The Sierra Club asks, Does a mile in a car equal a mile on a train? Apparently not:
Pushkarev and Zupan in their pioneering 1980 study compared the six American regions with rail transit (New York-northeastern New Jersey, Chicago, Philadelphia, San Francisco, Boston and Cleveland) to other U.S. urban areas over 2 million population, concluding that for every p-m (STB: Passenger Mile) ridden on transit, four vehicle miles were not driven.
It’s an interesting read, if a bit technical.
Ah I have that book at my office. I’ll need to look through it again and pull stuff out. Thanks for the heads up.
So the point is that even if only 10% of trips are on transit, that’s as good as 40% of trips?
I’m confused.
The point is that for every new mile someone travels on transit across the lake, or from the U-district or Northgate to downtown, that will be four car miles removed from the same corridor.
Overall trip percentages are pretty useless. Remember, I-5 only has a few percent of daily trips as well. Looks tiny, but those “few” trips cause huge numbers of hours lost every year. The other trips, the 90%, are trips taken in off hours, on uncongested roads, walking down the street for lunch at work or hitting the grocery store. The commute trips are where this region’s congestion comes from, so that’s what we target with rail.
And in those corridors, I-5 or I-90, rail will be carrying thirty or forty percent of the trips.