Speed limit technology

Jenni_D

The version in my Vauxhall is generally accurate, but there are times when it fails. e.g. there's a junction where you slip off the M8 westbound on to the A725 southbound. As you get near the bend of the slip there's a 40 sign which the car recognises. However as you come to merge onto the A725 the car shows the limit as 50 ... but the actual 50 sign is 1/2+ mile further down the road, so I guess it's the car's GPS overriding the last sign detection.

Google maps 40 sign location

40 repeater

Where the car changes to show 50

Actual 50 sign

tobygarrod939

You must live fairly close to where I am Jenni.

As for the speed limit thing, I only ever use this as a guide - but what is the point in the tech I see people ask? It's very useful for the adaptive cruise control as it automatically adjusts your speed as the speed limit changes - which combined with the pilot assist features, its one of a number of features that really helps to take the edge off the regular 6-7hr motorway drives. I drive a van regularly as well and miss those features when I don't have them on a long drive. On shorter or local drives, I'd rarely activate them.

The feature also warns you when you are breaking the speed limit - which as somebody who has covered over 70k miles in that car over 3yrs (and another 20-30k during that time said van(s)) - sometimes you do find yourself on unfamiliar bits of road unaware what the speed limit is  -  I find driving in the south east particularly bad for this, thus it has proven useful a few times. 

I've found the system to be very reliable (and it auto updates the maps), only rare instances like Jenni has mentioned seem to fool it.

Sandtree

troffasky said:

motorguy said:

As others have put, the technology is a guide at best.

What is the point of this technology?

You can't rely on it because sign recognition isn't 100% and the limit data from the mapping may be out of date.

If you trust it and it's wrong, you get the points, not the car, so you should never trust it.

One more bit of information consuming the driver's attention. One more system in the car to go wrong.

I can't think of an upside to it.

Ours at least was based on cameras 

To me the point was that if you missed the sign you either continue blindly or see what the car's camera saw and make a judgement call. Ultimately I know I'm the one that missed the sign as I was changing radio station or whatever so ultimate responsibility lays with me 

Advocado

I find adaptive cruise control highly frustrating as opposed to standard cruise (which I love).

When in adaptive, your driving style essentially mirrors that of the person ahead - the car brakes hard when they do.  The car can’t read the conditions ahead and lay-off the accelerator - it just hits the brakes much later.

And my VW will not overtake on the inside.  Middle lane driving is completely standard now so, after many years of driving correctly, I just can’t be bothered anymore.  So adaptive cruise means I can’t just hum along at 70mph in lane 1 because all the middle lane drivers mean the car suddenly slows to 62mph every 2 minutes.

I truly can’t see a time that self-driving cars are a thing - tech is too dumb to control a car.  

tobygarrod939

Sandtree said:

troffasky said:

motorguy said:

As others have put, the technology is a guide at best.

What is the point of this technology?

You can't rely on it because sign recognition isn't 100% and the limit data from the mapping may be out of date.

If you trust it and it's wrong, you get the points, not the car, so you should never trust it.

One more bit of information consuming the driver's attention. One more system in the car to go wrong.

I can't think of an upside to it.

Ours at least was based on cameras 

To me the point was that if you missed the sign you either continue blindly or see what the car's camera saw and make a judgement call. Ultimately I know I'm the one that missed the sign as I was changing radio station or whatever so ultimate responsibility lays with me 

And that's exactly how I see it.

Ultimately, most of my (and dare I say most drivers) speed limit awareness is based on the driving experience of surroundings and road type, rather than actually seeing and reading the signs. I do usually see the signs, but I'm not oblivious to the fact I can and do miss them for whatever reason (most often thinking a roads a 30 when it's a 40 or 50). 

That's where the dashboard display comes in handy, and yes, you make a judgement call. It's still my responsibility.

ElefantEd

Advocado said:

I truly can’t see a time that self-driving cars are a thing - tech is too dumb to control a car.  

Except that if the other cars were all self-driving, they would all be in the correct lane, and probably going at the maximum safe speed. The problem isn't the tech in your case, it's the humans!

[Deleted User]

Have a read of the manual. I bet it says don't rely on it and they are not responsible if you get a ticket.

BOWFER

Advocado said:

I find adaptive cruise control highly frustrating as opposed to standard cruise (which I love).

When in adaptive, your driving style essentially mirrors that of the person ahead - the car brakes hard when they do.  The car can’t read the conditions ahead and lay-off the accelerator - it just hits the brakes much later.

And my VW will not overtake on the inside.  Middle lane driving is completely standard now so, after many years of driving correctly, I just can’t be bothered anymore.  So adaptive cruise means I can’t just hum along at 70mph in lane 1 because all the middle lane drivers mean the car suddenly slows to 62mph every 2 minutes.

I truly can’t see a time that self-driving cars are a thing - tech is too dumb to control a car.  

I agree with you on adaptive cruise, I've used it in BMW, Land Rover, VW and Nissan cars.
Utter pain in the !!!!!! that effectively allows you to be bullied by other drivers, with your car just rolling over(not literally) and taking it.
As for driverless cars. Las Vegas has been using autonomous taxis for several years and millions of miles now.
For a while they still had a person in the driver seat, but I believe they're now completely autonomous (or the green light has been given to do this)
They also have autonomous buses.

BOWFER

tobygarrod939 said:

I drive a van regularly as well and miss those features when I don't have them on a long drive. 

Now there's an interesting point, does it take the fact you're in a van into account?
For example, many vans have a limit of 60mph on roads that would be 70mph to a car.
So does it show 60mph instead of 70mph?

tobygarrod939

BOWFER said:

tobygarrod939 said:

I drive a van regularly as well and miss those features when I don't have them on a long drive. 

Now there's an interesting point, does it take the fact you're in a van into account?
For example, many vans have a limit of 60mph on roads that would be 70mph to a car.
So does it show 60mph instead of 70mph?

It wouldn't need to, the techs in the car.