Motorists should avoid using two main roads in inner Bangkok where the 2015 Discover Thainess Parade will take place Wednesday from 4.30pm to 8.30pm, police said.
Pol Lt Col Chakkit Chosoongnoen said traffic will be closed on Rama I Road from Soi Chulalongkorn 5 to the National Stadium and Ratchaprasong intersection, while Ratchadamri Road will be closed from Lumpini Park to Ratchaprasong Intersection.
The parade is organised by the Tourism Authority of Thailand.
Pol Lt Col Chakkit said the parade will have a huge impact on the traffic around the Pathumwan and Lumpini areas. In total, 3.5km of inner-city streets will be closed during rush hour.
The parade will stop three times in front of stages set up on pavements. The stages will be built in front of Siam Discovery, Gaysorn Plaza and in Lumpini Park.
Pol Lt Col Chakkit, deputy chief in charge of traffic at Pathumwan station, said officials have a plan for re-routing traffic but must try to communicate it to the public.
"The most important aspect of our work now is giving as much information to the public as we can," he said, saying he wanted motorists to avoid using the two roads. Traffic signs pointing to alternative routes will be set up tomorrow morning.
He suggests those travelling from Ratchathewi Intersection towards Pathumwan Intersection turn right at Pathumwan, then either left onto Rama IV Road or right onto Petchaburi Road.
For travellers heading towards Pathumwan from Ratchaprasong Intersection, the suggestion is to turn left onto Henri Dunant or Phaya Thai roads.
Those travelling from Ploenchit intersection to Ratchaprasong will need to make a left turn into Soi Lang Suan at Chidlom Intersection.
To travel to Pratunam from Ratchaprasong will require making a left turn onto Petchaburi Road.
For those travelling from Rama IV Road to Pathumwan, motorists should turn left into Soi Chulalongkorn 12 towards Banthat Thong Road or make a U-turn before Pathumwan.
Pol Lt Col Dolchai Pinpak, a deputy chief at Pathumwan police station, said 200 police are to be deployed to oversee VIP guests' security, in addition to patrol officers. "This is a cultural event that does not involve politics, so we are not particularly worried about the crowds," Pol Lt Col Dolchai said.