Can we talk about connected cars? They might not excite you but as far as the industry and lots of governments are concerned, they are a pretty big deal – or they’re going to be.

Not just yet, though, because connected cars – or co-operative intelligent transport systems (C-ITS) if you prefer – have hit a developmental crossroads.

The next step-change in advanced driver assist system (ADAS) technology and increasingly adept levels of autonomy will be made possible by the widespread adoption of vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-pedestrian (V2P) and, as a handy catch-all, vehicle-to-everything (V2X) communications.

Today’s ADAS functions and Level 2 autonomous systems, such as Tesla’s Autopilot and Audi’s Traffic Jam Pilot (whose Level 3 billing has been dialled back a notch in most countries for now) are limited by what the vehicle’s own sensors can detect, which currently extends to a useful forward range of 250-300 metres on a good day. V2V communication could expand on that massively by allowing cars to share data on relative speeds, positions, directions of travel and even driver control inputs. Mix all this together and it will be possible to create a much more detailed picture of the surrounding area and make driving safer. Or at least that’s the idea.

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As an extension of V2V, V2I will add information from traffic lights and signals, variable speed limits and congestion monitors to enable a freer flow of traffic. Throw in V2P and V2X, including cloud-stored information on anything from the weather to the nearest available parking space, plus data sent via smartphones in people’s pockets, and we’re on our way to a fully autonomous, accident-free utopia. Or at least that’s the idea.

But for this to happen, the industry still needs to reach a consensus on how all of this data will be transmitted and shared.

Originally it looked like a system using an agreed wireless local area network standard known as IEEE 802.11p, commonly referred to as dedicated short-range communications, or DSRC, would win favour. DSRC would allow V2V communication and a V2I interface via roadside beacons (although it’s never been clear who would pay for, operate or maintain those). In the US a frequency was allocated for transport use as long ago as 1999, then it received approval for the same in Europe in 2008.

More recently the DSRC option has been overshadowed by C-V2X (‘C’ standing for cellular) C-V2X was originally conceived using the LTE 4G mobile phone network but has since evolved to encompass the almost-imminent 5G rollout. One of the appeals of C-V2X is that it introduces the possibility of adding pedestrian and cyclist data via smartphone integration, which DSRC wouldn’t allow. In terms of hardware and infrastructure, C-V2X’s LTE technology has no compatibility with DRSC – the two systems are mutually exclusive – “hence the dilemma,” says Colin Lee, Jaguar Land Rover’s V2X manager.