On the A/T maxima is this supposed to be pressed in stop and go driving? Should there be no overdrive?

 

Just leave overdrive on all the time. Especially where you live.

It's used to keep it from going into OD when towing or going up long steep mountains. In those conditions the RPMs can drop too low for the load or it can start "hunting" where it bounces in and out of OD.

Under normal conditions it will go in and out of OD when it's supposed to.

 

I would just add:
When in OD, there is very little (if any) engine braking.
When out of OD, the engine braking is reasonably effective.

 

Or traveling with overweight people?
OK I see.