[fusion210]

Originally Posted by Vman455

We can simplify this problem a bit and attach some actual numbers using the Work-Kinetic Energy Theorem to get a general idea if it's worth rolling through or not. Assuming a weight of 1850 kg (the lightest trim of the 2006 Highlander Hybrid, yours may actually be heavier), a speed limit of 25 mph (11.1 m/s), and a difference of 0 mph (full stop) versus 1 mph (0.444 m/s rolling through):

Work (W) = Kf - Ki
K = (1/2)mv^2
Kf = (1/2)(1850 kg)(11.1 m/s)^2 = 113969.25 J = 114 kJ
Ki,rolling = (1/2)(1850 kg)(0.444 m/s)^2 = 182.3508 J = 0.182 kJ
Ki,stop = (1/2)(1850)(0 m/s)^2 = 0 kJ

Wrolling = 114 kJ - 0.182 kJ = 113.818 kJ = 114 kJ
Wstop = 114 kJ - 0 kJ = 114 kJ

So you can see, the difference is within rounding error to 3 significant figures. However, that 0.182 kJ does equal 0.05056 Wh, out of 33.1 kWh in one gallon of gasoline--or 0.0000015% of a gallon. You would need to roll through approximately 654,725 stop signs at 1 mph to save one gallon of gas, and that's assuming 100% conversion efficiency.

There are much easier, legal ways to save one gallon.

That's pretty amazing as my answer was going to be full stop with traffic or not great visibility, but mostly 1-2 mph.