Six Nairobi roads among them Lang’ata road and Uhuru highway will be closed on December 1 for the Grand Nairobi Bike race.
Haile Sellasie Avenue, Bunyala road, Lower Hill road and Aerodrome road will also be affected.
The race will take place between 8.00 am and 12.30 pm on Sunday.
Kenya Urban Roads Authority (KURA) has advised motorists to use alternative routes to avoid inconveniences.
The race is the first professional timed cycling race to be held in Kenya, aimed at creating awareness on tree planting.
According to the organisers, the main race will be 70kms and the black mamba, 35kms.
Motorists are advised to plan ahead to avoid delays.