 Are you for waiting until the last second to merge in traffic? Usually? Yeah. But there is the situation where it's actually the right thing to do. It's called a zipper merge, and it's a road design that encourages drivers to merge as their lane ends. Many states now recommend using zipper merges as a more efficient way to guide traffic during road work. It decreases traffic delays by up to 40% and reduces accidents. But shifting lanes ahead of the merge point to be polite puts all the cars in one lane, which means traffic slows down to a crawl. And even worse, those that are doing it right get me mugged by the other drivers who won't let them in. There are plenty of circumstances where you're in the wrong for merging at the last second, but not at zipper merges.