The highway center line and, by extension, the yellow line rule that we all must observe during our road races originated in Michigan. While there's some confusion as whether we should credit Edward Hines (1911) or Kenneth Sawyer (1917) as the first man to paint lines on the road, both helped to shape the roadway standards of Michigan and our nation.
The yellow line rule is just one of many rules in the rulebook designed to keep riders safe on the roadway. It's one of the easiest to violate accidentally and probably the most dangerous. It's also one of the harder ones to enforce for an official who is riding in the passenger seat of a follow vehicle. Sight lines are limited. Depth perception is challenging. And distractions with other aspects of the job make it difficult, which is why they rely on the collective eyeballs of the peloton to self-police itself.
Don't be that rider who takes advantage of this hard-to-enforce rule. Never cross the yellow line to advance your position. And always keep in mind the danger of oncoming traffic for yourself and your fellow competitors. Even if you don't cross the line, your riding may force others out into the opposing lane.
Making it to the finish safely should be your ultimate goal.