The Thika Super Highway was closed on Thursday evening following riots at the Safari Park Hotel Area.
Reports indicated that angry residents barricaded the road after a PSV vehicle knocked down a pedestrian.
In a video seen on twitter, the rioters used bricks to block the road near the footbridge.
Drivers headed to Thika from Nairobi were forced to turn back as a result of the chaos.
The rioters blocked both the highway and the service lane although traffic headed towards Nairobi appeared to be flowing.