[aerohead]

I believe that the 'process' involves reflecting as much of the visible and ultraviolet back towards space, before it ever has an opportunity to transform into long-wave infrared after is strikes the surface.
Flat-white is best for that. Not any 'glossy' surface.
And even with the best albedo, given enough 'time' in the sun, the car will reach the same temp. as a 'black' car. It just takes longer.
And something not mentioned is 'latent' load.
Relative humidity is often the 'reason' why air conditioning is used. It's not just the dry-bulb temperature.
Around 'local' dewpoint temperature, air is 'saturated' with water vapor. It's impossible for perspiration on your body to 'evaporate', which, otherwise could make one comfortable.
Where I live, 80-degrees can feel like 104! And it can kill you.
I agree that reducing the solar load can reduce energy consumption, but it must be taken within the context of human factors and human physiology.
'Cooling', without dehumidification only 'INCREASES' relative humidity, and the Heat-Index. It's why we have 'refrigerated-air'.