Transportation engineers have long been painters, although the markings they have applied in white and yellow are not something anyone has ever recognized as artwork. Of course, they never intended for their functional markings to be a visual art (although their engineering work can be as much art as science at times). I find it interesting to note the pallet they use has been expanding in recent years, and our cities are gaining a little more colorful accent as a result. In some cases, transportation agencies are even using paint to create public art in places that have traditionally been mundane or outright unsightly.
Here's a quick rundown of the color pallet used for functional markings, a note about incorporating art to mitigate the unattractive spaces sometimes created by transportation, and some discussion of the limitations of paint.