As for roundabouts, having learned to drive in Australia where there's an abundance of them, they work fine when you're on the street going with the flow of traffic. If you're on the side street, forget about it.
Drivers always complain about the timing of traffic lights. It looks like a no brainer to set the lights for your car, but the traffic engineer has to also accommodate the traffic in the opposing direction as well and cannot violate the laws of physics.