in my personal experience (with both transit and non-transit friendly locales): within NYC: bikes are the absolute fastest for short distances, the subway is c

in my personal experience (with both transit and non-transit friendly locales): within NYC: bikes are the absolute fastest for short distances, the subway is comparable but generally fastest overall once things stretch out a bit, cars get hampered by "conditions" including traffic and parking; so they're ok if you hire a car late at night, but otherwise pretty slow and likely to get stuck in traffic. in the dense burbs (silicon valley, southern ca, hillsdale, long island): bikes are a mix but generally slower, cars are the fastest, transit takes 2-3x as much time, except during congestion where grade separated modalities often come in about on par with car travel time. in the rural burbs: cars win. transit takes 2-3x as much time. grade separation is rare, schedules are light and traffic is rarely an issue. i would want to see how these averages are being calculated. i'm guessing they're probably just doing a flat average over all zipcodes. this seems wrong to me, instead if you want to come up with a summary stat (which i think is probably a bad idea, as there are so many different types of cities with different behaviors for this sort of comparison) you'd probably want to weight by population. to say that the national average is 2-3x probably overweights all the rural transit systems where this is true.