I recently wrote a new PHP router (Piko router) that stick out from the others by its implementation.
Unlike popular PHP routers, Piko router doesn't solve the problem of route matching using regular expressions. Instead of that, it uses a radix trie structure to store routes definitions and a search algorithm to retrieve them against a given path. This approach is very efficient because the search consist just to traverse a prefix tree.
Piko router was initially designed to be used in the Piko framework (another project I made) but it can be embedded as a standalone dependency in third party application via composer.