Roundabouts are OK, but they still have the problem of directional priority, which at peak times can produce unbroken streams of traffic on the main flow and a "need" for lights (to interrupt those streams and enable others to enter). It also means people who arrived earlier have to wait for people who arrive later. Why should they? Could no priority, aka filter in turn (FiT), aka the all-way yield, be the best of all worlds?