Traffic is a great point. Every time someone chooses to take the subway or a bus over driving, traffic becomes slightly more tolerable for people in cars.
"Report: 98 Percent Of U.S. Commuters Favor Public Transportation For Others"
"Expanding mass transit isn't just a good idea, it's a necessity," Holland said. "My drive to work is unbelievable. I spend more than two hours stuck in 12 lanes of traffic. It's about time somebody did something to get some of these other cars off the road."
Except it won't because there's so much pent up demand for transit. A little extra capacity will be instantly used up by the people who were formerly inconveniencing themselves by leaving late/early.
Increasing throughput doesn't prevent you from being able to max out the system at peak usage times (rush hour), it just means that the rush hour traffic doesn't last as long.
