Re:My 300 Mile Lyft Ride From Chicago to Bradford
by dredmorbius on Thursday July 25, 2019 @05:50AM
(#20523996)
You're at least attacking the weakest point of my argument, admitted in my comment you're replying to. Yes, the actual throughput is lower than the max, but the comparison still seems to favour rail.
Rayiner had tossed out the example of DC's Silver Line, though without bothering to state just what his argument was. I pulled Boston's BD project and ran with what numbers I could find (surprisigly scarce) to try to come up with some kind of metric for comparing total ridership capacity provided. Utility in daily trips served matters far more than cost-per-mile. And I hazily recollect that short-headway rail (DC Metro manages ... 6 minutes, by one statement, 26 trains/hr, or 2 minute headways (possibly bidirectional?) by another) does far better than a controlled-access highway.
My interest in doing unpaid, unreciprocated consulting for rayiner, esq., is rapidly diminishing, so I left off with some hazy numbers, but at least signalled that they are in fact hazy.
A USDoT source gives a maximum capacity of 2300 vph for a highway in good weather at 65mph.
And another sorce provided a 1.55 passengers/car loading factor, US average.
The WMATA source given earlier gives 26 trains/hr, 6 cars/train (actual in service, 8 cars possible), and 120 passengers/car (162% of seated load) as maximum capacity.
Multiplication gives 18,720 passengers/hr peak throughput, a bit over 12,000 passenger vehicles, or 5.25 lanes of highway capacity. I'd counted mileage to account for the difference in project lengths: Silver == 30 miles, Big Dig less than two. Point being that the spend of the two projects delivers very different total travel utility.
WMATA's Estimated average daily ridership, all lines, 2020: 1 million. Better than the Big Dig total.
As for rail and efficiency: unlike highways, rail (through traffic coordination and limiteds) can achieve both higher throughput and shorter trip times (balanced by less frequent service to a given destination) than highways. Trip times are overall more predictable. Safety and other factors, to both users and pedestrians, tends to be better than highways also.
Further factor are that rail service (which may or may not be bundled in project costs) includes rolling stock and maintenance facilities, as well as fuel/power, and maintenance, all provided by users of highways. Rolling stock lifetimes are generally measured in decades vs. years for autos.
Rayiner had tossed out the example of DC's Silver Line, though without bothering to state just what his argument was. I pulled Boston's BD project and ran with what numbers I could find (surprisigly scarce) to try to come up with some kind of metric for comparing total ridership capacity provided. Utility in daily trips served matters far more than cost-per-mile. And I hazily recollect that short-headway rail (DC Metro manages ... 6 minutes, by one statement, 26 trains/hr, or 2 minute headways (possibly bidirectional?) by another) does far better than a controlled-access highway.
My interest in doing unpaid, unreciprocated consulting for rayiner, esq., is rapidly diminishing, so I left off with some hazy numbers, but at least signalled that they are in fact hazy.
A USDoT source gives a maximum capacity of 2300 vph for a highway in good weather at 65mph.
https://ops.fhwa.dot.gov/publications/fhwahop13042/appd.htm
And another sorce provided a 1.55 passengers/car loading factor, US average.
The WMATA source given earlier gives 26 trains/hr, 6 cars/train (actual in service, 8 cars possible), and 120 passengers/car (162% of seated load) as maximum capacity.
Multiplication gives 18,720 passengers/hr peak throughput, a bit over 12,000 passenger vehicles, or 5.25 lanes of highway capacity. I'd counted mileage to account for the difference in project lengths: Silver == 30 miles, Big Dig less than two. Point being that the spend of the two projects delivers very different total travel utility.
WMATA's Estimated average daily ridership, all lines, 2020: 1 million. Better than the Big Dig total.
As for rail and efficiency: unlike highways, rail (through traffic coordination and limiteds) can achieve both higher throughput and shorter trip times (balanced by less frequent service to a given destination) than highways. Trip times are overall more predictable. Safety and other factors, to both users and pedestrians, tends to be better than highways also.
Further factor are that rail service (which may or may not be bundled in project costs) includes rolling stock and maintenance facilities, as well as fuel/power, and maintenance, all provided by users of highways. Rolling stock lifetimes are generally measured in decades vs. years for autos.