Road Speed Limiter and Warning



A basic option uses a pre-set limit for warning and/or preventing going at a specific speed.

To deactivate and change the setting requires a password. Activation would not require a password. Settings and operations can only be changed while stopped.

This might be used as a parental limit for the kids or as a valet mode where the maximum speed is limited.

A more advanced model would read the GPS location and identify the speed limit and provide a warning when the speed exceeds the map’s known speed limit by a set amount. For locations outside known roads (i.e. parking lots), it might limit speeds to 20 MPH.


Unknown if other vehicles have such an option. Using GPS positioning is not 100% reliable, especially when frontage roads run along a freeway or other close roadways.


Tesla offers two features – a speed limiter, and a notification when the speed exceeds the posted speed limit.  First introduced in the October 2014 time period.

Category: CY3XS Applies to:
     Created 2-Dec-2012


Unfortunately in Switzerland I often encounter wrong limits, the car shows 30, where it is 50, or even 50, where it is 120! So a locked speed limit (for the youngsters) would really be dangerous on certain roads, as the car would drive way too slow. But I like Ferrycraigs description.
    Created 12-Nov-2016
Most useful for me would be a GPS/camera cruise control. It would choose the more conservative speed. The operator could select speeds slightly above the limit. The camera would recognize speed limit signs (this because SPEED TRAPS can be created with signs in an area you'd not expect, and where the GPS hasn't been 'informed'.
    Created 1-Aug-2016
I appears that the biggest concerns people have about speed limiters, is that they believe, once set, it is not possible to exceed the limit set. This is NOT the case. In my Merc, the speed limiter can be set to any speed you want. It restricts you to that speed, in much the same way as Autopilot restricts you within lanes, provides resistance but can be overridden easily. The limiter is a voluntary thing. YOU select if you want to use it, YOU select the speed limit, and YOU select if you want to override it. I have only ever once wanted to override it, when I was approaching some traffic lights and I was worried they were going to change to red before I got there. Easy, foot down, zoom to lights, re-apply limiter once through the lights. On the other hand I have frequently smiled as I came round a corner, past someone with a mobile speed gun, in the knowledge the other drivers were getting the fines and the points and I wasn't, regardless of how fast I sped away from the lights.
    Created 30-Dec-2015
Since speed limits are known to navigation systems (I saw this on a TomTom), it would be really useful if the car alerted me when I am traveling a defined mph over the speed limit of the street I'm on.  This would be adjustable, just like the automatic lowering is adjustable.  I, for example, would ask the car to alert me when I'm going more than 10 miles per hour over the rated speed limit for the road I am on.
    Created 14-Sep-2014
Very good thoughts and comments! Beside the possibility to set a max speed limit I would personally very much like to see the possibility to reduce the power of the engine, so that the acceleration of the car is reduced. It doesn’t help much to reduce the top speed of the car if the acceleration still let the car go out of the hand of a less experienced driver.
    Created 6-Jul-2014
Speed warning with increasingly lud warnings as speed increases, and perhaps even notification to owner by SMS would probably limit most kids from playing too much, while not getting them in an accident for maxing out at 60 while passing a truck (like mentioned above).
    Created 20-Oct-2013
I would just want the speed warning function.  Many cars already have this.
    Created 28-Sep-2013
My Nokia Lumia 800 GPS based Navigation App is able to schow me the allowed speedlimit and warn me if I'm driving to fast. It's just a must have for car like this.
    Created 1-Sep-2013
Also seems to be a similar topic to these ideas:

  • selection of driving modes… i.e. winter, super sport, economy

  • option to have less power/acceleration

    • double tap accelerator pedal to temporarily disengage

    • or, alter mapping of pedal… i.e. have to push further to get to power-band

    Created 28-Jun-2013
i was also considering a feature like this - i was considering it a "governor" with multiple forms of aggressiveness:

  • Valet mode - drastically limit top speed and reduce acceleration curve

  • Child mode - limit top speed and acceleration (variable!)

  • Speed limit warning(s) - audible beep at set(variable) speed as compared to actual/posted speed limit  (utilizes NAV data)

  • Speed limit enforcement - does not allow vehicle to go X(variable - per user) mph over speed limit.  double tap accelerator to override for emergency/evasive situations

    Created 28-Jun-2013
The GPS-based warning (not limiting) is a standard feature in all sat nav systems I came across recently, including Navigon. Since Tesla uses Navigon for turn-by-turn navigation, the feature may actually be already present (for cars that have the Tech Package), or can be expected to be included soon.

I would like to suggest splitting this item into two, one for actually limiting the speed/acceleration, and a separate one for warning when exceeding speed limits. Although the items look similar, use cases and implementation are quite different.

Related item: Guest/Valet/Car Wash Modes
    Created 27-Mar-2013
This feature is in Teslas, just not accessible by the average user.  Test drives at the Tesla stores have cars with speed limits set at 80MPH so that test drives don't get out of control.  Found this out from the Tesla representative I was driving with.
    Created 12-Mar-2013