It doesn't seem that long ago we were worrying about the safety of hard shoulders - too many cases slightly tired HGV drivers seeing a vehicle ahead of them in the lane to the left subconsciously thinking they must be in lane 2 and so moving left ... and crunch. So the advise if you did stop on the hard shoulder was to get out, climb any barrier and onto the grass verge a.s.a.p..

  - Andy.

One way to ease congestion would be to prosecute anyone hogging the middle lane when the inside lane is clear and those who overtake whilst travelling at 0.5mph faster than the vehicle they're overtaking. I don't think the death penalty is too draconian in either case!

Well, the problem at present is people thinking their speedo is correct . Says 70 but you are only doing 63 in the fast lane. 

I normally flash the misguided driver who usually indicates left and moves over.  As a last resort I may overtake him on the middle or even slow lane as he obviously is unaware that there is any other traffic on the motorway apart from his selfish self.

Yes, all speedos have tolerances and given that its not legal to sell a car that under-reads speed, all manufacturers set up the speedos to over-read. The % overread depends what speed you are doing and the manufacturer. Depending on how they measure speed, it can be impacted by the pressure of your tyres, wear and tear on various engine parts or sensor lag. 

However, if you driver an EV, its more efficient to go at 50-55 mph otherwise you will drain the batteries faster. Unless you have one of the rare EVs with a gearbox that supports efficient motorway cruising.

I don't think I could put up with driving that slow.  My Renault Zoe will still deliver decent economy up to 60-65 MPH.  If I'm heading home, and the "guessometer" on the dashboard reads more than the miles remaining on the satnav, then I'll stick my foot down and do 70.

When I drive past one of those speed signs that helpfully tell you how fast you’re driving and flash up a smiley or frowny face in my Audi I’m usually 2mph out (speedo says it’s 30 but sign flashes 28. In my VW it’s about 4mph out so flashes up 26 when the speedo says 30!

I used to work for the company that made the speedo in my car, so I know most of the offsets But generally I use the GPS to trim my speed on a motorway. GPS speed can still have errors.

Smart motorways are really designed for when we have V2X on most cars. That way your car can tell the system its broken down and alert other cars in the vicinity. Although, like any new technology, it will take time for that to be adopted by the majority of vehicles. Most of us don't change cars every couple of years.

I used to work for the company that made the speedo in my car, so I know most of the offsets But generally I use the GPS to trim my speed on a motorway. GPS speed can still have errors.

Smart motorways are really designed for when we have V2X on most cars. That way your car can tell the system its broken down and alert other cars in the vicinity. Although, like any new technology, it will take time for that to be adopted by the majority of vehicles. Most of us don't change cars every couple of years.

Smart motorways are really designed for when we have V2X on most cars.

and that too will fail spectacularly when network connectivity is lost - its all about building intentionally brittle systems - and if you are not careful you are also designing in attack vectors for malcontents to use as well. Look at the effect of GPS and cellphone jammers for example, and their use already in more organized robberies...

Mike.

Agreed - especially if when they look at the Use Cases for the system they look at the "Sunny Day" scenarios only and forget to look at all the ways the system can fail.

But if you look at all the ways the system can break, can be misused, there are plenty of methodologies that allow the design of a more robust and resilient solution. The real question is, putting in secondary systems costs extra money, will anyone want to pay?

I don't see V2X rolling out other then little test schemes anytime soon (and yes, I know about the ring road near Birmingham) - that will need a massive infrastructure roll out for roadside transponders plus it will most likely take at least a decade for the majority of cars on the road to be fitted with the appropriate onboard equipment.

As far as I am aware Vehicle to everything - V2x at the moment is really just tests of roadside Wifi or telephone mobile data, and will first be used for collecting tolls and so forth. I suspect as soon as it gets used to record time of transit data, odd hacks will appear to modify the time stamps so your speed over ground is not so easily deduced..

Mike.

Most lorries and some taxis are fitted with electronic loggers which record time, speed and GPS location.  If these figure were transmitted to MofT then spying on everyone would be possible but not beneficial as it misses the main cause of accident which is tailgating and not keeping within safe braking distance.

It was a bit more than tolls - here you go: Connected car testing goes live in Coventry as part of UK CITE Consortium | Coventry University

Unfortunately it looks like the funding run out and this is no longer active.

Like Mark Tickner above, I tend to trim my speed, particularly in average speed zone stretches using my sat nav.  I have also checked the speedo on my VW, which matches the smiley face signs and sat nav at 30 mph, and also suggests that speedo 70mph is sat nav 63.

I travelled today from West London to Devon via the M3/A303/A30.  The M3 smart motorway stretches worked well, traffic running smoothly although quite heavy, and I felt safe.  Four of the emergency laybys had broken down vehicles, two being attended by breakdown services.  Where I did feel unsafe was a non-smart section where at 65mph (sat nav) in the inside lane a very heavy lorry tailgated me, to the extent I took steps to get behind it; also in a single carriageway section of the A30, in a line of traffic travelling at 40mph, a Range Rover insisted on tailgating.  In my view it is poor drivers that cause the trouble by not driving according to the road conditions, whether or not the technology is working.  Using technology to try to correct it will fail at some point.