HOLYOKE, Mass. (WWLP) – Traffic on Interstate 91 was backed up in both directions on Saturday afternoon following a deadly crash on the median.

According to Massachusetts State Police, the accident was caused by a wrong-way driver. The driver of that vehicle was a 69-year-old woman from Holyoke, who was killed in the crash.

The woman was driving southbound on Interstate 91 northbound in Holyoke in a 2005 Mercedes-Benz. The vehicle struck a 2013 Honda Civic head-on in the left lane.

The driver of the Honda Civic was a 25-year-old Springfield man, who was taken to Baystate Medical Center with serious injuries.

Massachusetts State Police, The State Police Collision Analysis and Reconstruction Section, and the State Police Crime Scene Services Section are investigating why the woman was driving the wrong way.