Could this make a safer and better driver in the city traffic?
Who wants to pay fines for a moment extra over speeding, while there is too much to watch for in city traffic?
If you like paying massive fines, then forget about all this and , ENJOY (losing money)!

I found these when trying to find a car vehicle compass accessory.
HUD (Head Up Display) , is a small until with a projector onto the windscreen showing both GPS info and or OBD (car computer OnBoard Diagnostic info) info.
It's main use is showing the speedometer up on the windscreen glass, but also time that can be obtained GPS , speed GPS and compass (heading) GPS.
I bought two cars over a year back, one had a GPS compass built in it's console (Captiva CG SX), the other did not (Subaru Outback) , both are almost twenty years old.
While investigating for an accessory vehicle compass (for city driving) I came across HUD units with windscreen projectors, and includes GPS speed alarm too.
Considering 40kmh for the alarm solved a large point because of school zones and many suburban streets rebranded heavy pedestrian and bicycle traffic into 40kmh streets, it makes perfect sense for speed, alarm setting 38kmh , satellite GPS calculated time and GPS compass for long cross city driving. Too the new default urban road speed limit is 50kmh so it's a good warning from the alarm if you don't notice your acceleration.

The Captiva had a compass inbuilt 2007 , but these devices (HUD) prove weight in gold in GPS mode!

Should this service be standard in all cars?

You don't want to get booked speeding particularly by simple overspeed, you don't want long drives of over 10kmh in strange areas finding you only went round in some type of giant circle!

Update note
Just found the C5 model has an RPM alarm, great for the old rattle-traps I drive to not overdo the engine!

NB , apart the speil about oil and RPM in the video, I bought a stage 2 clutch with flywheel, I will install along with the other4.11 ratio dual range.
The stage 2 is because OEM clutches get damaged with prolonged high RPM use after clutch mid life, the pressure plate levers and housing get stretched, so I got a super heavy duty street legal able to take over 500 Nm. It's because 2nd gear in city traffic is capable of over 60kmh, so an RPM alarm setting is extremely valuable!

Changed the video to tell better insight, sorry it's all at 3AM in the morning.
These are my cars and my trial at my expense in the video

A bit about..
?si=wQZNuBD_m9vPPgi2

Standard in my area should be an underspeed alert

Fkn infuriating 3 lanes across doing 10kph under the limit for no reason

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Mark _australia said..
Standard in my area should be an underspeed alert

Fkn infuriating 3 lanes across doing 10kph under the limit for no reason

Minor dispute to that... with three lanes , the problem is the new default speed is 50kmh and the updates(context of how often can be seen) of road speed signs is often scant for 1/2 a km after getting onto any road , but there are plenty of 3 lane inner city or 2 lane (2 for either direction) now with 50kmh (some with 40kmh e.g. Sydney park at Snt Peters on its Northern side is two lane) , the speed signs are often painted on the road at the end or entry intersection!
Wonder if you've been speeding.

Added : Disclaimer against misinformation in the Linked YouTube video in the OP about HUDs.

NOTE: Of video purpose relating the RPM alarm function (about clutch torque damage or engine oil engine damage) in the C5 HUD ,
(Referring to using 20 Litre drums DIY)
The video mentions fleet engine oil Top Dog global CJ4 as more suitable against Top Dog CK-4 !
This is not quite as simple as one or the other point!
EXPLAINED...
That is only because car manufacturers mainly recommend only using "full synthetic engine oil", AND the CK-4 variety is only made in "15w 40 mineral engine oil" ,whereas, the Top Dog global CJ4 is made in "both 10w 40 , and 15w 40 semi synthetic".

If your vehicle engine is able to use mineral engine oil as stated by the vehicle manufacture and the cold-hot test numbers of 15w-40 align sufficiently, then CK-4 is the (better quality) superseding product CJ4.

Mate I was talking about the freeway and other arterials with same limit all the way. trust me. Perth grrrr

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Mark _australia said..
Mate I was talking about the freeway and other arterials with same limit all the way. trust me. Perth grrrr

WOW! I have never heard of such an affordance on any Australian roads , you are at least then outside (my guess) the inner city areas!
In Sydney, I drove from CBD to Mount Druitt near the Blue Mountains a few times recently and it's 3 lanes with a fourth breakdown lane, on either direction speed is regulated to three different levels depending passing suburbs or commercial industrial areas ,70 or 80 or "90 or 100" , but there are traffic lights as you belt along these aka four lane size roads.
WA govt. designers must be completely different!

======. The HUD video description (updated)
And how to use RPM alarm for "mixed fleet oil"

With this system (RPM control) I can get 2x 20L barrels of long period "mixed fleet oil" will last 3 years at lower top of the range product for 47AUD per change or 70AUD per change near the absolute top.

NOTE: Of video purpose relating the "RPM alarm function" in the C5 HUD , This video mentions "mixed fleet" (multi fuel diesel and petrol) engine oil "Top Dog global CJ4 "as more suitable against "Top Dog CK-4" (However, for those only comfortable with passenger vehicle mixed fleet Syn-X 6000 can be found in Australia from some suppliers at reasonable cheaper cheap skate price and as closer fit 5w-40)!
warning: Also use ONLY oils that suit legal pollution emission standard treatments (of your countries laws).
mentioned below are oils suiting mixed fleet (petrol diesel) for post 2002, 2007 and updated upgraded oils post 2007 , 2014 "vehicles emission control systems" (CK-4 and Synfleet MX(emission Syd. 2014-18 approx.) ) are the only two present date qualifiers, others are for most 2007 standards.
(Referring to using 20 Litre drums DIY, At being a cheap skate , prices from suppliers vary but can be found cheaper, unfortunately Synfleet MX is both uncommon but also expensive)
That is only because car manufacturers mainly recommend only using "full synthetic engine oil", AND the CK-4 variety is only made in "15w 40 mineral engine oil" ,
whereas, the Top Dog global plus CJ4 is made in "both 10w 40 , and 15w 40 semi synthetic".
If your vehicle engine is able to use mineral engine oil as stated by the vehicle manufacturer and the cold-hot test numbers of 15w-40 align sufficiently, then CK-4 is the (better quality) superseding product global plus CJ4.

Commercial fleet vehicles , light passenger to heavy goods using the same oil type for all in the fleet, "have control modules to prevent exceeding RPM" , this limiter mechanism is not for speed, it is for engine protection!

WARNING
If you use an engine oil value of +10 on its hot test number the limitation is approximately only 2/3rds of the RPM band and the last 1/3 of RPM levels to the red line "must not ever (must never) be reached" or it could explode the oil pump! (apart engine fuel type specification of the oil use).

Similar terms with winter or severe cold, if the oil is more thick syrup number, only half the RPM band is allowed used for the first ten minutes (unless the "W" number is excessively watery and thin compared to the correct requirement of that engine model e.g 15w )!
e.g 4 cylinder with a "red line of 6000 RPM" ,
only 0 - 4000 (4500) RPM hot,
and cold start 0 - 3000 (3500) RPM for the beginning 10 minutes of engine on (E.g. oil is a 0w ).
(however , usually the "W" number ( larger) is more thin oil).
* NOTE: the number given for hot test and cold test("W") for an oil product are not the same scale! Though they seem similar neither can be used or compared to make a comparison of the other !!!!

WARNIING! about the following list!
If your vehicles or one of them "requires a cold test oil number W" below 10W there are only two or three in the list next that are manufactured as a 10w oil and will be the only choice you would/should use from the list!

Examples of multi-fleet oil and and multi engine fuel type oils:
Synfleet MX
Top Dog global plus CJ4
CK-4
Syn X 3000
Syn X 6000
Syn X 4000
(depends your exact price and what's your poison)
Unfortunately I cannot tell you which is best on any point for terms agreement in this site.
If you use "both diesel and petrol" cars or light trucks or 4wd, the mentioned oils are "a real world example" of keeping "one type of oil (small barrel large barrel)" for all vehicles (the same as commercial busines keeps a fleet) , and your engine will require management of RPM to operate safely.
WARNING 2
In the interest of safety and engine manufacturer common recommendation, half the list are "full synthetic", the most widely recommended, of which Syn-X 4000 is made to a viscous cold hot pair of 5w-30 , the majority of passenger 4 cylinder vehicles of diesel and petrol tolerances. Others in the list are ",semi synthetic" and/or mineral based!

If you must perform "the trick" based on cost , Top Dog global plus 10w-40 is the best for DIY for 4 cylinder passenger vehicles,
but remember the RPM rules of use STRICTLY !!!!!
FINAL WARNING: The above does not include any absolute oil and additive chemistry requirements, ALWAYS examine your engine manufacturers information and the oil manufacturer product information for use and chemistry specifics to make a sensible decision for the engines maintenance and operation!

Examples of two better versions of HUD projectors and some talk of pros cons
Vehicle HUD (GPS compass) pros and cons of the HUD (Head Up Display) machine.
*note: while often not manufactured and probably less choices if offered, a value difference of +/-5 in the hot or cold test number value required is considered "negligible" (allowable).

.
The pros and cons of HUD Head Up Display navigation units (the GPS compass) and a bit about how they operate.
Good ones bad ones.
the M22 is the one inside the vehicle, the C5 is the elongated large model.
The C5 requires running in OBD mode and it's GPS speed and compass will operate ok!
However, the C5 should be plugged into the vehicle OBD port connector under the dashboard!
Requires a double adapter cigarette lighter socket, and USB double adapter to insert to a socket !