> tree-lined streets encourage slower driving without any speed limit signs Somewhere near me (south UK) has a dual carriageway that approaches a roundabout. T

> tree-lined streets encourage slower driving without any speed limit signs Somewhere near me (south UK) has a dual carriageway that approaches a roundabout. There is a fence on the side of the road as you approach the roundabout, so that you cannot see what traffic on the adjacent road is doing, forcing you to slow down on the approach, rather than maintaining a higher speed when it appears you might get away with it. Seems to work quite well.