The mourning for King Bhumibol will take on a special dimension on Saturday with a huge gathering at Sanam Luang to sing the Royal anthem for the beloved late monarch.
The Bangkok Metropolitan Administration predicts that hundreds of thousands of people will fully occupy Sanam Luang and the area in front of the Grand Palace by Saturday afternoon to join MC Chatrichalerm Yukol, a national artist and filmmaker, who is recording the event for posterity.
"The Sanam Luang area can handle about 100,000 people and that could be enough," deputy city clerk Wanthanee Wattana said on Friday.
Metropolitan police have installed 16 more closed-circuit TV cameras in addition to the 16 already in place around Sanam Luang for the safety of the crowds. Almost 40,000 soldiers have been deployed in the vicinity to join about 1,000 police officers to secure the area.
Pol Lt Gen Sanit Mahathavorn, the Metropolitan Police Bureau (MPB) commissioner, said on Friday that another 1,000 officers would be called up for reinforcements on Saturday.
One of the concerns for authorities is traffic gridlock if too many people attempt to reach the area by private car. Traffic conditions could get worse as more mourners from around the country are coming to the Grand Palace to pay their respects over the three-day holiday weekend.
People who want to take part in the historic mass singing event are strongly advised to leave their cars at muster points outside central Bangkok and take shuttle buses to Sanam Luang.
The key parking locations are Impact Muang Thong Thani which can accommodate 5,000 cars, Phutthamonthon (1,000 cars), the construction site of the Bangkok Mall (400 cars), Central Plaza WestGate (4,000 cars) and the Police Club (450 cars), according to the MPB's traffic control centre.
The Bangkok Mass Transit Authority is providing buses that will travel between the five areas and the event venue.
"Motorists should avoid all roads around the Grand Palace and Sanam Luang if possible," said Pol Maj Gen Jirapat Phumjit, the acting MPB deputy chief .
The mass singing will begin at 1pm with the anthem played by the Siam Philharmonic Orchestra. The resulting film of the event will be shown on television and cinemas across the country.
The orchestra featuring about 100 instruments and a choir of 100 voices will be conducted by Somtow Sucharitkul.
Those wishing to take part are being asked to be at Sanam Luang by 10am for rehearsals. Participants are asked to wear black and bring one candle each.