EDGERTON, Wis. -- Five people are dead after three separate traffic crashes in Wisconsin over just a few hours.

There were two separate crashes in Rock County Tuesday night. Just after 6 p.m., Rock County sheriff's deputies responded to a single-vehicle crash in which the driver crashed into a parked Caterpillar front-end loader. The driver, Reyna Portugal of Janesville, was pronounced dead at the scene.

Less than two hours later, two Minnesota residents were killed and four others were injured in a head-on two-vehicle crash on I-39/90 in Rock County.

The Wisconsin State Patrol said a Dodge Caravan minivan was going southbound near Newville Road in Edgerton when traffic slowed, and the driver, Kelley Waites, 24, was unable to safely stop. She apparently lost control of the vehicle, crossed the median and went into oncoming traffic, where the van collided with a Ford Taurus driven by 25-year-old Jeffrey Albertini, of Madison.

The crash killed a 6-year-old boy and Ruby Alexander, 54, in the van -- both from Rochester, Minn. Alexander wasn't wearing a seat belt at the time of the crash. The name of the boy hasn't yet been released.

Waites and two other teens in the van -- all from Rochester -- were taken to area hospitals with non-life-threatening injuries. The names of the teens are being withheld pending notification of family, according to officials.

Albertini also suffered non-life-threatening injuries.

The crash backed up traffic for hours. It was detoured to Highway 14 in Janesville.

Later, just after midnight Wednesday in Walworth County, neighborhood residents in Lyons woke to the sound of a car crash.

Deputies found the car crashed into a tree with two people dead inside. They were identified as Steven Schedler, 23, of East Troy and Jennifer Weber, 29, of Lyons.

All three crashes are under investigation.