>>1064321There are a couple tricks to doing it right, like striping the lanes properly so that cars are not guided into each other, and having the proper geometry for left-turning traffic at the intersection. It's a little odd, admittedly, going by oncoming traffic on the left, but local traffic will get used to it.
The main perks are that they save space and store a lot of traffic, so they scale pretty well. Cloverleafs cannot scale.
The downsides have been mentioned, plus they kind of suck for >pedestrians.
