What is the primary factor that causes the total stopping distance of a fully loaded 40-tonne truck to be significantly longer than a passenger car?

1. Enormous kinetic energy (E = 1/2 m v^2) requiring substantially more braking friction energy, combined with pneumatic brake system response lag (0.2–0.4 seconds)
2. Truck engines have smaller displacement
3. Truck drivers have slower biological reflexes
4. Pneumatic brakes are weaker than bicycle brakes