The bike rally will start at and return to Sanam Luang.
The 8am-8pm campaign aims to encourage people to refrain from using personal cars to cut use of petrol, plus reduce noise and air pollution. Organisers will also ask people for suggestions to solve the problem, while a mini concert will be held on the main stage. City transport agencies will offer free services and people can also use a free tram and borrow one of 300 bicycles to attend the rally. So far over 20,000 people have registered for the activities on www.carfreeday2015.com.