[Closed] What would be the problem with technologically-enforced speed limits

It would be pretty easy to hack too.

It needs to be solid enough as evidence in court also.

[pistonheads] I need freedom to use my awesome skills to accelerate out of trouble even if that takes me over the speed limit [/pistonheads]

Personally seems like a good idea. My car knows what the speed limit is on most roads based on GPS, although some it doesn't have data for. It can also use the cameras to identify speed limit signs and use that.Gets it right about 90% of the time. Guess we just need to fill in the gaps and we're good to go.

[pistonheads] I need freedom to use my awesome skills to accelerate out of trouble even if that takes me over the speed limit [/pistonheads]

Yeah, I was expecting that, and I'll be honest I though it might be a valid argument. I can't think of a specific scenario though.

They (well new ones) are in Japan arent they, a blanket 112mph limit, unless at a track?

The “accelerate out of trouble” argument is  defeated with suitable exceptions.

e.g. you are allowed to exceed the limit for up to one minute (with suitable warnings)

Personally I like the idea that the limit isn’t enforced but exceeding the limit causes the car to turn off the stereo, and Bluetooth, and start blocking mobile signals.

Wouldn’t want you distracted would we?

Perhaps it could also make a suitably annoying noise to indicate the issue.

I'd be interested.  I think an even better application for this would be smart road network with GPS limiting to a max "journey speed".  e.g. you feel like going fast, or even 40 in a 50, but there's a red light or roadworks ahead, or just town centre traffic.  There's actually no point going any faster than 15mph, any faster and you'll just get to the back of the queue quicker.  15mph is your "journey speed" for that stretch of road.  If you want to get past that cyclist because he's "holding you up" you'd learn via you lack of throttle response that he's already going quicker than your "max journey speed"

Or you're doing 65 mph on the motorway in traffic and tailgating the one ahead, because you're in such an important hurry.  Well, more congestion ahead means that 54mph would mean you'd there at the same time, so that's what you're going to do.

Maybe you'd chill the **** out.

They (well new ones) are in Japan arent they, a blanket 112mph limit, unless at a track?

If so it begs the question of why they didnt set the limit to the highest legal limit of 100kph.

The biggest problem would be the majority of voters wouldn't like it.

Car manufactures wouldn't like it and they drive the economies of very large influential countries like Germany, Japan and the US.

Safety wise, speed kills, yeah, driving like a **** causes accidents and kills people, but frankly most cars these days are incredibly easy and safe to drive, you can't really crash a modern car at 20-40mph unless you do something really stupid, like daydreaming about Christmas or whatever when you should be driving, or looking at their phones. What would happen is this, after a few weeks of getting used to the system, people would simply hold their foot on the throttle pedal letting the cars speed be controlled by the limiter and switch off even more than they do now.

I'm kind of against having to legislate for every damn thing. And it would only take one instance of "my loved one/whoever would still be alive if the car had allowed them to accelerate".

<span style="font-size: 0.8rem;">But people do seem to be incapable of adhering to rule 1...</span>

What would happen is this, after a few weeks of getting used to the system, people would simply hold their foot on the throttle pedal letting the cars speed be controlled by the limiter and switch off even more than they do now.

That'd be my main concern.

I'd rather they installed stuff that communicated with the DVLA every time someone tried to start a vehicle and wouldn't let it start unless VED and Insurance were in place and the driver had a licence. Vehicles shoudl also record their position on GPS at all times and be able to be read remotely in the event of a collision where/when they were somewhere to ascertain if they were involved.

I realise this is an active measure and relies on good comms but in most urban and suburban areas it wouldn;t be a problem and the car coudl wait until it established comms before checkign and then refusing to restart the next time it was used until overridden.

There's 5000 hit and runs in London every year - reducing those is probably more important than enforcing speed limits, imo, because those who'll run arte usually those already breaking the law.

Oh, and doesn't this become a moot point when fully autonomous cars become the norm, anyway?

As above - too many variables for it to work. My car often tells me its a 70mph speed limit but I am in the middle of the road works on the M1 with a 50mph limit etc etc.

Anyone know what the proportion of car related deaths are caused by exceeding marked speed limits?

As well as declaring the limit is 70 in a 50 zone, mine often tells me I'm in an old set of 50mph roadworks on an open 70mph stretch of motorway.

Or is having a fit telling me I'm permanently speeding on the autobahn in a section where there's an 80kph section parallel, but 130kph limit on the main carriageway.

If the technology is going to be used for penalties and prosecution, it's going to have to be a damn sight more tight evidence than that.

I like the idea of needing proof of VED, MOT and insurance in order to start the engine though.

Anyone know what the proportion of car related deaths are caused by exceeding marked speed limits?

15% according to "RAS50001: Contributory factors in reported accidents by severity" in RRCGB 2016

Third highest contributory factor in fatal accidents after "Loss of control" (30%) and "Driver/Rider failed to look properly" (27%).

What would happen is this, after a few weeks of getting used to the system, people would simply hold their foot on the throttle pedal letting the cars speed be controlled by the limiter and switch off even more than they do now.

Then after a few more weeks they would all be off the road having their cars straightened out, as would the poor sods they'd driven into.

Anyone know what the proportion of car related deaths are caused by exceeding marked speed limits?

Problem is there isn't any way of compiling a statistic for "deaths caused by being a dick", but speed can be measured, and there's probably a high correlation between speeding and being a dick, and breaking other rules (tailgating, not indicating, phone usage, eating toast, etc).

Problem is now that they've clamped down on speed to a fair degree, those people just eat toast and update facebook at the speed limit (as long as there's a yellow box on the roadside or Waze is telling them there's a police car ahead).

We're going to have to solve all of these 'well the road next to this one has a different limit' type issues for autonomous cars to function properly so once that's happened then applying it to vehicles with human drivers will be possible?

I was at a conference in Gothenburg about this and automated vehicles last week. My brain still hurts.

In terms of ISA the obstacles to its implementation are largely political (as with almost all transport projects , see cycle paths/ car free city centres, congestion charging etc etc )    Everyone thinks they are experts (see above and below 🙂 ) and it would be met my opposition despite the evidence ... flame on...!

3 types of system are being looked at, advisory, driver select and mandatory, coupled with fixed , variable or dynamic speed limits types.

massive sweeping statement but it is thought deaths , injuries and fuel consumption would decrease, (more or less depending on type of system) whereas system implementation costs are huge, but these are balanced by cost savings elsewhere. i.e. you no longer need to build anything to create a 20mph zone. The actual technology is fairly simple.

15% according to “RAS50001: Contributory factors in reported accidents by severity” in RRCGB 2016

Third highest contributory factor in fatal accidents after “Loss of control” (30%) and “Driver/Rider failed to look properly” (27%).

so not a reason not to. but what i would expect is that it wouldn't be in addition to traffic police. it would be instead of.

which would arguably make the roads more dangerous.

As above – too many variables for it to work. My car often tells me its a 70mph speed limit but I am in the middle of the road works on the M1 with a 50mph limit etc etc.

Yes, but it's just a "nice to have"/"best endeavours" add-on that the car manufacturer has given you (like the cup-holders so you can drink coffee and drive). It would be necessary to create a definitive system dictated by the powers that be to implement this putative scheme.

Maybe because there’s no political will to do it? Who’d stump up the cash to plug the hole left from speeding fines and the economy dependent on catching speeders (smart motorways anyone?)

it wouldn’t be in addition to traffic police. it would be instead of.

What traffic police??

I think it could potentially dangerous unless implemented carefully.

Accelerating out of trouble is a viable manoeuvre - I've done it before now, below the speed limit I believe, and happy to explain the circumstances if anyone wants to tell me I'm wrong - and if a situation develops where I suddenly need to hit the loud pedal then the last thing I want to do is bounce off a speed limiter.  A system which generally limits speeds but is smart enough to recognise an atypical emergency might work I suppose.

The other argument is driver attentiveness of course, which we discussed on another thread recently.  If you give a driver less to think about, do they focus more on other things or do they pay less attention generally?  I think the answer might be "it depends," which gives us something of a quandary.

As well as declaring the limit is 70 in a 50 zone, mine often tells me I’m in an old set of 50mph roadworks on an open 70mph stretch of motorway.

A few folk have said similar here.  Technology exists now where cars can read the road signs (I think the new Mondeo has it) rather than rely on potentially out-of-date maps.

What other areas in life would you be happy to let technology enforce rules?

I like the idea of needing proof of VED, MOT and insurance in order to start the engine though.

The problem here is that the people most needing this would be the people most likely to bypass the system.  Like the prick on a trials bike who nearly rode into my car the other day - on the wrong side of the road, on one wheel, two-up with no helmets.  He's totally going to have a VED immobiliser fitted.

What other areas in life would you be happy to let technology enforce rules?

Train Operation.

Aircraft Operation.

Boat Operation.

Lorry drivers driving hours.

Preventing theft from stores by means of an audible warning of shop lifting at the exit doors.

Doctors Prescriptions and access to controlled drugs.

etc etc

He’s totally going to have a VED immobiliser fitted.

and you have to have sufficient punishment for not having one and the certainty of being caught without/with a bypassed one to make it not worth even trying.

Or you’re doing 65 mph on the motorway in traffic and tailgating the one ahead,

I like the idea of your car slowing down by itself in this situation.  I'd also force the washer jets to shoot the driver in the eyes with soapy water if they flash their lights at a car that's passing a long stream of HGVs, but not at their desired 95 mph.

Technology exists now where cars can read the road signs (I think the new Mondeo has it) rather than rely on potentially out-of-date maps.

So when I drive my German registered car to UK, I'd be well safe, being limited to doing 60kmh in a 60mph zone 😉

No limit signs in 30 zones.  It'd have to remember from the previous journey, as well as using GPS. Even more complicated if a 20 zone (although I think those are not legally enforced?).

The technology is easy, definitely. It's just the exceptions that make it complicated.

What would be the problem with technologically-enforced speed limits

IMO, massively increased complexity and potential of reduced reliability, esp as these theoretical vehicles progress through the second hand market, combined with only very marginal justification for such a system. Gross speed is only a causal factor in a small proportion of accidents, the vast majority of traffic is now largely speed compliant, and your proposed system would almost certainly increase the incidence of ‘due care and attention’ RTCs.

All that being said, the ‘speed out of trouble’ argument could be easily worked around with an indented accelerator pedal and an irritating bonger that goes off whenever over the limit.

in fact, rather than a limiter, a bonger that goes off constantly if speeding in a similar fashion to the now compulsory seat belt warning bongers would be a much more palatable alternative maybe?

-posted from my iPhone whilst driving at or below the speed limit*

*not really but you get my point

What traffic police??

i read about them in a book...

 It’s just the exceptions that make it complicated.

they really don't

Of course we are putting all this on the car, which perhaps is the wrong approach.

We already have a solution for this, that would work on all cars, can't be easily bypassed by the driver, and would allow for "accelerate out of trouble": average speed cameras.

It doesn't have to be universal - once a certain percentage of cars are traveling at the speed limit it's impossible to speed for more than a few hundred metres.

The technology is easy, definitely. It’s just the exceptions that make it complicated.

But that stuff will need to get sorted out for autonomous vehicles anyway. Whether that means additional signage, better GPS speed limit maps, some kind of local limit broadcast system or some combination of the above.

It will happen at some point but likely after autonomous cars are mainstream. We'll have smart roads with variable limits everywhere depending on time of day, weather conditions, proximity to a school etc. We'll all essentially be passengers not drivers.

Even more complicated if a 20 zone (although I think those are not legally enforced?).

ACPO guidelines (IIRC) suggest that the police generally won't actively enforce 20 zones.  However, they are legally enforceable just like any other mandatory limit.

I like the idea of needing proof of VED, MOT and insurance in order to start the engine though

That's a pretty awful idea for those of us who live in areas with poor mobile coverage, though. And any kind of external system that allows you to stop a car is a massive risk,  it would be a huge target for hackers. So no.

I think it's viable so long as, as others have said, it doesn't prohibit the opportunity to accelerate out of trouble.

Not being a driving god like some, occasionally I have misjudged an overtaking situation, for example overtaking a car doing 50 in a 60 and finding it taking longer than anticipated. At that point it's far safer to put the foot down and get by as soon as possible, even if that means I break the limit.

I personally think that the potential for cars to be on the wrong side of the roads for longer offsets the benefits of automated speed limits.

When my wife is in labour, at 02:30hrs and needs to get to a hospital double quick, and no ambulances are available due to cutbacks, you can stuff your autonomous speed limits up your 'arris, thank you very much!

I'd hazard a guess that your pregnant wife would be in a lot more danger from the erratic driving of a panicking sleep-deprived father-to-be than she would be from the actual labour.

When my wife is in labour, at 02:30hrs and needs to get to a hospital double quick, and no ambulances are available due to cutbacks, you can stuff your autonomous speed limits up your ‘arris, thank you very much!

[irrelevant anecdote]Not that I called an ambulance, but when my wife went into labour at 02.30 on Christmas Day morning I was looking forward to my 90mph journey to Guildford. Annoyingly, mrs njee20 demanded smooth over fast, and as such I never got to enjoy the completely deserted roads. Sad times.[/irrelevant anecdote]

I personally think that the potential for cars to be on the wrong side of the roads for longer offsets the benefits of automated speed limits.

Maybe if people know they wouldn't be able to 'accelerate out of trouble' they wouldn't make chancy overtaking maneuvers?

[edit] or perhaps brake and pull back in rather than going ever faster in a bid to get past at all costs?

Personally I like the idea that the limit isn’t enforced but exceeding a limit causes a spike to protrude the drivers rectum

FIFM

And I like the idea of remote VED/Insurance/MoT on vehicles whereby if any one of the three arn’t satisfied the vehicle drives itself off Beach Head locking the doors on the way and thereby disposing of the Meat Popsicle in the drivers seat.

👍🌤

Like I quite like the idea that anyone caught speeding in built up areas has thier vehicle crushed whilst the owner & driver watch and get charged for the disposal process too.

exceeding a limit causes a spike to protrude the drivers rectum

That'd only encourage some folk.

Perhaps a spike emerging from the centre of the steering wheel would be more effective?

Or disable the air bags if you are more than 10mph over the limit and let Darwin do the rest?

Maybe if people know they wouldn’t be able to ‘accelerate out of trouble’ they wouldn’t make chancy overtaking maneuvers?

I doubt it'd make much difference TBH.  Did people drive more cautiously before the advent of airbags?

I wonder whether road safety would increase or decrease overall if we replaced the drivers' airbag with a 6" steel spike in the middle of the steering wheel.

Jinx.

Cougar: if you haven't read it then take a look at the book "Risk" by John Adams, especially this page:

https://books.google.co.uk/books?id=dui_qLXcPa0C&lpg=PP1&pg=PA154#v=onepage&q&f=false

His website is worth a read too:  http://www.john-adams.co.uk/

The essential argument is that people automatically balance risk in both directions to their own acceptable level:

Increase the risk by putting a spike on the wheel and they reduce the risk back down by driving slower.

Reduce the risk by making a road straighter, wider or better lit and people increase it again by driving faster.

Imagine how much more annoying it would be to get stuck behind one of those 40 in a 60 types...

Not much of a downside, but the only one I can think of... (except...)

Actually, as I was typing I thought about my cycle commute along a long straight A road. It's a 40 limit and people take chances to overtake when there's something coming the other way fairly often. If they were speed restricted I reckon I'd get a hell of a lot more close passes than I do now. It usually being the slower cars, who are next to me for longer, who don't get past before they pull in. Especially vans, lorries and buses and (as per thread a while ago) tractors.

So I think full automation, not this half arsed version.

Not being a driving god like some, occasionally I have misjudged an overtaking situation, for example overtaking a car doing 50 in a 60 and finding it taking longer than anticipated. At that point it’s far safer to put the foot down and get by as soon as possible, even if that means I break the limit.

Has anyone ever had to accelerate themselves out of a problem they didn’t get themselves into in the first place?

Why do you need to break the speed limit to drive a pregnant woman to hospital?

As already mentioned, autonomous vehicles are going to make this argument irrelevant.

Anyone know what the proportion of car related deaths are caused by exceeding marked speed limits?

From memory, as the primary cause, 4%. Inattention number one cause. That was for KSIs, not just fatalities.

Has anyone ever had to accelerate themselves out of a problem they didn’t get themselves into in the first place?

Yes. I would almost certainly have been killed a number of times if I hadn't been able to accelerate past trucks driven by people who are apparently unable to check their mirrors before suddenly changing lanes.

Because a speed limit doesn't indicate a safe speed that the road can be driven at...its a limit, for example a lot of twisty country roads have 60mph speed limits, but are nowhere near safe or able to be driven at 60mph. So what do you want to limit?...the ultimate speed, which may be unsafe for the road or the conditions of the day so utterly pointless, or the safe speed that you can drive that road?

Also we've got the safest roads in the world and speed is not the cause of most crashes (although crashing at a higher speed will increase chances of serious injury or death)...typically it is driving too close to the car in front and people not paying attention. We're only so fixated on speed because it is easier to tackle and generates a nice amount of revenue. We've got a lot of bigger causes of death on our roads, and in our wider society, to deal with before we get down to the last half a percent of causes of death. It's about focussing resources on the biggest hitters...assuming of course you're genuinely interested in reducing road deaths. You can't tackle everything simultaneously.

Ultimately when we have self driving cars in the not too distant future, it wont be an issue, so as soon as that happens the better...not because people will be enforced to travel at 'safe speeds' but we will remove the real problem on our roads of people simply not paying attention and driving too close to the car in front.

Personally I like the idea that the limit isn’t enforced but exceeding the limit causes the car to turn off the stereo, and Bluetooth, and start blocking mobile signals.

I'd happily take that. Except perhaps on motorways. And just limit the speed in towns please.

Re. accelerating out of trouble, you might have someone doing 55 on straights but going incredibly slowly round corners. Wouldn't fancy trying to overtake without exceeding the speed limit but it would get frustrating being behind them for any period of time.

Maybe a button you could press to make the car in front slow down when you're overtaking to complement the speed limiter?

I suppose the other factor as with many laws is that it's kind of seen as "It's not ok to do unless you do it at somewhere nobody cares". You'd be taking away the ability to do that, think cheeky trails etc. The law's always been made in the knowledge that it's to give the right impression, not necessarily be followed religiously. I think to enforce the law without loosening it a bit would make many unhappy.

Main argument against is the contract would be managed by crapita or some of the other idiots. So huge expense and all the 30mph roads would register as 300mph and the motorways as 7mph.

Cars are already speed limited on smart motorways, it still doesn’t stop accidents.

Whats wrong with doing 150mph on a deserted road ? That in itself is not dangerous

you might have someone doing 55 on straights but going incredibly slowly round corners. Wouldn’t fancy trying to overtake without exceeding the speed limit but it would get frustrating being behind them for any period of time.

If the only way to get past is to break the law then don't try and get past? What's it going to cost you - 5 minutes on a journey?

What other areas of the criminal law do people feel it's appropriate to ignore on a regular basis and at their own discretion?

Imagine how much more annoying it would be to get stuck behind one of those 40 in a 60 types…

Yeah, sorry.. that’s me right there. I annoy plenty of people and that’s not restricted to posting on here 🤪🤷‍♂️

I’d quite like to see all vehicles have a scrolling information board fitted to the rear of the car, say on the boot where it’s easily visiable.

On the scrolling information screen can be narrative that the driver dictates or perhaps a system narrative or even a remote narrative that’s come from HAL or something.

The scroll narrative could then issue “back off big boy I’m driving at the regulated speed limit” or “of mouth breather, stop texting and concentrate on piloting that steel people killer you are sat in” or “Moron, yip you in the white van, yip you.. back off sunshine otherwise I will report you for driving without due care and attention” or “Mummsy, stop feeding your kids in the back seat whilst you apply makeup.. you need to get up earlier or take proper control of the offspring you’ve brought into this world” or “BMW driver.. B.M.W DRIVER, YES YOU THE TYPE FACE IS IN BOLD BECAUSE  I KNOW YOU DO NOT LIKE BIG NOR COMPLICATED WORDS SO BACK OFF AND STOP PRETENDING TO BE DAMON HILL”

You get the gist.

One especially for truck drivers “**** off you ****er”

From memory, as the primary cause, 4%. Inattention number one cause. That was for KSIs, not just fatalities.

That's not the way the STATS19 recording works as I understand it. It identifies the contributory factors involved. It doesn't identify a primary cause. Here's the form they use:

Whats wrong with doing 150mph on a deserted road ? That in itself is not dangerous

Correct. The dangerous thing is assuming it is deserted.

A world in where no one is killed in an RTA but we all die of boredom 🙂

That’s not the way the STATS19 recording works as I understand it.

Not now but I'm going back some way. It was around the time the "one third lie" was being trotted about.

It wont happen. Just thing of the millions in revenue the government would loose if speed cameras became obsolete

My co car is tracked & speeding is flagged up  -- we have been advised that speeding is a disciplinary offence - I have no idea where the limits are set but acts as a bloody good deterant I can tell you.

What other areas of the criminal law do people feel it’s appropriate to ignore on a regular basis and at their own discretion?

I don't have pedal reflectors on my bicycle. I do have a bright LED lights and reflective clothing trim.

Not a patch on my great grandfather though, he never once attended archery practice. What if the french had invaded? Got a nice medal in WW1 as a pilot though.

Take them as more guidelines than hard and fast rules.

I like to use the goldilocks argument for driving. I think I said this last year in the snow (that would be great with our auto speed cars doing 60 on black ice)

If you're going faster than everyone, you're probably wrong; if you're going slower than everyone, you're probably wrong too. Keep in the middle, and you are allowing real time mass data collection and experimentation to determine your best course of action. Not just speed, you can apply it to other things like slip road merging and so on.

My co car is tracked & speeding is flagged up  — we have been advised that speeding is a disciplinary offence – I have no idea where the limits are set but acts as a bloody good deterant I can tell you.

my old company had pool cars that did this. Sent an email to your line manager. someone got 70 in a 30, threatened with instant dismissal, the works. Worked out it was from a motorway passing over a 30mph road when quite a lot of other people got the same. Took months to sort out the software (if it ever got sorted). at least it was an email, not slamming the brakes on for you on the M4.

ayjaydoubleyou wrote

My co car is tracked & speeding is flagged up  — we have been advised that speeding is a disciplinary offence – I have no idea where the limits are set but acts as a bloody good deterant I can tell you.

my old company had pool cars that did this. Sent an email to your line manager. someone got 70 in a 30, threatened with instant dismissal, the works. Worked out it was from a motorway passing over a 30mph road when quite a lot of other people got the same. Took months to sort out the software (if it ever got sorted). at least it was an email, not slamming the brakes on for you on the M4.

I worked on a vehicle tracking system for a while that did this sort of thing. In the case of what I worked on it worked by the tracker having a SIM and sending data like position, speed, acceleration etc... back to the server. The server then did the clever stuff like speed limit checking and geofences (for speed limits it was using google speed limit data and the lat/lng of the vehicle), it was usually pretty accurate but certainly not perfect.

I worked on a vehicle tracking system for a while that did this sort of thing. In the case of what I worked on it worked by the tracker having a SIM and sending data like position, speed, acceleration etc… back to the server. The server then did the clever stuff like speed limit checking and geofences (for speed limits it was using google speed limit data and the lat/lng of the vehicle), it was usually pretty accurate but certainly not perfect.

this was roads crossing over, so exact same lat and long. despite the previous 1000 and subsequent 1000 data points being on a 70mph motorway heading east/west, one point on a north south 30mph road was enough to trigger the alert. Maybe it has got cleverer.

Mebbies everyone should just download the Aviva App and be done with it.

Obvz, that App is faultless and accurate and the data hived off it isn’t used for any other purpose than tracking the driver and then applying some humongous algorithms to apply some “driving god” logic and sprinkled with fairy dust for added “god” status.

No stats are available from Aviva about people who speed or break the law, because obviously that’s private data and shouldn’t been seen by anyone other than the driver and the company..

Yeah, yeah right.

Has anyone ever had to accelerate themselves out of a problem they didn’t get themselves into in the first place?

Yeah, me.

Cars are already speed limited on smart motorways, it still doesn’t stop accidents.

I thought the point of of smart motorways was to improve traffic flow, not reduce accidents.

If you’re going faster than everyone, you’re probably wrong; if you’re going slower than everyone, you’re probably wrong too. Keep in the middle

There's a term for this, 85th percentile.

But wouldn't there be a danger of an outbreak of penile shrinkage amongst the petrolheads?

as these theoretical vehicles progress through the second hand market

I see a future where there isn't a second hand market as we know it; rather, the leasing model will continue to expand and only the very rich will own their own cars…

I would also expect that every scrap of data that is generated as we go about our business in our cars is ruthlessly exploited by the private sector company that holds the road contract in order to offset their running losses because they underbid in order to win the govt contract in the first place.

Imagine how much more annoying it would be to get stuck behind one of those 40 in a 60 types…

They can do 40 in a 60 as much as they want, makes them relatively easy to pass when it’s safe.

When they do 40 in the 30 through the next village or the 20 past the school, because they are selfish morons of enormous magnitude, that’s when it starts to vex me.

as a side effect it also makes them harder to pass safely, because I’m often hundred of metres behind once the speed limit changes, so takes a while to catch them again.

The problem would be ****s pretending that they need to break the speed limit to "accelerate out of trouble".

So Im driving my speed limited car down a 60 mph road at 60 and come round the corner into a 30 mph. At this point presumably my car is going to automatically do an emergency stop to bring my speed down to 30. The chap following me also at 60 comes round the corner to find my car doing its emergency stop to get me from 60 to 30 but hasnt started its emergency stop yet because the car says it doesnt need to yet.