ALLOCATION METHOD FOR TIME SLOT, AND ROAD TRAFFIC SYSTEM

PROBLEM TO BE SOLVED: To suppress the number of necessary time slots, used by roadside communication machines in an object area, as small as possible.SOLUTION: One or more time slots among a plurality of different time slots which do not overlap with one another are allocated to a plurality of roadside communication machines installed in an object area. The object area includes: a roadside communication machine for important intersection; and a roadside communication machine for general intersection. The roadside communication machine for important intersection is allowed to use a plurality of time slots for radio communication. The roadside communication machine for general intersection is allowed to use a smaller number of time slots for radio communication than the roadside communication device for important intersection. In this case, the time slots are allocated to the roadside communication machine for important intersection preferentially to the roadside communication machine for general intersection so as to avoid interference due to radio communication that the roadside communication machines make.