An official website of the United States government.
Here's how you know
The .gov means it's official.
Federal government websites always use a .gov or .mil domain. Before sharing sensitive information online, make sure you’re on a .gov or .mil site by inspecting your browser's address (or "location") bar.
This site is also protected by an SSL (Secure Sockets Layer) certificate that's been signed by the U.S. government. The https:// means all transmitted data is encrypted — in other words, any information or browsing history that you provide is transmitted securely.
Most drivers, when they see a merge sign, slow down too quickly and change lanes, causing a traffic backup. Continuing in each lane as long as possible reduces the speed difference between the two lanes, which helps keep traffic moving (zipper merge).