Pol Maj Gen Jirasant Kaewsaengek said traffic will return to normal at Pathumwan, Ratchaprasong and Asok areas on Monday morning.
The roads at the three intersections remain closed to allow PDRC demonstrators to dismantle their stages and City Hall workers to clean up the areas.
Pol Maj Gen Jirasant said they will work throughout the night.
The road clearance comes after the PDRC decided to end the three stages and move to Lumpini Park on Sunday.
Traffic in Bangkok will be better on Monday, the officer said, but cautioned about possible traffic problems on roads passing Lumpini.