Dozens of extra police were Friday dispatched to help manage traffic flow on the Narobi-Nakuru Highway.
Other teams were sent to the Mai Mahiu route where motorists were stuck on the road for hours, police said.
This followed traffic chaos experienced on the routes as motorists and other passengers rushed upcountry for Christmas festivities.
The police on the ground said there were tens of vehicles involved in traffic chaos.
Inspector General of Police Douglas Kanja said he had ordered the deployment of reinforcement teams including General Duty Police Officers from all police stations along the Nairobi-Nakuru Highway and dispatched a police chopper from the National Police Service Airwing to assist the Traffic Police Unit clear and ensure free flow of traffic.
“The National Police Service is further appealing to all motorists to adhere to traffic and regulations rules by observing speed limits, driving roadworthy motor vehicles and avoiding overlapping on the roads,” he said.
The teams will work in shifts until the chaos is addressed amid fears they may persist.
Police said drivers’ indiscipline was the main cause of the chaos witnessed.
Motorists and passengers using the Nairobi-Nakuru Highway and the Kamandura-Mai Mahiu Road were caught up in heavy traffic on Friday caused by a trailer accident.
The accident led to the closure of these roads, forcing some travellers to spend the night on the road.
The traffic jam persisted for a long time despite efforts by traffic police to restore normal flow.
The situation has affected many travellers heading home to celebrate the Christmas season.
Police also said trailers blocking the road had been removed.
The Kenya National Highway Authority (KeNHA) said there was significant congestion on the Rironi-Naivasha-Nakuru road and the Rironi-Mai Mahiu-Naivasha section.
The Authority, with the support of traffic police, are at hand to give the necessary guidance and ensure smooth traffic flow so you can reach your destination safely and without delays.
The authority asked motorists to use alternative routes: Naivasha-Njabini-Olkalou-Dundori-Lanet-Nakuru;
Flyover-Njabini-Olkalou-Dundori-Lanet-Nakuru; and Ngong-Suswa-Narok- Mau Narok-Nakuru.
The Nakuru-Nairobi highway is not new to heavy traffic during the festive season as it is the main route for Kenyans travelling to Western, Nyanza and Rift Valley regions.