Portland police say a 49-year-old man who struck and injured a woman flagman at a road construction site was apparently huffing drugs behind the wheel. But it wasn't your typical drug.

Patrick Miller was taken into custody by police Wednesday afternoon after hitting 47-year-old Margot Davis in Southeast Portland. Davis, who was flagging and directing traffic at the construction zone, was seriously injured.

Miller, said police, was huffing, or inhaling, nitrous oxide just prior to the crash.  Davis was standing on a sidewalk when she was hit, she's expected to survive. Nitrous Oxide is the formal name for laughing gas.

Miller's car continued over the curb and went through a grassy area before finally coming to a stop.  Officials don't know where he got the gas, it's not something that's readily available to the general public.  Miller is facing a variety of charges.