The Council Bluffs Police Department reports a semi tractor-trailer rollover accident occurred Wednesday morning. The accident happened on southbound Interstate 29 at mile marker 54, when the rig went out of control due to slippery road conditions at the Ave. G entrance ramp onto the interstate. The truck and trailer went across the embankment between the interstate and ramp, landing on its side across the entrance ramp. No injuries were reported. The entrance ramp was closed until the truck and trailer could be removed.