TheTigerMaster
Superstar
IMHO Corridor D edges out B slightly because it will (mostly) negate the need for some riders to transfer from the DRL to join Line 1 peak flows. It's not a big deal if someone in the AM transfers from DRL to Line 1 NB to get to Queen, but the reverse (Queen->King) will have a negative impact on SB capacity. Don't underestimate riders' willingness to transfer for just one stop!
I have to disagree with this. Dundas Station is by far the most used station on Line 1, south of Bloor. The biggest trip generator here is presumably the Eaton Centre and Ryerson. The benefit of Corridor B (Queen Street) over D is that it will provide direct access to the Eaton Centre and City hall, while putting riders only a few minutes walk away from Dundas Street and the Financial District. Option B (Queen) is the best option for serving these two major destinations.
With Corridor D, you'll be serving the Financial District, at the cost of failing to serve the major destinations at Dundas.