Without white and yellow lines on streets and roads, we wouldn't know where the lanes are, or where to turn or stop or walk, etc. Car accidents would be much more frequent, many with fatalities.
A specialized sector of the construction industry paints lane markings on roads. One company in Michigan, PK Contracting, estimates that one worker paints about 400,000 ft (122,000 m) of lines every day. Over the 6-month construction season, the company stripes and re-stripes about 50,000 mi (80,500 km) of roads. Put those markings end-to-end and you could cross America 16 times.
Those figures don't include crosswalks, turn arrows, stop lines and all the other markings you see. For straight lines stretched down a road, the workers use a special painting truck that paints lines as it drives. But they can't use the painting trucks in tight spaces, or for curves and arrows. So every one of those lines and shapes is painted by hand using big stencils and either spray paint or rollers.
It requires precision to create straight lines, a cross-hatched zone or a set of arrows with multiple stencils. The painters need to be very skilled workers. You can see them action at the "Continue reading" link below.