(Tacoma, WA)  --  A seven-year-old boy who was hit by a car while trick-or-treating remains in critical condition at a Tacoma hospital.  The crash happened Monday night at the intersection of North "I" and 9th streets in Tacoma.  Police say the driver, 38-year-old Kasey Gunnarson, is facing a charge of vehicular assault.  Authorities believe Gunnarson was impaired while driving.