I had a similar experience several years ago…it was after dark, say 11:30pm and there was a group of l0-12 raccoons running down the middle of 51st SW making strange shrieking noises.. I knew I didn’t imagine it, but I have never seen anything like it since! To describe it to anyone else seems so crazy, but I witnessed it as you did.
They did look like they were running ‘from’ something, but nothing appeared to be chasing them.