Most effective pedal position to jump start from still situation All other conditions (strenght, gear, etc.) being the same, what is the most efficient position of the pedals when starting from a still situation on a very short sprint (like crossing 10 meters wide road with a traffic light giving the start)?

I.e. I think that with the pedal on the highest point one can continuosly push for 180 degrees, but will start with a low torque, while with the pedal being horizontal one will start with the max torque but will then continue with reducing torque on just 90 degrees.
When you are starting, most force comes from your weight on the front pedal. The highest leverage is available when the pedal is in the 3 o'clock position. But starting there would waste the (potential) energy from going from the 12 o'clock (no leverage but maximal potential energy) to the 3 o'clock position. Hence, it makes a lot of sense starting with pedals in the 1 o'clock position with leverage increasing towards 3 o'clock and decreasing towards 6 o'clock.

A physics student could come up with an analysis for the best starting point by also taking into account the inertia of the system but I can't and have to leave it to may hand-waving arguments above.