>>1278708Not this way. Tidal flow operation can be easily done with at least triple carriageway, ie the odd central one reversible. (like a local-express system)
This asymmetric configuration is commonly found in road expansions. Say you have a tunneled or elevated four-lane two-way in two two-lane carriageways (tubes or viaducts). You can add two more two-lane carriageway for eight-lane two-way, or one three-lane tube for seven-lane two-way with four-lane in the peak direction.
Since the a.m rush hour is usually more predominant and concentrated, it could be wise to permantly make the inbound direction have more lanes.
