Speed limiter/Governer in a newer car?
 

With the new job too far away for the Leaf, the Golf with a busted transmission and the Bug not wanting to get started up without leaking like the Exxon Valdez I have been contemplating selling all and getting a newer car.

However, with the amount of miles I'm planning on driving (about 24,000 per year) I feel that it's going to be more important than ever to reduce both fuel consumption and wear and tear. Obviously one way to do that is to drive slower. A block behind the accelerator pedal seems like a good start. But what about top speed? Note that I may not be the only one driving this car, yet I'm the one that's going to be paying for it. And even when I do drive there's always that temptation to go a little faster. Let's say I get a newer Toyota or Mazda and limit top speed to 55mph. Is there anything that would work correctly with modern electronics? Any ideas as to what I could fabricate myself?

Open to all ideas and criticism.

In modern vehicles what's required is adding a speed-limiting program to the ECM. Even though it doesn't seem so common to set such a strict limit there in the U.S., in Europe some vans have this feature available straight from the factory.

Lots of the cars from the major rental car fleets are governed to just over 80 mph. I assume it's with a simple ecm flash that put back to stock when resold. Now there have always been ways around such things. One trick that used to work on Chrysler products was to hold the key to "start" while driving and it seemed to forget it had a limiter. Almost all cars have some limiter from the factory, it's just a matter of program where it is set.

What about an alarm? Found this with a quick Google search.
Avoid Speeding Tickets with Rx4Speeding Car Speeding Alarm
The one with the switched output could be used to cut power to the injectors.

DIY reverse cruise control would be possible, but probably a lot more work than just keeping an eye on your speed or using cruise control.

Anyways, this is how it could work. You'll need an arduino or other programmable microcontroller to read the vehicle speed sensor, and intercept the gas pedal position sensor. Allow a direct pass through signal for the pedal position sensor for everything until speed exceeds X, then start modifying the output signal of the gas pedal position sensor to limit max speed.

Sounds tough but I like the idea. The same device could also limit max power.

Cripple rooster is right about modern european cars. When i was delivering hire vans a few years back mercedes sprinters had a variable speed limiter. Hire company had these set to 65 mph. I worked out how to raise limit. Peugeot also have a variable speed limiter which you can set yourself. Must be easy if you have the knowledge to reto fit. They all worked of speedo reading. So if going up hill you could maintain speed and not be rev limited. Would suggest an ecu specialist or if buying new ask dealer if one could be factory fitted.

I would be careful about limiting the top speed too low, if you get in a situation where you need a few more ponies to merge, etc. It may not be available.

WILLPOWER!!!

I recently drove my father inlaws honda civic.

It has cruise control AND a speed limiter. In speed limiter mode It will not let you pass the aet limit (unless you go full throttle).

My 95 camry had cruise control but mb 1999 e200 and 2003 ml350 had the speed limiter. What sucked on the ml was that it did not even disengage at full throttle. Major design flaw in my opinion. One would have to hunt for the lever.

That would be more of a problem if the only input for the speed limiter was engine RPM. Well, even though a lower top speed may eventually become a problem to merge with the traffic in some expressways, depending on how the speed limiter is tuned would still enable the cut-off limit to vary according to the gear selected (a similar setup had been used in some 50cc motorcycles in my country in order to enable them to be registered as mopeds).