Officer Charles Schauer, 33, was sitting in the passenger seat of a Dodge SUV as Erin Zilka, 35, was driving him on an Illinois highway around 6 a.m.
A box truck had collided with a pickup truck earlier in a separate incident and they collided, according to Fox 32 Chicago.
Schauer was pronounced dead at the scene and Zilka was hospitalized with non-life threatening injuries and charged with a DUI, the outlet reported.
"The City of Berwyn Police Department is grieving the loss of a well-respected Police Officer, Charles Schauer, a ten-year veteran," the department wrote on Facebook.
Three lanes of the highway were shut down for hours following the incident before reopening around 10:20 a.m, the station said. State police are currently investigating.