NUMBER coding is one of the methods used by authorities to reduce the number of cars that operate in certain areas or roads. Under the current system for Metro Manila that covers major roads (EDSA, C5, Shaw Boulevard, Marcos Highway, etc.), a vehicle is restricted from operating between 7 a.m. to 10 a.m. and 5 p.m. to 8 p.m. on a particular day during weekdays depending on the plate number's last digit. Vehicles with plate numbers ending in 1 or 2 are restricted on Mondays, 3 or 4 on Tuesdays, etc. Motorcycles are not subject to number coding.

'Window' hours comprise the period (10:01 a.m. to 4:59 p.m.) on weekdays when number coding is suspended throughout Metro Manila (except in Makati City). Last month, the Metropolitan Manila Development Authority (MMDA) floated the idea of removing these 'window' hours. Removal will subject motorists to a more severe application of number coding. (Before finalizing its decision, the MMDA announced that it would first observe traffic conditions this week).