While the auto was still moving, the man allegedly jumped out and started shooting at the woman.
The shooting at about 4:15 a.m. Wednesday forced authorities to close the Chicago Skyway for about five hours.
Authorities say a 30-year-old man fatally shot a 49-year-old woman on a major Chicago expressway before shooting and killing himself. Then police who were stationed near the gate approached the man, who shot himself. The vehicle eventually crashed into a wall near the toll plaza.
The woman suffered a gunshot wound to the body, and the man suffered a gunshot wound to the head, police said.
Chicago Fire Department crews were called to 8800 south on Eastbound Iterstate 90 about 4:15 a.m. for people shot and found two people dead at the scene, said fire department spokesman Walter Schroeder.
Guglielmi said investigators believe that the two were married but they were continuing to try to verify their identities.
Police spokesman Officer Ron Gaines tells the Chicago Tribune the woman was shot in the back, and both were found unresponsive at the scene. He says the deaths were being investigated as possibly domestic-related.
Police cordoned off the area where the Chrysler had crashed and blocked traffic east of the Dan Ryan Expressway while conducting an investigation.