Motorists travelling between Eldoret and Nakuru have been advised to use the Makutano - Eldama Ravine - Kabarak - Nakuru Road to avoid congestion after a tanker overturned and spilt oil on the road.
The Kenya National Highways Authority (KeNHA) said in a statement Monday evening the accident occurred at Nyanja, some 3km north of the Mau Summit interchange.
"This has made the road very slippery and recovery trucks are not able to access the vehicle," KeNHA said.
The authority said the process of clearing the spillage would take longer.
"The Authority is collaborating with other Agencies to wash away the spilt oil, and considerable progress has been made. However, the exercise is taking longer than anticipated."
KeNHA said the tanker was ferrying palm oil.
"The Authority has mobilised all efforts to ensure the road is open and safe to road users within the shortest time," it added.