The road traffic information, or VICS information is edited and processed in VICS center is transmitted to each car navigation equipment via ''beacons' or ''FM multiplex broadcasting' devices which is installed on various roads across the country. There are two types of 'Beacon', one is 'Radio wave beacon' on expressways, the other is ''Infrared beacon'' on major ordinary roads. 'FM multiplex broadcasting' provides wide area information, and 'Beacons' send necessary and detailed information about nearest road condition based on the position where the car is moving.
Radio wave beacon
Radio wave beacon can provide information about expressways, a by-path near interchanges, and neighboring ordinary roads, in a range of about 200 km ahead from the car.
This information tells you the condition of traffic congestion, link-travel-time on expressway, regulations, SA/PA information, interruption, interval-travel-time between interchanges, etc.
The navigation equipment can receive radio from your running direction within 70 meter radius from each beacon.
receivable within about 70m
diameter of a beacon
Infrared beacon can provide information about expressways and ordinary roads as far as 30 km ahead, and 1 km behind from the car.
This information tells you the condition on traffic congestion link-travel-time, regulations, parking lot information, interval-travel-time, etc.
The navigation equipment can receive signal from running direction within 3.5 m from each beacon.
receivable within a range of about 3.5m in near side of beacon
FM multiplex broadcasting
FM multiplex broadcasting can provide information about the prefectures you are in, neighboring area and regional borders.
Multiplexed with audio broadcasting from NHK FM stations, the information is sent in the same frequency band.
The information is transmitted twice five minute to ensure reception, with the data of 50,000 characters per 2.5 minutes.
e.g. The service area of VICS Tokyo (82.5MHz)
(Each service area is almost the same with that of NHK-FM. It covers major cities across the country.)