Silver is a popular colour for rental vehicles. Cars that are silver retain their value better than any other colour, reselling for around 10% more than white cars; this superior resale value has caused many UK police agencies to replace their standard white patrol cars with silver models. Studies show that white cars are safer, getting in 12% fewer collisions than black cars, although some studies show yellow cars as being slightly safer than white. This is a major reason why
school buses are yellow in much of the world. The safety difference is because lighter coloured cars are easier for other drivers to see, especially at night. However, other factors, such as driver behaviour and weather, are significantly more important to vehicle safety. == Historical trends ==