As of November, the old bridge will be for public transport plus taxi's and private hire vehicles.
Motorcycles up to a certain CC will be allowed on the old bridge as well as pedestrians and cyclists in the current format - although I think one side will be cyclists and the other pedestrians.
New bridge will be for the general public and commercial vehicles. This will become 70mph as of November.
If the old bridge needs to close because of high winds, the new bridge will end up three lanes each way, with the hard shoulder used for public transport.
The big issue for me, is that the problem often isn't getting over the bridge, its getting to it. Queensferry Road, Telford Road, Blackhall, etc will still be choked with traffic and like getting to the new M8, nothing will change in that respect.
Anyway, I still think we should have built a tunnel