Driverless cars, mph and km/h

[c2R]

Possibly... In the volvos different downloads of software and maps are available for different continents.... I didn't take it with me to America though so didn't have the opportunity to find out!

[Octaviadriver]

Mine picks up circular speed limit signs with red borders, but not the temporary rectangular yellow speed limit signs that are sometimes used, though I believe these are unenforceable. It's supposed to pick up no overtaking signs as well, but I haven't seen one in my current car yet as they're rarer than hens' teeth. I'm taking the car abroad in four weeks, so maybe I'll find out then.

It senses which country you're driving in and will adjust your headlights automatically between left and right hand traffic, so it can't be that difficult for it to know when signs are in miles per hour or kilometres per hour.

[A9NWIL]

Well as far as i know anything with "historic vehicle" as it's taxation class is exempt from the ULEZ and that has now started rolling again at 40 years - so if you keep your Skoda long enough you can drive her through London again - along with a really dirty smoky early 70's Landrover etc

True that will be fun! I look forward to that day I hope the old girl survives that long. I guess it depends on if I can keep the rust off as most other things can be fixed, but rust would be a death-knoll.

[Reading]

How do the auto reading systems cope with issues like this https://goo.gl/maps/oS2TjNM5QLE2 30mph sign just off the motorway on parallel rd

[Octaviadriver]

How do the auto reading systems cope with issues like this https://goo.gl/maps/oS2TjNM5QLE2 30mph sign just off the motorway on parallel rd

Mine occasionally picks these up. I've set a warning next to the sign display (visual but not with sound) if I'm more than 6mph over the limit and this will show on the display incorrectly in these circumstances.

The warning would be more useful if you could set it as a percentage of the limit rather than a fixed number across all speed limits.

[Chris Bertram]

How do the auto reading systems cope with issues like this https://goo.gl/maps/oS2TjNM5QLE2 30mph sign just off the motorway on parallel rd

Mine occasionally picks these up. I've set a warning next to the sign display (visual but not with sound) if I'm more than 6mph over the limit and this will show on the display incorrectly in these circumstances.

The warning would be more useful if you could set it as a percentage of the limit rather than a fixed number across all speed limits.

There's a LILO side road off A435 SB as I'm heading for M42 that has a 30 limit. The terminal sign is angled round to face traffic turning into the side road as they turn, and my vehicle picks this up, suggesting that from there to M42 is a 30 limit rather than NSL 70.

[Reading]

These are the reasons that the idea muted a few years back that vehicles should be fitted with speed limiters that would recognise a speed limit and brake the vehicle were fought so hard by motorcycles (Plan was called ISA and norwegian led as part of their project zero). When you brake whilst turning on a bike it stands up and understeers, different bikes are affected to greater or lesser extent depending on geometry - but if whilst going around a corner your bike decided it was suddenly in a 30 not a 60 due to the issues mentioned the resulting unexpected change in direction could be deadly. NONE of the research teams had a solution that could work around it at the time

[c2R]

I believe the volvo system combines both the readings from the road signs as well as the GPS location and track, so it would know where you were. I'm not sure what happens where there is a difference, either from out of date signs or VSL.

[Reading]

I believe the volvo system combines both the readings from the road signs as well as the GPS location and track, so it would know where you were. I'm not sure what happens where there is a difference, either from out of date signs or VSL.

The quoted accuracy for GPS in the UK is 4.9m under open sky - that is more than enough to give a false speed limit reading in the location i posted above

[c2R]

I believe the volvo system combines both the readings from the road signs as well as the GPS location and track, so it would know where you were. I'm not sure what happens where there is a difference, either from out of date signs or VSL.

The quoted accuracy for GPS in the UK is 4.9m under open sky - that is more than enough to give a false speed limit reading in the location i posted above

Yes, but computers are fairly clever, and so the sat nav system would know where you have come from and would be able to make an educated guess about which road you're more likely to be on. In the same way that their in car GPS "works" while you're in the Dartford Tunnel - it knows how fast you're going and where you've come from, and how much further you have therefore to go....

[Reading]

mine regularly has a complete fit and has me driving in a field near the road i am actually on etc - if yours doesn't lucky you. And that is with mine meant to be using gps and cell tower triangulation

[A9NWIL]

These are the reasons that the idea muted a few years back that vehicles should be fitted with speed limiters that would recognise a speed limit and brake the vehicle were fought so hard by motorcycles (Plan was called ISA and norwegian led as part of their project zero). When you brake whilst turning on a bike it stands up and understeers, different bikes are affected to greater or lesser extent depending on geometry - but if whilst going around a corner your bike decided it was suddenly in a 30 not a 60 due to the issues mentioned the resulting unexpected change in direction could be deadly. NONE of the research teams had a solution that could work around it at the time

I guess some kind of detection system would be needed to stop it braking when the bike is leaning would be needed, or that it would just stop any acceleration instead and allow the bike to slow with engine braking instead. The latter would mean that for a few 10s of metres that the bike could be breaking a speed limit, but it would soon slow down.

[Helvellyn]

mine regularly has a complete fit and has me driving in a field near the road i am actually on etc - if yours doesn't lucky you. And that is with mine meant to be using gps and cell tower triangulation

The rather old one built in to my car is only ever wrong about the road I'm on when it doesn't have any information to make it more precise. What it appears to do is assume that I've not left a road at random on an unknown to it turning and started driving through fields - this is most obvious when a layout has changed since the DVD was made, and it'll stick to the old route for a little while before deciding that I really can't be there and gives up and draws me driving across wherever.

[Johnathan404]

I saw a system fitted to a Volkswagen Golf (probably after-market, I didn't think to ask) over five years ago which displayed the current speed limit on a UK-style speed limit sign. Metric countries would have their speed limit converted before being displayed, meaning you would see a UK-style sign with 80.78 on it.

This was actually a clever way of getting around the nuisance of having to remember which dial to look at, but as I wouldn't put complete faith in it I wouldn't get the convenience of that.

[A9NWIL]

I saw a system fitted to a Volkswagen Golf (probably after-market, I didn't think to ask) over five years ago which displayed the current speed limit on a UK-style speed limit sign. Metric countries would have their speed limit converted before being displayed, meaning you would see a UK-style sign with 80.78 on it.

This was actually a clever way of getting around the nuisance of having to remember which dial to look at, but as I wouldn't put complete faith in it I wouldn't get the convenience of that.

I dont have to worry about that as I use only metric in my car anyway, I know what each mph point is in km/h and work off of that, its a digital speedo so I get an exact number.

[Octaviadriver]

How do the auto reading systems cope with issues like this https://goo.gl/maps/oS2TjNM5QLE2 30mph sign just off the motorway on parallel rd

Mine occasionally picks these up......

I've just remembered another situation where it picks up an incorrect limit is from countdown markers ie 30mph in 300 yards. It assumes the 30 limit starts as you pass the countdown sign.

[Reading]

These are the reasons that the idea muted a few years back that vehicles should be fitted with speed limiters that would recognise a speed limit and brake the vehicle were fought so hard by motorcycles (Plan was called ISA and norwegian led as part of their project zero). When you brake whilst turning on a bike it stands up and understeers, different bikes are affected to greater or lesser extent depending on geometry - but if whilst going around a corner your bike decided it was suddenly in a 30 not a 60 due to the issues mentioned the resulting unexpected change in direction could be deadly. NONE of the research teams had a solution that could work around it at the time

I guess some kind of detection system would be needed to stop it braking when the bike is leaning would be needed, or that it would just stop any acceleration instead and allow the bike to slow with engine braking instead. The latter would mean that for a few 10s of metres that the bike could be breaking a speed limit, but it would soon slow down.

What they concluded was that any system for bikes could not be attached to the brakes at all and would only be able to stop acceleration not effect a deceleration - shutting the throttle fast on my gpz900r had the same understeer issue as front braking due to it's abnormal 16'' front wheel and steep steering head angle.

[Vierwielen]

I saw a system fitted to a Volkswagen Golf (probably after-market, I didn't think to ask) over five years ago which displayed the current speed limit on a UK-style speed limit sign. Metric countries would have their speed limit converted before being displayed, meaning you would see a UK-style sign with 80.78 on it.

This was actually a clever way of getting around the nuisance of having to remember which dial to look at, but as I wouldn't put complete faith in it I wouldn't get the convenience of that.

I dont have to worry about that as I use only metric in my car anyway, I know what each mph point is in km/h and work off of that, its a digital speedo so I get an exact number.

When South Africa went metric, most drivers were able to convert between mph and km/h. The change was almost overnight with no dual speedos anywhere. The Arabs and the Israelis helped the education part of the changeover by engaging in one of their spats a year after the change-over. This resulted in a world-wide fuel crisis. The South African Government's response to cut back on fuel consumption was to impose a 80 km/h blanket speed limit and heavy fines for those who transgressed (probably £500 minimum in in today's money). That encouraged those motorists who had mph speedos to learn their conversions quickly.

[Reading]

Adaptive cruise control not great at spotting bikes either

http://www.bmf.co.uk/news/show/adaptive ... orcyclists

[A9NWIL]

Adaptive cruise control not great at spotting bikes either

http://www.bmf.co.uk/news/show/adaptive ... orcyclists

That proves it, true driverless cars that dont require a driver to step in are a very long way off!