It has to do with "brake horsepower". No. The only way two vehicles will stop in the same amount of time is if they are identical. If one is more massive, it will take longer. If the brakes were proportional based on mass and velocity, it would take a proportional amount of time for each to stop. In the real world, it does not scale up for a larger vehicle. Cars have a better brake horsepower to weight ratio than a truck, hence will stop quicker. The same applies to any vehicle. The only way to have equal stopping power is to have equal factors, mass, velocity and brake horsepower. Bear in mind also that the front brakes are generally larger than the back brakes. The reason is that a vehicle pitches forward, causing more weight on the front than the back. The shift in downward force means more brake horsepower is exerted by the front wheels, so they have to make the brakes larger to handle the added loading. My VW Microbus is an example, disk brakes in front, drum brakes in back.