How can cellular networks improve road safety and efficiency?
Governments and the automotive industry are embracing Cooperative Intelligent Transport Systems (C-ITS) and Advanced Driver Assistance Systems (ADAS). These methods allow vehicles, infrastructure and vulnerable road users (VRU) such as pedestrians with smartphones to be connected and exchange information relating to traffic and roads. Initially, providing warnings to humans, while they will be used to support automated vehicles in the future.
Road safety and cellular networks go hand in hand. That’s because existing mobile networks with continuously increasing coverage and capacity can be used to put services into effect fast. Not only that: there are already more than 100 million vehicles on the road today with cellular network connectivity capabilities, according to this 5GAA white paper C-ITS Vehicle to Infrastructure Services: how C-V2X technology completely changes the cost equation for road operators. And the Ericsson Technology Review edition Transforming transportation with 5G indicates that more than 500 million vehicles will be connected by 2025. For road authorities, road operators and cities that aim to communicate with vehicles and other road users, the use of cellular networks is a cost-efficient option, as indicated in the above 5GAA white paper. The cost effectiveness of using cellular networks is further enhanced by the concept of “virtual RSUs” and outlined below.
Modern vehicles are equipped with advanced sensors, such as radar, lidar (light detection and ranging), cameras and so on that detect potential dangers and help to avoid collisions. Besides, communication between those involved in the traffic allows them to inform each other of any upcoming dangers, which is the key to further reducing the number of traffic accidents. Cooperative Intelligent Transport Systems (C-ITS) will allow road users and traffic managers to share information enabling them to coordinate their actions. And supported by cellular 4G and 5G networks, they will be able to transmit data with very low latency.
Connected vehicles will “talk” to each other, and to the road. This will be useful in emergency situations – for example, when informing drivers close behind a leading vehicle – which may not be visible – has had to brake suddenly. This direct kind of communication between vehicles – enabled by short-range technology – is referred to as vehicle-to-vehicle (V2V) communication.
These types of use cases also benefit from the use of long-range cellular communication to allow early warnings (anticipation), non-line-of-sight communications and redundancy of communication channels. If the communication is via the cellular network, it is referred to as vehicle-to-network-to-vehicle (V2N2V) communication. In particular, road-traffic-oriented use cases are well suited to the use of cellular long-range communication, such as when a road authority or road operator wishes to convey a temporary speed limit or indicate a zone where only electric vehicles are allowed. This type of communication when using cellular systems for communication is referred to as vehicle-to-network-to-infrastructure (V2N2I).
Of course, one of the main advantages of C-ITS services is that they enable significantly improved road safety. However, the wider benefits include increased sustainability and convenience to drivers through more efficient journey planning and fuel consumption. The benefits of these applications will not only be reaped by drivers, but also by other road users such as pedestrians with smartphones and cyclists. And the great thing about using cellular connectivity for V2N2V and V2N2I is the interoperability of different technology generations involved – so a 3G-connected vehicle and a vehicle using 4G or 5G can “talk”.
Use case trials
Ericsson has been supporting joint field trials of 4G-based connected vehicle technology in Victoria, Australia with Telstra, Lexus Australia, and local government bodies such as the Department of Transport (formerly VicRoads) and the Transport Accident Commission (TAC). These trials were facilitated by the Towards Zero road safety strategy, which aims to bring the number of deaths on the road down to zero.
Conducted over Telstra’s existing commercial 4G network, the trials focused on C-ITS “in-vehicle signage” use cases, where information is provided inside vehicles. The following use cases illustrate the benefits of C-ITS:
Slow/stopped vehicle warning
If a vehicle is driving at low speed or has come to a standstill, and the driver has switched on the hazard lights, this information is reported to an application which in turn distributes it to any vehicles approaching the area. This is especially useful when approaching around a corner, over a crest, or any other situation where the slow vehicle is in increased danger.
In-vehicle speed advisory
This enables road authorities, operators or cities to inform road users of speed limitations in a certain area. This use case was supported by a new concept called virtual road side units (RSUs). Here, a geographical zone is defined on a map, and when vehicles approach the area, information is sent to them using the cellular network. This is much more cost-efficient than installing new physical roadside equipment. The use of the virtual RSU allows for the dynamic definition of zones without the installation of hardware.
These successful trials have all been run over Telstra’s existing commercial 4G network, showing end-to-end latencies of less than 50 milliseconds in 95 percent of the tests using V2N2V, including the handling in the cloud-based application. Delivering in-vehicle signage information from the traffic management center to a vehicle using the virtual RSU was trialed with a latency of around 30 milliseconds. The trials in Australia have shown that cellular technology can support C-ITS, and when 5G becomes widespread, the increased speed and reliability of cellular networks are expected to open doors to even more advanced use cases.
Ericsson Technology Review Article Transforming transportation with 5G
Ericsson Technology Review article Distributed cloud – a key enabler of automotive and industry 4.0 use cases
Ericsson Blog Cellular V2X: What can we expect on the road ahead?
Ericsson Case Study 5G advanced driver assistance systems (ADAS)