my experience with hypermiling is has been very bad.
I think it can cause an accident if a person goes to the very extreme....
but here are some tips....
- less load on the car
- car inflated at 32 psi (cold inflation)
- air filters need to be clean
- use lower rpms, and always be on the highest gear possible....
- constant speed and maintain momentum of car always avoiding to brake
extreme
- turning car into neutral gear...
- ditching spare tire
- switching of engine while driving....