DES MOINES, Iowa -- The investigation into what caused a metro party bus to crash this weekend is expected to be completed on Tuesday.
Investigators with the Iowa Department of Transportation first cited mechanical issues as the problem, but further detailed on Monday it believes the bus lost its steering abilities, which then caused it to lose control and roll into a ditch.
On Saturday, a group of 21 people were headed from Des Moines to Adel when the bus over turned while heading westbound on Interstate 80 by Grand Prairie Parkway near Waukee.
The DOT says the bus, owned by Elite Party Bus based out of Altoona, passed its required annual inspection but there were visible maintenance issues when looking at the vehicle. A passenger on the bus tells Channel 13 the converted school bus did not seem safe for interstate travel because it was old and rusty.
Passenger Blaine Bierschenk says the bus was traveling about 60 miles per hour when it hit a large bump in the road, causing it lose control and overturn. After the bus overturned, Bierschenk helped passengers get off the vehicle and asked the driver what happened. Bierschenk says the driver admitted to "somehow" losing control of the steering.
According to Bierschenk, the five people injured in the accident were taken to the hospital to be treated for mild concussions, bumps, and bruises. He says the passengers were refunded their money, treated to dinner by the bus company, and the company's owner offered to pay for medical expenses.
The owner of the company declined to comment on the accident.