I once worked with the manic guy who would paint the lines on the streets of my small hometown. Our work was decidedly one-dimensional, despite his art degree, and our small painting rig was not meant for big striping jobs, especially curvy roads. To create a radius, we'd set up guide strings and make a smooth arc. It didn't always work out, and my friends would rib me mercilessly after trying to follow the crazy angular path we'd sprayed.
A recent study by North Carolina State University has shown that the stripes dividing our nation's roadways are brighter when they are applied in the same direction that traffic is flowing. In many cases, the twin center lines dividing opposing lanes are painted at the same time, making them more visible in one direction than the other. The issue seems to center around the glass beads that are mixed in with the paint. These reflective beads are most effective when properly oriented.