Also, very often it doesn't reduce flow even for cars. There are tons of times when you remove lanes and it improves are keeps flow constant.

4 lane roads are the worst, you can get the same effect with a 2 lane with a turn.

It really depends on how many intersection you have, having a single lane that only branches to 2 in front of an intersection can be more efficient, then constantly 2 lanes.

The US style of many lanes, many intersections, is horrible from safety and a flow perspective.