Traffic lights chop up traffic flow, creating windows of opportunity for turns and crossings at minor intersections downstream. Roundabouts on the other hand cr

Traffic lights chop up traffic flow, creating windows of opportunity for turns and crossings at minor intersections downstream. Roundabouts on the other hand create bottlenecks of relatively constant throughput, smoothing out any pulsation in traffic density (e.g. from upstream traffic lights), which makes minor downstream intersections much more difficult. Determining the best option for a given case is more an at than a matter of simple preferences.