White paint is cheaper and markets well. Never forget how conservative most purchasers are. It's a shame really because it does mean that carvan sites are an eyesore due to the way the weight vans sick out like a sore thumb for miles.
White reflects the sun and keeps the temperature down inside motor homes without using air-con most RV have air_con fuel is cheaper in the states – most caravans and motorhomes are used during the summer months.
No, this is a common misconception. Being white may increase the time the van takes to reach it's top temperature but not what that top temperature is. Consider a if you put a black brick and a white brick into an oven; they will both reach the same temperature. Interestingly the black brick will cool quicker in theory as it will radiate quicker but convection and conduction will happen at the same rate as the white brick.