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On dashboard speed limits, live and dynamic

How common are these on dashboard speed limit systems? Last June found that in Norway cars have dynamic, usually accurate posting of the current speed limit on the dashboard actively ticking up or down the speed limit precisely as a posted speed sign was overtaken on the road.

Now driving in New Zealand and not only does the rental car have this live in dashboard speed limit posting but the background changes from white to red when the posted speed is exceeded.

Posted by
20133 posts

I have that on my Honda Civic which is 18 months old.

I also have both a traditional cruise control and also a setting which limits the speed of the car to speed I can set and reset - no matter how far down I press the pedal the car stays at the set number. Useful in close traffic with lots of cameras.

Posted by
323 posts

Our eight year old VW doesn't have it (except on a stand-alone sat nav), but our two year old car does where, I assume, it's part of the built in sat nav and camera system. I'm guessing its just increasingly a standard feature now; generally if one marque has something the others quickly follow. The most interesting bit, I think, is that since the reported speed is based on sat nav it's noticeable how much the standard speedo overreads. Obviously it would a bit, but I was surprised that on the flat at 100kmh its around 5%.

I hope you're enjoying your holiday in NZ.

PS in terms of things cars do they never used to, I had a brand new BMW hire car a few weeks ago and it flashed up a warning when it decided I was closing too rapidly on the car in front which was breaking more than I was. And I have a colleague whose car's dashboard shows an icon of a teacup when it thinks he should take a break based on the computer's "fatigue detection" of how he is steering.

Posted by
2028 posts

I’m thinking the way this works is that someone (by hand) has taken a GIS layout of the road segments, overlain a point file of the speed limit signs, and manually assigned a speed to each road segment and the car GPS follows along— unless I am missing a shortcut.

NZ: It’s impossible to not enjoy the scenery and cool summer temperatures (here 25 C is “hot”).

2 recommendations:

  1. If you have problems sleeping on planes and don’t have $8000 for a first class bed, take Ambien! I was able to sleep for the first time on a flight. It works without causing drowsiness or a drugged feeling, it just clears the mind encouraging sleep. Even 3-4 hours of sleep makes a huge difference.

  2. Auckland International has no “bag drop” concept for international arrivals to domestic departures. So although there is a domestic transfer counter (at least 150 yds from customs arrival door and no signs) it operates identically to checking in for a fight and is just as time consuming— more so since everyone needs new flights, boarding passes, and bag tags. So the 90 min layover time in an Air New Zealand ticket cannot normally be made. I had even scrubbed off the soil on my trail shoes with bleach water to shorten the agricultural inspection and we still were 30 minutes late for our luggage re-check it. Also they say the walk from the international terminal to the domestic terminal is 10 minutes, but that’s true only if you keep a brisk pace which isn’t easy after a 15 hour flight.

Posted by
20133 posts

The way mine works is my car has several (many) cameras pointing in many directions including forward and to the sides of the road. When it sees a speed limit sign, no matter if way off the road or on a gantry or on a temporary construction sign it repeats the sign on my dashboard, in various user selectable sizes from tiny thumbnail under the computer output or on various displays, all the way up to huge - as big as the digital speedo. It also put up various important other signs when it sees them, such as No Passing.

It works flawlessly, even when a sign is covered with frost or salt.

Posted by
15217 posts

I had it for the first time on my rental car in France last fall, a Ford Fiesta, as well as GPS navigation, both automatically included. Yes, it seemed pretty accurate. I rented in Italy and Britain the two years previous without those systems.

Posted by
902 posts

Waze and some of the other systems have this too. I've found them to be very accurate. Here Maps is good as well ... one of the things I like about Here is instead of simply turning white or red, it also actually shows the current speed limit next to your current speed, so it is a little more usable.

Posted by
9 posts

I have some sort of something on my 2017 Prius that shows the speed limit as a cute little sign on my dash read outs if I choose that particular read out, and it also turns red around the outside edges when I exceed the speed limit. Funny - I thought it was just red. Then the man of the house pointed out if I just slow down to the speed limit it's white around the edges.

Posted by
29264 posts

I wasn't aware of these live speed limit systems as my 2016 vehicle doesn't have that feature. Do these also respond to situations with overhead variable speed limit signs, that change the limit according to current road conditions?

Posted by
20133 posts

mine does - and doesn't care which European country it is in...

Posted by
902 posts

Mine does not know construction speed limits. These are all tools, common sense needs to apply. It's just nice having a visual (and if you want, audible) alert if you miss the sign denoting you are entering a town or something, or knowing a speed camera is coming up.

Posted by
2140 posts

I have a colleague whose car's dashboard shows an icon of a teacup when it thinks he should take a break based on the computer's "fatigue detection" of how he is steering.

A year or 2 ago I rented a car in France that had a tea cup appear while I was driving. I believe I stopped at some point to figure out what it was all about. I thought it must be something for Brits.

Posted by
29264 posts

This website seems to provide a description of how this system works - https://www.livescience.com/10543-car-device-warns-speeding-drivers.html . The link is several years old, so I'm sure the technology has been updated since then.

With the overhead electronic signs used in variable speed limit areas, it would be very easy to use a low power radio transmitter to send the current speed limit to passing vehicles (of course that means the vehicles would need a compatible receiver). Researchers are already working on ways for vehicles to "talk" to other nearby vehicles using radio links, and that should provide a big improvement in safety.

Posted by
20133 posts

but a camera is technology which exists today and works very well thanks. I've never known it to get it wrong. In fact, it picks up changes when the posted limit changes.