
Pol Maj-General Jirapat Pumijitr, deputy metropolitan police commissioner, said this was a pilot project being tested for 15 days.
All the vehicles, including private cars, taxis and tuk-tuk will not be allowed to use Rama I Road from 4pm to 8pm.
The test was initiated after a survey of the road and vicinity found that the heavy congestion on the road during those peak hours was largely caused by cars destined for nearby department stores and by vehicles turning at the many intersections.
The traffic snarls on Rama 1 Road resulted in the congestion of other roads, said Jirapat.
He said all the vehicles from Pathumwan to Rachaprasong intersections will have to turn right at Chalermpao Intersection to Henry Dunant Road and to Rama IV road.
Vehicles from the Central World department store would turn right to Rajdamri or turn left to Prathunam Intersection and turn right to Phetchburi Road.
Police will evaluate the result of the pilot project after 15 days, Jirapat said.