Finally, what about capacity? I already talked about seating/standing capacity of streetcars and buses, but how many of theirs spaces actually get used? There are several ways to look at this, not all of them well measured.

There’s the ratio of seats to occupants, the ratio of vehicle occupancy to its break even energy, the number of seats offered per hour, the number of passengers moved per hour, and the number of passengers moved by the system in a year. The last f these metrics is the easiest to measure with the data firm the National Transit database, because it takes an aggregate measure of all transit passengers in the year. We could get more detailed, not just in the transit line but in the number of passengers boarding and alighting at each station, but that is data that the transit agency may or many not collect, and may or may not make available to the public.

Its great when a transit agency releases origin/destination data.   This shows what routes and segments are the most crowded, and most deserving of better service. Conversely, it shows what stations are neglected by passers, to see where there are opportunities for station area development. The same transit vehicle serves the most lucrative and the most forsaken station, there is no reason a transit agency should not seek to enable transit area development wherever it can. Every piece of road is a development opportunity for traffic, after all. If a place is successful, DOTs just widen the road to it. If a place is unsuccessful but could be, DOTs build a road to it. There is no reason save maintenance and management that a transit agency should not think in the same way.

Of course, the data is the data, and the true meaning of transit capacity: passengers per hour, eludes us at a national level. At a national level, however, I can tell you how many passengers are carried per vehicle, simply by dividing passenger miles traveled by vehicle (revenue) miles traveled. A neat trick for over 800 bus transit agencies in 50 states.


Again, streetcar performs better than bus, but not significantly so. The sample sizes are much different, and some bus systems have incredibly high occupancy. It would be illuminating to see what sorts of systems are the best performing.

Of course, I can do any of these comparisons for light, commuter or heavy rail, and even have in the past.  Even better perspective would be comparing these with traffic, biking or walking.  I might do that, as soon as I figure out how to present it clearly.  The real asset of transit is in land use, but this is a poorly captured, documented or even proven asset.  Too many of the ways that we finance and build assume traffic as the primary mode.  Walking is merely the way to trot from building to parking space.  Transit and biking are such minorities as to be dismissed as insignificant.  But if they don’t have to be, and if we could benefit by enabling them, it serves us to disassemble the legal and practical fortress that binds America to traffic.

Next up, something completely different. I’m almost done noodling with 3,000 transit stations, but that’s not what I’m writing about next.