Idea: cross-border EU motorway vignette

It'd be a great reduction of citizen hassle when crossing borders if there was an EU motorway agency where you'd pay for a single vignette that was valid for the entire EU instead of having country-by-country motorway tolls, which are particularly annoying in small countries. It'd also make sense to plan motorways across the continent and standardise road signage and rules so you don't have to be surprised when you cross borders.