The crash happened just before 10:15 p.m. when the Honda Civic jumped the curb in front of the Capital Theater at 204 Massachusetts Ave., Arlington police said.
Three teen boys who saw the crash stopped to help police get the unconscious man out of the car so police could provide life-saving measures until paramedics could arrive.
Responders rushed the man to an area hospital for treatment.
A preliminary investigation found the man had likely suffered distress before the crash, police said.
Officers didn't release any information on the driver or updates on his condition.
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