A few people asked me about syncing traffic lights and stuff in 0.4 before everyone started freaking out about custom skins (which I have to thank maxo for implementing since it would've taken me forever to get around to that). Since I was working on some other major changes to VC:MP, I decided to sneak in a quick fix to sync the game timer between the client and the server. This allows traffic lights, waves, particle effects and some other very minor stuff to be synchronized between clients.
Quick video I recorded of it:
Sorry for the absolute lack of editing but I didn't really have time to do anything comprehensive for a one-off video like this.
Because of the netcode changes from this, it may not be able to be released until the next major game update, but I don't anticipate that taking too long, though time estimates have generally always been wrong so I don't want to really give one.