A 63-seater bus headed to Nairobi along Thika road overturned at allsops on the oncoming lane after taking down a section of the guard rail separating the two roads.
A 33-seater mini-bus was crushed on the front, indicating a possible head-on collision before the bus overturned. Two lanes were blocked by the overturned bus.
Traffic officers and officials from the Kenya National Highway Authority (KeNHA) arrived and cordoned the area causing an interruption in traffic flow on both sides of the road.
However, no casualties have been reported so far as rescue mission to pull out passengers from the overturned bus is has started immediately.
Motorists who attempted to evade the pile-up using the service lanes were also held up and those heading into town have been advised to use alternative routes.
Vehicles can exit the super highway at the Allsops interchange, join the Outer Ring road, turn to Kariobangi and head to town.
A second option is to exit the Kenya School of Monetary Studies drive through Mathare estate and join Juja Road to town.