I'd think on a very frequent peak-hours route, that AODA rules would be fulfilled by having 50% of the vehicles accessible.
Though I fully expect the CLRVs to be fully retired before 2024 ... and the ALRVs even earlier.
The last I heard, the system has to be ODA standard 100% by 2018. MTO wanted the system to be done by 2015, but allow the extra 3 years extension due to the various issues.
This meant that TTC still can run the current fleet along with the new fleet as specials to off set over crowding at peak time since they didn't do the 1:1 as I said they should since 2005 for replacement. They can be used for special events as well being used for tours. Still can do what was being done on the 509 during the summer with the PCC on other routes.
If the plan stays in place as plan, ALRV's gone by 2015 with the bulk of CLRV's by 2020 if not all of them. Depending on what TTC plans for the fleet to be retain as historical fleet, they will be retire in name only for daily service and still be on the roll like the Witt and PCC's. To be retire 100% would mean they are on display or scrap for TTC system and not using the system for special events under my books.