Any new device that makes a sound the deer have not heard before will work till the deer get to know it. Once it becomes a normal sound when they are near the road then it is normal and will no longer have any effect on them.
The sound of your vehicle does not bother them alongside of the road because they hear it all the time. But when I drive deep into the woods where deer do not know the sound of an engine as an everyday sound, the scatter like cockroaches when the lights come on.
I am sure that the cheap air powered whistles worked for a while when they first came out, now that they are everywhere, it is just another normal sound that cars make. so a lot depends on just what sound this new device makes and is it different enough from the other noises that they are already used to.