So far, my experiments show this works with the NHW11. It may also work with the NHW20. However, it is a little "exciting" the first few times and somewhat risky if you are not practiced. PROBLEM Until the coolant reaches 70 C, the engine of the NHW11 runs regardless. If you are stopped at a light or stop sign due to traffic, the idling engine can make a significant impact on your mileage. However, turning off the car induces a second, more wasteful engine STOP/START cycle. SOLUTION NOTE: be sure to practice this with no other traffic around! Hold the foot brake with your left foot, hard! Shift into "R". Pulse the accelerator. --> engine stops Shift into "N". Use right foot to hold brake, normally When light changes, shift into "D", release brake, and drive off SYNOPSIS This works because the NHW11 turns off the engine when going in reverse. However, it appears you only have to be in "R" and hit the accelerator. It doesn't notice that the car is being held stationary by the power front disk brakes. So pulsing the accelerator causes it to shutdown the ICE. Then you slip into "N" to keep it from restarting the ICE. Now this process can be a little exciting and the steps have to be follow precisely. It is especially important that the left foot hold the brake HARD as backing into a car behind you will result in further delays. However, it seems to work. This may also work with the NHW20 but I do not have a test vehicle. Bob Wilson ps. Another method was described in this post.