As an example, the maximum capacity of Highway 401 east of 404, which is in most sections 14 lanes, 7 lanes per direction (assuming 2000 cars per hour per lane) is 14000 cars/direction/hour, and west of Morningside it is heavily congested westbound in morning rush hour. The maximum capacity of LRT with multiple unit trains (assume crush load capacity of 500/vehicle) running 5 minute headways is 6000 people/direction/hour, also it eliminates any possibility of widening Sheppard to 6 lanes for a possible loss of 2000 cars/hour/direction. My assumption is that signal priority becomes ineffective at headways <5 minutes causing frequent stopping at red lights and severe streetcar bunching, so headway is assumed to be limited to 5 minutes, and that running full subway-length trains is difficult because they would block intersections. The Spadina streetcar runs shorter headways, but suffers from very slow speeds and severe bunching resulting in bad service. In comparison a subway would run longer trains (1000 person crush load capacity) every 2 minutes, so it would have a maximum capacity of 30000 people/direction/hour, double that of Hwy 401.
Just an fyi, the maximum capacity of any vehicle lane is 1800 vph, not 2000. It doesn't change what you're trying to say, but I just thought I'd let you know for future reference. If you do the math on 1800, it works out to being 1 car every 2 seconds, which is the accepted safe travelling distance, which most people follow (some don't, but some also leave more than 2 seconds space, so it balances out).
Also, can we please get over this myth that building a subway along Sheppard is going to somehow relieve the 401? They're serving two different patterns. Most of the people on the 401 eastbound at McCowan in the AM peak got on it outside of the City of Toronto. Very few, if any, of those people are going to get off the highway and take a 50 min subway ride downtown. The only people that a Sheppard subway are going to benefit are those who would otherwise be getting on the 401 at Victoria Park, Warden, Kennedy, or McCowan (and to a much lesser extent those further east in Scarborough who would bus to the subway).
The only true competition to the 401 would be GO Transit. I could see a lot more people getting off the 401 at McCowan and then driving to the Agincourt GO station (assuming ample parking there), and taking that downtown, because there would be a significant time savings involved. Of course, many of those people would probably be equally served by increased GO service along the Lakeshore East lines in Pickering and points east of there, so that is sort of moot.
My point is this: If you want to relieve highway congestion, look at the only form of rapid transit than even comes close to approaching highway speeds: regional express rail. Pour the money into that, and you'll see highway congestion decrease. But this notion that the Sheppard Subway will affect the 401 is pretty ridiculous. The effect will be negligible, at best.
