If an autonomous car break the speed limit -who takes the blame?

Autonomous Cars are the great hope of the car industry, ironically, to solve all problems that cars have created: congestion, safety, parking, etc. It's also an obsession with google -maybe in a misguided belief that it will solve problems, more likely that they want to get all those extra hours people spend in traffic -browsing time.

Ignoring the technical issues -will they work- there are legal issues -and that's something cycling and road safety campaigners need to sort out -before the decisions are made for them.

Start with a simple question: If an autonomous car break the speed limit -who takes the blame?

This is a simple question but gets complex fast.  Today, if a car breaks the speed limit, the driver takes the blame. The driver is expected to be aware of what type of road it is, and what extra road signs show restrictions on the mandated maximums: 50 mph, 40, 30, 20. There are even temporary speed limits -those on motorways are still enforced.

It doesn't matter whether speed limits are long-standing, temporary or recent -if you break them, you take the blame.

Yet lots of people do break the limits, to the extent that if you drive round Bristol at 30 mph drivers behind you start to get impatient and then frantic. Drive down the end of the M32, where it's become 30 mph -you'd have a bus go into the back of you.  And as for the M5 to Birmingham: 85 is the minimum speed in the fast lane.

The defacto speed limits of much of S Gloucs and Bristol are higher than what's legal -the reason people drive at those speeds is because they get away with it. Which is why there's so much hate of speed cameras. Everyone views it as their right to drive at 85 mph down a motorway,  35 in town. Speed cameras don't catch one or two speeders -they force the speed limit down by 15 mph.

But speed camera or police camera: driver is always guilty.

Now, what about Autonomous Cars?

If they can be configured to break the speed limit, if there is some "break the law" button, what would that mean? That drivers have the option of telling the car to break the law -and if so, they are liable? But even building such a feature in means the car manufacturer wink-wink providing an overtake option "to use in emergency" -exactly the same way they hint about how cars can drive at 130 mph "in Germany".

The alternative: you can't speed in autonomous mode, you have to go manual -how is that handled? Does the a-car log this fact and speed? They'd have to: because if the car got caught speeding in manual mode, then the fact it wasn't in autonomous mode is something that'd be used by the car manufacturer as a defence.

But what if the car broke the speed limit in autonomous mode? If you are driving there is no excuse for doing so -and you take the hit: points and penalties. What happens in automatic mode? Does Ford or Google take a hit? Does the driver who was reading email get blamed for the actions of their car?

And how does the car know the speed limits?

Drivers have the road and its signed, but a-cars are going to have to rely on digital maps with speed-limit data on it. How often are those maps going to be refreshed? When a new 20 mph zone is rolled out, can a-cars break the limit until they get an update? And who is at fault then? Is it an "oh well never mind" problem? Is the fault of the driver? The map updaters? Or even the council? After all, today's GPS units have a big disclaimer "don't rely on this" -which is precisely what autonomous cars plan to do.

It gets better thought: in france the speed limits on autoroutes changes depending on weather -that's officially, not just "Slow down in the rain" hints.

Nominally then, an automatic car could break the speed limit in france even if the map was up to date -because it wasn't aware of the weather.

These all sound theoretical questions -but if they don't get answered the likely outcome will be "if an autonomous car breaks the speed limit -never mind". That will be especially in the case in changed limits, permanent or temporary. While drivers could get penalised, the fact that autonomous cars break the limits until the maps are updated is something that could become accepted as inevitable.

No doubt car manufacturers will also be pushing for higher limits for a-cars on motorways, say, 85 mph in dedicate lanes. Which is what they will know they have to in order to preserve the defacto 85 mph limit, to sell autonomous driving on motorways.

Yet from a road safety perspective, this question, who takes the blame when an autonomous car breaks the speed limit, is critical.

Because the answer to that will shape the answer to the next question: if an autonomous car kills someone: who takes the blame?