V2X for municipal road network managers

RSU at intersections

The V2X technology brings new possibilities that can increase traffic security and efficiency on municipal roads and mainly at intersections. V2X will make broadcasting of intersection controller plans which will make it possible for vehicles to react by adjusting their speed to go right through when the green light is on. At the same time RSU will be able to warn drivers in the vicinity about extraordinary traffic situations – closures, maintenance etc.. V2X also has a significant influence on increasing the efficiency of emergency services and public transportation – it is possible to provide preference to such vehicles at intersections by using one technology. Our solution makes all this possible. It is also possible to install OBU in road management vehicles. These vehicles will inform drivers when e.g. a road is being cleaned. On top of all that, all this will be realized as per international standards ensuring compatibility among individual manufacturers.

We offer both intersection units (RSU) and OBU units for vehicles to meet the needs of municipal road network managers. RSU are typically placed on intersections and they communicate with intersection controllers to ensure correct functionality. Our RSU is fully compatible with controllers produced by the Cross company. Our solution meets the requirements of both the Czech and the European C-ROADS project. We equipped intersections on important Brno roads with 12 RSU units as a part of this project.

We are one of the biggest suppliers in the field of public transportation preference via V2X in Europe – we supplied the city of Brno with almost 80 RSU units for public transportation preference. This prefernce has been functioning reliably for quite some time.

We offer solutions of the following situations by using V2X:

• 

  A Brno fire engine driving through an intersection with preference

  ES vehicle preference – if a controller unit is equipped with an RSU unit and an ES vehicle with an OBU unit the vehicle can request preference at an intersection. The preference is granted by setting the green light in the direction of the ES vehicle arrival while other directions have the red light. The ES vehicle can drive through the intersection safely. The preference request is processed by the RSU. Our goal is to simplify ES vehicle  passage as much as possible while minimizing the preference duration to minimize the impact on other traffic. All exceptional situations are solved in cooperation with intersection controller units. Read more about preference in this article.

• Public transportation vehicle preference – this preference also requires installation of an RSU at an intersection and of an OBU in a vehicle. Based on a command from an on-board computer, the OBU sends a preference request that is relayed to the controller unit by the RSU. The controller unit uses the RSU and the OBU to send a reply to the on-board computer. Our solution is prepared for bidirectional vehicle-controller unit communication and thus for situations when an intersection controller unit actively sends commands to a vehicle. We use SRM and SSM messages for communication but it is also possible to use CAM messages. Read more about preference via V2X here.

An example of a departure instruction sent by a controller unit via an RSU and an OBU (meaning via V2X) that was displayed in green on a display of an on-board computer

• Signal plan broadcasting – thanks to cooperation with an intersection controller unit an RSU unit broadcasts a signal plan via MAP and SPAT messages. This can help with e.g. optimizing the passage speed of various vehicles such as public transportation vehicles.

Display of SPAT and MAP messages sent by an RSU unit based on communication with a controller unit. The green light is in the west-east direction while the red light it in the north-south direction.

• Roadwork warning – our OBU units can be installed in vehicles performing roadworks. The units are connected to vehicle flashing lights and can broadcast a roadworks warning message when the flashing lights are on. It is also possible to specify the roadworks type.
• In trucks our units make it possible to read the CAN busbar (standard J1939) and thus enabling us to send operation information from the vehicle to the dispatching. Our system offers significantly more information than a classic „fleet monitoring“ solution which is only based on the vehicle position which we can send as well.
• Connection with an application on a tablet – the V2V application not only displays received warning messages but can also be used to manage and setup on-board OBU units. It displays all received vehicles and RSU on a map together with places of events. It can also be used to set a drive regime (winter maintenance, etc.) or a vehicle type (gritter, . . .). If an exceptional event is detected it can also be used to create a warning message.
• RSU units can be connected to Back Office – be it our BOS or even somebody else‘s. In this way units can broadcast warning messages that cannot be obtained locally (e.g. based on meteorological data or information about planned closures).
• RSU units detect all vehicles with V2X in their vicinity so they can be used as traffic state detectors. Unlike classic induction loops they monitor vehicles the whole time they’re in the vicinity and they obtain information about average speed or direction (the vehicle broadcasts its state the whole time). When connected with Wi-Fi and Bluetooth detectors from the Cross company they can also count vehicles not equipped with V2X.

RSU units

RSU units – consisting of our unit UCU 5.0I – they are usually placed at intersections. Their task is to broadcast warning and information messages to the passing cars, broadcast the state of the signal plan and react to preference requests from ES and public transportation vehicles. RSU exchange information with intersection controller unis. They can also obtain traffic information – collect and aggregate data about passing vehicles – they receive their CAM messages. Besides V2X data aggregation RSU can also be equipped with a Wi-Fi and Bluetooth detector (supplied by the Cross company) enabling the unit to obtain traffic information from vehicles without V2X.

To ensure simple installation and service we supply our RSU units as „all in one“ devices meaning that the unit is ready to be installed on a traffic light column. It only needs to be provided with:

• Power supply – 12-24 V
• Ethernet for communication with a controller unit

In case it is not possible to connect the controller unit and RSU by using an ethernet cable we prepared a solution using 4 regular conductors (type Cy-Ky) or only 2 conductors. Even in such limited conditions we guarantee reliable and sufficiently fast connection to a controller unit and also a dispatching or a Back Office server. RSU can be connected to a controller unit without changing the intersection installation.

Our RSU can also be used with already existing preference systems. Thanks to the RS-485 connection we are able to send data to a controller unit in a form it expects. We substituted radio modems  on intersections in Brno in this way and communication runs via V2X. Old controller units registered no change as they keep receiving packets in the expected form. New controller units use Ethernet.

In Ostrava we performed a  test where the then current radio modem was replaced by an RSU. The RSU in combination with an OBU successfully dealt with the bidirectional communication and the test was a success.

The basic unit characteristics are:

• V2X antennas have profit of 12 dBm
• Units are equipped with an LTE modem for connection with a central server – a UCU unit can also behave as a router and provide other units (e.g. a controller unit) with server connection
• Ethernet busbar for connecting other devices
• GNSS for obtaining position and accurate time

OBU units

We offer our OBU units UCU 5.0V in a number of versions with various mechanical configuration and various equipment. The typical UCU 5.V equipment includes:

• V2X communication – supporting antenna diversity for better reception, or two-channel operation.
• Mobile internet connection – LTE – for connection with a central Back office server and for secure V2X communication certificate updates. Two independent modems possible.
• Position sensor – GNSS (GPS, Galileo and Glonass) – for accurate position and time
• Accelerometer and gyroscope for better position estimation and non-standard situation detection
• Wi-Fi access point – to connect a tablet.

There is an option of equipping the unit with two Ethernets to connect other vehicle devices. Besides this busbar the following busbars can be used to meet road manager needs:

• CAN – for reading vehicle drive data – our unit supports the J1939 standard of usage in trucks. Thus the unit can obtain information about speed, tire pressure, vehicle revs, consumption, … This information can be sent to a server.
• One-bit inputs – for information about other vehicle signals  – warning cart state, flashing lights on a maintenance vehicle or a gritter …

Our unit have a permission to be installed in vehicles. They are ready to be installed in cars and trucks including specialized vehicles for cutting grass, etc.