The gain isn't "modest". At a cloverleaf, the weaving between people entering a highway from one leaf and people trying to get onto the next leaf is an utter d

The gain isn't "modest". At a cloverleaf, the weaving between people entering a highway from one leaf and people trying to get onto the next leaf is an utter destroyer of traffic flow, especially when you add in some human behavior, where some people are assholes and won't let people merge in front of them, even when they're trying to merge to the other lane themselves.