It is useful to know the feature of each media, Radio wave beacon and Infrared beacon that are installed on the roads,
and FM multiplex broadcasting that can provide information far and wide, by making use of FM radio wave.
| FM multiplex broadcasting | Radio wave beacons | Infrared beacons | |
|---|---|---|---|
| Transmission device | FM multiplex broadcasting | Radio wave beacon (roadside unit) | Infrared beacon (roadside unit) |
| Receivable location | transmission range | Expressway | Ordinary trunk roads |
| Frequency/wavelength | 76-90 MHz | 5.8 GHz | --- |
| Data capacity | 50 KB | 25 KB | 10 KB |
| Transmission rate | 16 Kbps | 4 Mbps | Downlink 1 Mbps / Uplink 64 Kbps |
| Receiving area | 10-50 km | 20 m | 3.5 m |
| Repetition of providing information | 2 times / 5 minutes | 2-3 times / 1 receiving | |
| Effective information amount | About 50,000 characters / 5 minutes |
About 25,000 characters / 1 location |
About 10,000 characters / 1 location |
| Contents | - Information about a prefecture of each staion - Expressway information as far as about 100 km away |
- Expressway information as far as 1000 km away from a beacon - Congestion avoidance support - Safe driving support (combination of graphics, images, and audio) |
- information about ordinary road as far as 30 km ahead, and 1 km backwards from a beacon. |
| - Conditions near interchange | |||
| Level 3 Map display type |
Congestion, link travel time (Expressway Information), interval travel time, restrictions, parking lot | Congestion, link travel time (Expressway Information), interval travel time, restrictions, SA/PA infoamation | Congestion, link travel time, interval travel time, restrictions, parking lot |
| Level 2 Simple graphic display type |
Congestion, interval travel time, restrictions | Congestion, interval travel time, restrictions, SA/PA information | Congestion, interval travel time, restrictions, parking lot |
| Level 1 Text display type |
Congestion, interval travel time, restrictions | Interval travel time, restrictions, SA/PA information | Congestion, interval travel time, restrictions, messsage information |