Tribune photo illustration

Tribune photo illustration (Nancy Stone / Chicago Tribune)

A Naperville man was killed in a single-car crash on Interstate 55 Wednesday, according to authorities.

Vernon H. Joy Jr., 71, was traveling south on I-55 near Interstate 355 at about 2:28 p.m. when he lost control of the vehicle, drove into a grassy ditch and hit a light pole, according to Illinois State Police Trooper Aldo Schumann.

A medical condition may have caused the crash, he said. No one else was in the vehicle at the time.

-Melissa Jenco, Tribune reporter