The passenger in Brewer's car, a 56-year-old Alameda resident, suffered major injuries and was transported to John Muir Medical Center in Walnut Creek.
Brewer was also taken to John Muir, Maguire said.
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