Simple way to save auto engine fuel
When you see a signal light half a block ahead go to yellow, ease off on the throttle and let the vehicle more or less coast to the light ... you'll see several cars slip past you at throttle in the other lane ... and when they get near the light ... the brake lights go on.
Jack-rabbit starts from signal lights are fuel wasters, as is rapid acceleration. Accelerate at a gentle rate.
Drive as though there's a raw egg between your foot and the accelerator pedal.
And smile - you're usng fewer litres of gasoline/diesel.