Ever Wonder What Those Black Hoses on Indiana Roads Are For?. If you’ve driven on Indiana roads, you’ve probably crossed over those two black hoses stretched across the pavement. As your tires roll over them, you hear that unmistakable “thump, thump.” But have you ever stopped to wonder what they’re doing there? Were they left behind by a construction crew? Are they part of some sort of cable theft operation? Or maybe they’re being used for a speed trap? The answer to all those questions is no! These hoses are actually there for a very good reason.