From what I can see, it's not about higher throughput (which stays the same)
It's about reducing queue length (you use 2 lanes instead of one, so the queue length is halved) and smaller speed differences between cars on adjacent lanes.
Anyway, I'm not talking about cases where one lane is closed (which is what WSDOT and the Minesotta doc talk about). I'm talking about cases where there is a one lane offroad from the highway, with a queue of cars waiting to take it. Plenty of people will skip the entire queue and try to merge right at the end, blocking half of their own lane while waiting for a gap in the queue.
It's about reducing queue length (you use 2 lanes instead of one, so the queue length is halved) and smaller speed differences between cars on adjacent lanes.
I can't find a good WSDOT source, but here's Minesotta: https://www.dot.state.mn.us/trafficeng/workzone/doc/When-lat...
Anyway, I'm not talking about cases where one lane is closed (which is what WSDOT and the Minesotta doc talk about). I'm talking about cases where there is a one lane offroad from the highway, with a queue of cars waiting to take it. Plenty of people will skip the entire queue and try to merge right at the end, blocking half of their own lane while waiting for a gap in the queue.