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From: Don Y <blockedofcourse@foo.invalid>
Newsgroups: sci.electronics.design
Subject: Re: Speed limiters
Date: Sat, 6 Jul 2024 14:53:43 -0700
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On 7/6/2024 5:23 AM, Martin Brown wrote:
> On 06/07/2024 00:28, Don Y wrote:
>> Article in /The Guardian/ suggests these are already (optionally)
>> present in EU vehicles and soon to be *mandatory*?
> 
> They have been present as hard limits on HGVs for some time. Most HGVs are 
> limited at 56mph in the UK. Some commercial delivery vehicles also have a true 
> speed limiter and a little notice on the back to say what their maximum speed is.

That has been common on (some) commercial vehicles, for many years, here.
But, consumer vehicles have always given the driver absolute dominion over
what the car can/will do (short of exceeding its design limits).

>> But, it seems that these don't truly *limit* speed; rather, they
>> signal when the speed limit has been *exceeded*.
> 
> My car signals when I exceed the posted speed limit based on GPS info and 
> online data. It doesn't always get it right for example when there is a 
> motorway with a 70mph limit and an old urban road (30mph) running parallel. It 
> flashes the limit sign for a while if you are over it but then backs off.

I would imagine that would be annoying/distracting.  E.g., SWMBO's vehicle
indicates the presence of cars in either "blind spot" -- and "complains"
if you attempt to turn in their direction (only discovered by your propoer
use of a turn signal).

As the indicators (in her case) are near the side mirrors (which is where your
gaze should rest when attempting such a maneuver), they are relatively easy
to ignore -- UNLESS you are thinking about changing lanes/turning.

The "cross traffic" indicators that come into play while reversing are
far more distracting as they "see" things that aren't immediately
obvious in the camera view:  "What the hell is it complaining about?
THAT guy, way over there, with a shopping cart?????"

A friend has a HUD in his vehicle that displays information (including
current speed limit in the form of typical signage) *in* his front
windshield.  I would imagine that also gets distracting.

> In Japan a lot of cars have a little bell that rings incessantly when you go 
> faster than 100kph. Introduced I think around the late 1980's. AFAIK that 
> feature is physically present in UK made Japanese vehicles but is not enabled 
> in the UK.

100KPH isn't really that fast (~60MPH).  I routinely semi-legally exceed that
limit just driving through town.

>> And, can be disabled?
> 
> Probably (anything can with the right after market reprogramming). I have the 
> haptic feedback on mine disabled from the config menu.

Wheel shaker?

>> Do vehicles "tattle" on drivers that exceed the limit?  Or, is it
>> intended as a reminder (nag!) to help people drive more safely?
> 
> Potentially the airbag black box could reveal if you have been driving over the 
> speed limit in the event of an airbag triggering collision - they store the 
> last however many seconds just prior to impact to show that their decision to 
> detonate was justified.

See the article I cited in reply to Jeff.

There has been talk of using cameras and license plate trackers to infer
the speed vehicles have traveled "across town" (i.e., at XX:XX:XX you
were seen at intersection X and are now at intersection Y at YY:YY:YY;
you could only have made that trip in that time interval if you exceeded
the average speed of...")

[We recently adopted legislation prohibiting the use of automatic systems
in issuing traffic citations.  The outrage over photo-speed and stop-light
enforcement prompted this reaction (their settings were too technically
correct and folks have become accustomed to "getting some slack" from
human enforcement)]

> If you have been driving *very* quickly then the average speed log might also 
> give the game away too. Record police speeding catch on the fast section of 
> road near me was 144mph during Covid lockdown.
> 
> https://www.thenorthernecho.co.uk/news/local/northyorkshire/10979148.camera-data-reveals-a19-speed-blackspot/
> 
> A plod was done for 154mph fairly recently (I think on another road).

As most of the roads in town are long and straight (with a mile between
traffic signals -- assuming you adhere to them!), it is not uncommon for
folks to "race" in the wee hours of the morning.  And, as there are so many
potential "raceways", it is difficult for the police to crack down on
offenders -- unless purely by chance.