CHICAGO—Two people were killed and two more were seriously injured early Friday when their vehicle hit a concrete wall along a Chicago expressway and plunged off the highway onto a street 50 feet below, police said. The vehicle was traveling northbound on Interstate 55—also known as the Stevenson Expressway—at around 4 a.m. when it struck a concrete wall and tumbled off the edge, striking a light pole before landing on the street in the McKinley Park neighborhood on Chicago’s Southwest Side, Illinois State Police Trooper Omoayena Williams said. Two people in the car were killed and the two others were hospitalized with serious but non-life-threatening injuries, police said. Authorities have not released the names of the victims. The Chicago crash comes days after a pickup truck plunged about 70 feet off a slippery interchange exit ramp in Wisconsin. The driver survived that crash and has said he feels thankful to …