In reply to a post by pluralist:

No internet connecting them. Bluetooth impossible in most circumstances at junctions. Similarly radar. A completely new method of communication required.

Yep, maybe copy how humans work; "computer vision" using cameras, augmented by radar and lidar. Have a look at Waymo in California.

Quantum entanglement to avoid crash entanglement?

Hmm!

In reply to a post by pluralist:

I expect you are well aware of sat-nav and dash-cam speed indicators lagging several seconds behind actual. GPS is of course not going to be the answer, but whatever the answer is we don't yet know.

Erm, use the car's existing speedometer, which measures the rotational speed of the wheels? It has worked well for about a century.

I don't buy the argument that self-driving cars will need high-bandwidth, millisecond-latency Internet connections. To be safe, a car needs to function autonomously - i.e. it does not need to be continuously controlled from some remote authority. There's never going to be 100% coverage of 5G, and even if there were, it would never be 100% free of outages.

Certainly a central authority could give high-level instructions, like which route to take, but that does not require continuous connectivity and it's not high-bandwidth.

Are you aware that all, or almost all, cars manufactured in the EU have speedometers that over-read by about 3mph except when the car is at rest?

This is why I normally set my cruise control 3mph high. Brilliant for passing cars on motorway-standard roads when variable speed limits are in force. Perhaps even better if I retain my current car when new ones start having automatic speed limit recognition. (All the ones I read the specs of seem to have that switchable, but that option may not survive).

My current car is about the closest of any I have owned - reads about 1mph over compared with sat nav speed calculations. Compared to street signs where they flash up the speed it is between 1mph and 3mph but as there are differences I don't think they are all correctly calibrated either.

I have had a car in the past that over read by about 5mph - that is a fairly chunky difference.

In reply to a post by pluralist:

Are you aware that all, or almost all, cars manufactured in the EU have speedometers that over-read by about 3mph except when the car is at rest?

This is why I normally set my cruise control 3mph high. Brilliant for passing cars on motorway-standard roads when variable speed limits are in force. Perhaps even better if I retain my current car when new ones start having automatic speed limit recognition. (All the ones I read the specs of seem to have that switchable, but that option may not survive).

Although my car has sat-nav the routes it gives often take the long way round so I use the Waze app on my mobile for navigation. This has a GPS speed readout on the screen. Setting the cruise control to 75 mph on dual carriageway roads means the car gives me the nag message but the GPS bounces about between 70 and 71 mph.On my routine journeys I regularly pass a number of speed cameras on 60mph and 70mph roads with the cruise control set to 65mph or 75mph and have not been pinged yet (touch wood).

Checking against the roadside screens which read your speed in 20mph and 30mph areas the GPS speed normally matches exactly the roadside display while the speedometer is over-reading by about 10%. I am making the assumption that there is a similar discrepancy throughout the speed range.

In reply to a post by pluralist:

Are you aware that all, or almost all, cars manufactured in the EU have speedometers that over-read by about 3mph except when the car is at rest?

Allows for tyre wear and slightly different sized tyres by manufacturer. Not a surprise, I believe the construction and use regs go back a very long way on that (so likely predate EU/EEC)

Separately cars since 2016 have had speed recognition and alerts, and in 2020 or so you couldn’t disable except each time you start car the visual alert. What is due imminently (maybe March 25?) is the car taking action if you speed.

The alerts and reading road signs or looking at Sat Nav OFTEN get it wrong; there’s a stretch of the M4 where a side road causes cars on the 70mph motorway to be told they are speeding all the time. 😂

Wider than EU I read - its apparently all European countries working together for driver safety; I guess some of these may be invented by EU commission.

None of this needs communications or IPv6.

The (UK) 3mph over-read is a direct result of various UN/EU et al rules, (Laws/Regulations/Directives), now existing in most or all countries. The primary reason is "road safety" to ensure that vehicles are never travelling faster than the indicated speed.

Prior to those, which ere apparently being initiated after WWII, in the UK they were allowed to indicate true speed plus or minus 2mph.

Basically the reason we now fall in with the rest of the world is just an adjustment of our early requirement to be inline with the reason in my first paragraph. Currently legislated for by the EU and incorporated into UK law as a result of our time as an EU member.

The speedo mechanism fitted to any vehicle has to be calibrated appropriately for each optional factory-fitted wheel and tyre size. A JIT assembly nightmare .

I never suggested it was anything to do with self-driving cars. The long-established forward movement in traffic and lane change alerts are also nothing to do with "self-driving", merely driver and safety aids.

You keep talking about these as though they a full self-driving feature. Obviously they will be incorporated, but a very elementary tool compared to what is needed overall.

As for traffic lights and roundabouts, I can take you to some real horrors in South Manchester where it is very easy to see/look at the wrong set of lights in front of you and also confuse drivers behind you in the lanes either side because although you follow a legitimate route and even indicate at the earliest possible time they don't expect you to turn where you do.

A self-driving car could be confused in the same circumstances.

I think the most recent regulations are in The Motor Vehicles (Approval) Regulations 1996

Section 19 reads:

1. The vehicle shall be fitted with a speedometer capable of indicating speed in mph at all speeds mph. up the maximum design speed of the vehicle.

2. For all true speeds up to the maximum design speed of the vehicle, the true speed shall not exceed the indicated speed.

3. For all true speeds of between 25 mph and 70 mph (or the maximum design speed if lower), the difference between the indicated speed and the true speed shall not exceed V / 10 + 6.25mph where V = the true speed of the vehicle in mph.

So the speedometer must not under-read but may over-read by 10% + 6.25 so the speedometer would be legally compliant if it showed 83.25mph when the true speed was 70mph. Presumably the 6.25 parameter is a conversion from 10 kph.

Edited by GonePostal (Tue 12-Nov-24 01:51:25)

The alerts and reading road signs or looking at Sat Nav OFTEN get it wrong; there’s a stretch of the M4 where a side road causes cars on the 70mph motorway to be told they are speeding all the time

Yes, they do. I have had it on 2 cars from different manufacturers. Both get the speed wrong, sometimes reading signs that are not relevant, sometimes missing speed changes on variable speed limit motorways, sometimes not updating that you have gone from a single carriageway to a dual carriageway (and not consistently even on the same bit of road at different times), etc.

Mine is set just to update so that I can set the speed of the speed limiter to match - but I do it manually. It has an option to do it automatically but it gets it wrong too often. Once they change it to default to automatic adjustment there will be a lot of people suddenly losing power or accelerating due to the camera picking up an incorrect speed.

The other issue I believe is that things like changes from single to dual carriageway use the sat nav data. I don't use the car sat nav and to update maps is an annual subscription - I don't pay the subscription so my maps will gradually get more and more out of date meaning they won't provide the additional information to the automatic speed limit recognition meaning that as roads change it won't necessarily have all the information to get the speed right.

In reply to a post by ian72:

- I don't pay the subscription so my maps will gradually get more and more out of date meaning they won't provide the additional information to the automatic speed limit recognition meaning that as roads change it won't necessarily have all the information to get the speed right.

Same... I use third party (better) sat nav solutions, with the likes of Android Auto/Apple CarPlay these are more common. I guess this is a case of FBD (Flawed By Design).

don't other EU countries have a national database of speed limits, centrally held, but in the UK local councils can change a limit by installing signs and don't need to notify anyone? Makes it hard for any technology solution to assist.