Milliseconds matter for accidents, HERE and Nokia Networks explain

Ian Delaney
London 51° 30' 23.112" N, -0° 7' 37.956" E

“A few seconds gap is too long, in an accident situation,” says Uwe. “Even in optimal conditions, it would take 1-2 seconds. Too long.”

It’s an emergency. You’re travelling at maybe 70mph – much faster on some roads. Two seconds is a lifetime if you’re sending an emergency message to the cars right behind you.


Stepping back, this is what we want connected cars to do:

  • Car 1 hits a problem;
  • It automatically sends out an alert;
  • Car 2 gets a ‘brake now’ warning;
  • Car 2 sends on that warning to Car 3, and so on.

The hoped-for result: no more multi-car pile-ups on motorways.

Connected cars have a radical way to improve road safety. It’s by telling the cars behind them what’s going on. Faster than the eye can see.

UweP 1

Theory meets practice

So far, so good: we’d all like cars to be able to do that. But how does that actually happen?

We turned to an expert from our sister company, Nokia Networks, Uwe Puetzschler, to explain. It turns out the answer is not at all simple.

“On the one hand, there is a WiFi-type protocol called ITS-G5,” says Uwe.

This is a technology that’s similar to the WiFi you’re used to at home or in your office.

“This would transmit to another car within WiFi range – up to 500 metres using this protocol”.

“At night time or in remote places,” says Uwe, “maybe there isn’t a ‘Car 2’ at all, so no-one behind gets the message.”

With disastrous consequences, potentially, as cars 3, 4, 5 and so on plough into the accident spot.

An option to overcome this problem would be to transmit the signal to a roadside object, such as a receiver built into existing signs.


Sounds good? Not so good, actually. These WiFi transmitters and the cables or relays to connect them to the cloud don’t currently exist and could cost billions to implement. Unsurprisingly, no-one is very keen to put up the money to have them installed to cover the country.

Fourth protocol

Nokia Networks’ solution to the problem is to complement WiFi and use LTE more intensively for road safety applications.

While it’s still really new, LTE is very rapidly becoming universal, faster than any previous network standard.

“LTE is available pretty-much everywhere in many countries and other parts of the world are catching up quickly. Within a few years, we think it will become universal.”

A massive benefit is that the LTE network is being built *anyway*. So why shouldn’t car safety reap the benefit of that?

In addition, many top-end cars already have cellular connectivity built-in – Uwe explains:

“Today, they’re being used for sending data and infotainment but we can also use them for more road safety related purposes…”

OK, so LTE, then, but it turns out there’s a further problem.



Fifth protocol

While we spend a lot of time promoting ‘cloud’ solutions, sometimes it pays to stay more local.

“With a mobile network, the message goes from your car, to a base-station, through the network to a data centre. And then it starts out again, through the same path.”

That takes a bit of time. Too much time for some of the safety related messages.

When you SMS someone in the same room as you, they don’t get the message straightaway. There’s a few seconds’ gap, because of this roundabout route it has to take. Connected cars would face the same issue, even with special rules to prioritise their communications.

This where the extra-clever bit comes in.

“Nokia Networks is capable of deploying applications right to the basestations,” Uwe concludes.

Those basestations are no longer dumb transmitters, but powerful and fast mobile edge computers in their own right, able to adapt to the tasks they’re asked to perform – Nokia Networks calls this kind of capability ‘Liquid Applications’.

Crucially, they’re capable of turning round those emergency messages in less than 100ms. Down to less than 50ms in some circumstances.

So your car gets the emergency message from the car ahead – maybe you can’t even see it yet – in less time than it takes to draw breath.

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