Posted on October 11, 2016

How can the car industry ensure reliable vehicle-to-vehicle communication? In an op-ed for 2025AD, an expert demands: Make ITS-G5 the road safety connectivity standard for vehicles.

 Public debate on connected and autonomous driving (including testing & deployment scenarios) seems to mainly focus on cellular communication networks. Cellular communication is an essential piece of the greater vehicle connectivity puzzle. It connects the vehicle to back-offices/clouds and provides the big picture to the autonomous vehicle. It has to fit with ITS-G5, the other piece of this puzzle, though. ITS-G5 provides the reflexes of the vehicle through connecting it directly with other vehicles and the infrastructure.

Cellular communication is essential for autonomous driving. Cellular communication is capable of transporting large volumes of data, such as maps, billing information, traffic advice (non-time critical), infotainment, convenience applications, that autonomous vehicles need and that are not time-critical. An autonomous vehicle has to be able to “hold its breath” though, in case of no cellular network coverage. Its subliminal reflexes have to still work without a cellular connection. An essential requirement, since most big automotive markets, such as the US or the EU have not achieved full 3G or 4G cellular coverage yet and may take some time doing so.

If back-offices and clouds are the metaphorical brain of the autonomous vehicle, the autonomous vehicle also has a hippocampus, that allows instant reflexes  in any situation, because vehicles are capable exchanging time critical road safety information directly.


The autonomous car can be compared to an individual body with a nervous system providing the ability to instantly, subliminally so to say, react to threats. This nervous system fed by its sense of “sight” (laser, radar, cameras, ultrasound), its “hearing” and its ability to “speak” (ITS-G5).

Platooning: one of the uses cases for ITS-G5. (Photo: Kapsch)

A human has two lungs, two kidneys and so on; safety is about improving the perception of our environment, as well as having a spare set of the most essential things. An autonomous vehicle uses a range of technologies such as radar, laser technology, cameras and ultrasound to grasp its environment. These are the “eyes” of the autonomous vehicle. The vehicle has to interpret the information these sensors provide within a split second to decide which action to take. Fog, dust, heavy rain, snow, slush, bright light are some of the factors these sensors have to deal with and consider in their interpretation. Like our eyes these sensors rely on the line of sight. Like our eyes, sight is suited for some conditions better than for others.

That is why we have a sense our hearing complementing our eye-sight. Ships sound foghorns in thick fog, because sound traverses the fog, in a way light or sight can’t. ITS-G5 is a microwave technology, loosely related to WLAN, that offers autonomous vehicles a sense of “hearing” and the ability to “speak”. ITS-G5 enables autonomous vehicles to communicate with each other directly and instantly beyond the line of sight. This communication is the fastest available and allows vehicles to react instantly in cases of immediate danger. ITS-G5 is ETSI standardised in Europe and mature. Its American sister technology WAVE is also standardised and  the preferred road safety communication technology of the US National Highway Traffic Safety Administration NHTSA.


Ironically, to become autonomous a vehicle depends on cooperation with other vehicles and the road operator. It has to “speak” and be “social”. Vehicles can warn other vehicles that they are close, yet not in sight, around a corner, say. To run autonomously vehicles have to coordinate precisely and develop a “social behaviour” like in the case of platooning (for energy efficiency, as demonstrated in the European Truck Platooning Challenge). For this vehicles have to speak and react instantly. The road operator is responsible for traffic management and hence may want to listen into its roads and the traffic there. In the future the road operator may take a role similar to that of an air traffic controller for roads. Road operators play a key role avoiding radio interference between ITS-G5 and tolling systems.

The European Truck Platooning Challenge was held in 2016. (Photo: MAN)

Therefore we need a clear recognition and acceptance of ITS-G5 as the road safety connectivity standard for vehicles, since parts of the system will require certification. The sooner this is recognised, the sooner cars will get safer and autonomous. It is the only technology that fulfils technical requirements for safety: such as speed or the independence of network coverage, whilst at the same time going hand in hand with cellular technologies needed for other ITS applications. With this recognition issues such as security, privacy, interoperability and freedom of radio interference can be addressed and solutions for product certification found, finally allowing the autonomous vehicle to drive autonomously and safely.

Only an inclusive view of the autonomous driving will deliver the levels of safety, security and privacy a vehicle requires to become autonomous.

Date: Sep 28, 2016
Author: Richard Lax