This circuit tries to follow the voltages based on this image: https://i.pinimg.com/originals/be/e3/3e/bee33e3900f485e036ab48387b4b2e54.jpg
I'm sinking the current from the LEDs via the open collector path of the comparator.
The comparators are not using a Schmitt trigger since the signals are not being used for digital logic, just the LEDs.
The LEDs are low-current ones, to avoid large current usage.
The zener diode is a 1N4740A from Vishay, with a test current of 25mA. Sadly I have no idea how to take the junction temperature into consideration. But I can't simulate it here either.
The quiescent current is 90uA (@9V).
The current while the car is stopped is 30mA (<12.5V).
The current while the car is running is 50mA (<14.7V).
I believe this can be more efficient if done with a low-power microcontroller with analog pins, or using an LDO instead of a zener (being the largest consumer @27mA).
Inspired by: http://everycircuit.com/circuit/5241387998773248
