Preferences of the ambulances and public transport in Ústí nad Labem

ZZS preferences

Since October 2020, a test deployment of the preference of the regional ZZS (Health Ambulance Service) vehicles in Ústí nad Labem is in operation. This was the first deployment of this type of preference (ZZS), with which there was no experience so far. As in the case of the HZS in Brno, the V2X communication is secure and the certificates used are recognised at European level. This prevents unauthorised misuse. In addition, hybrid communication is used, where messages are sent both via V2X and LTE connection. This ensures maximum system reliability. In cooperation with NTD, on 21.10.2020 we equipped 2 intersections with RSUs (Road-Side Unit) at the hospital in Ústí, namely:

• Social Care - Mezní (near the hospital) (K12)
• Social Care - Krusnohorská (K11)

Both RSUs are connected to the Cross controllers.

One vehicle ambulance and one OBU - UCU 5.0V unit. The second vehicle ambulance was installed in the month of June 2021. Due to the fact that both RSU intersections are close to the regional hospital, the preference of the ZZS is much used. The average number of daily trips with the EMS preference is about 10 times per day at each intersection (the preference is active along with the beacons on). In terms of utilization, this is probably one of the most heavily used intersections in the country. The results achieved for the first two and a half months of operation in 2020 were very interesting. Below are the preference statistics for the intersection - Social Care x Krusnohorská, namely the average speed of the crossing and the number of crossings. The table shows that the highest number of preferences was used at the hospital exit. Logically, the highest speed is from Belogradska Street (70 km/h) because the car was going straight towards the hospital and did not need to brake. Another very interesting statistical result was the increase in the average speed of the ambulance vehicle through the intersection from Belgrade Street with time after the drivers got used to the system working. The graph shows that the speed of passing through the intersection increased by about 10 km/h.

Preference of public transport vehicles

In addition to the preference of ZZS vehicles, we have piloted the preference of 2 public transport vehicles of the Transport Company of the City of Ústí nad Labem a.s. on two vehicles in June 2021. For this purpose, we have equipped the vehicles with standard UCU 5.0 units for public transport and a converter for "interception" of data from vehicle buses. Accordingly, the unit acquires the necessary data for communication with the intersection.

After less than two months of trial operation, it can be stated that this has been very successful. Public transport preference through the above intersections was only via V2X communication, with a delivery reliability of more than 98% (can be further increased by supporting LTE communication or by modifying the algorithms).

A graph of intersection crossings is shown below:

Conclusion

The test operation shows that the ambulances gain valuable seconds for saving human life when passing through an intersection. In the case of public transport, the preference means fuel savings and a smoother ride, especially when using controlled stops. In addition, RSUs broadcast the intersection controller's signal plan so that any vehicle with V2X can adopt the plan. Thus, the pilot operation of V2X communications in Ústí nad Labem offers essentially a complete set of urban C-ITS services usable today.