That stated emissions figure for PTWs is 3% off my car. That's appalling.
Emissions have nothing to do with congestion which is what the bus lanes were put in for, and a car in a traffic jam is going to emit far higher levels mile for mile than a motorcycle which stays moving.
You have already indicated that you commute by car (single occupant), so your journeys are fairly inefficient considering you live in such a densely populated city when compared to motorcycle commuting.