Modal differences in travel time

[cimmee]

Disparities in travel times between car and transit: Spatiotemporal patterns in cities - Scientific Reports

Cities worldwide are pursuing policies to reduce car use and prioritise public transit (PT) as a means to tackle congestion, air pollution, and greenhouse gas emissions. The increase of PT ridership is constrained by many aspects; among them, travel time and the built environment are considered...

www.nature.com

"Cities worldwide are pursuing policies to reduce car use and prioritize public transit (PT) as a means to tackle congestion, air pollution, and greenhouse gas emissions. The increase of PT ridership is constrained by many aspects; among them, travel time and the built environment are considered the most critical factors in the choice of travel mode. We propose a data fusion framework including real-time traffic data, transit data, and travel demand estimated using Twitter data to compare the travel time by car and PT in four cities (São Paulo, Brazil; Stockholm, Sweden; Sydney, Australia; and Amsterdam, the Netherlands) at high spatial and temporal resolutions. "

I've been looking at efficiency studies (car v train) and have always found them lacking in that they are one dimensional. In other words, solely focusing on energy consumption ignores an important variable (time). Time has a cost as does energy. Ignoring time as a cost factor when determining efficiency invalidates whatever "study" is presented.

I would posit that rail is much less efficient (in the USA) when viewed in totality.

 

[Trollopian]

I've been looking at efficiency studies (car v train) and have always found them lacking in that they are one dimensional. In other words, solely focusing on energy consumption ignores an important variable (time). Time has a cost as does energy. Ignoring time as a cost factor when determining efficiency invalidates whatever "study" is presented.

Economist here, and I completely agree that time has a cost (an "opportunity cost" in econspeak). But even then the analysis isn't clear-cut. A merit of train travel and public transit is that the traveler can do other things. Productive things or leisure things, whichever. People regularly work on commuter rail or Acela. On Washington's Metro I've seen lawyers reviewing briefs and civil servants marking up drafts and fellow economists eyeing reams of very dull-looking statistics. Admittedly, not so much on (e.g.) the Zephyr. But driving takes, or should take, constant attention and mental energy. That's a time drain.

In very dense cities like New York and London that are hives of high-paid and modestly-paid employees, a train commute will typically beat the same trip by auto.

(That actually is a major reason I worry about self-driving cars. They will upheave the economics of driving and of urban sprawl, once a car commute no longer requires a driver.)

 

[JamesWhitcombRiley]

I wish self-driving cars only self-drove on highways with guide lines, as the original plan was.

OK, back to the original post.

A private jet is pretty time-efficient. Yeah I think as a practical matter, all of us have chosen driving over a train depending on circumstances. It's been fascinating reading the posts about India. That's a middle income country, but in truly developing places like Lagos people try to do as much business as possible by text or video, due to unbelievable road traffic. Before the smart phone even, a guy from there was telling me about 7 second voice billing, and message rates. Meanwhile we do have this massive investment in highways, so it can be pretty efficient. But say, Norfolk VA to Alexandria/Washington, people take the train because of the massive clouds of uncertainty and stress and cost trying to drive it (about 4 hours) during business or weekend hours, really any time the sun is up or has been recently, or will be soon. Might apply especially to people who do the trip often. Ridership is way up, anyway.

Also, the environment.

Another thing about time, the quickest the railroads will get freight from Norfolk to a place like Washington or Hagerstown is one day. For bulk, a train carries 4 times a truck. A barge on a tow on the Mississippi carries 10 times a train car. A barge is really slow, but cheap. The Port of Virginia runs a barge service between Richmond and Norfolk/Newport News, perhaps not wildly popular. Tacoma to Alaska, of course, it's the major mode. Not that different than what you're saying perhaps.

 

[MARC Rider]

May commute from Baltimore to Washington back when I worked was about 2 hours, including a drive to the station, an hour ride on MARC, the Metro from Union Station and a short walk. A couple of times I drove down for various reasons, and the drive time was about an hour and a half. I still continued to take the longer public transit commute because, though faster, driving was much more stressful. If you weren't stuck in stop and go traffic, you were in bumper to bumper traffic going 70 mph. With big trucks and cars changing lanes in fron of you without warning. In the dark.

Maybe if I had a nice plush limousine with a chauffeur driving it might be different.

Also, the 40 mile trip by car had operating expenses of about 60 cents per mile or $24. Plus parking in downtown DC is not cheap. A MARC one way ticket is $8, though most regular commuters buy monthly and weekly passes that come out to less per ride. I hardly paid anything because I had a transit subsidy from my employer.

 

[slasher-fun]

I've been looking at efficiency studies (car v train) and have always found them lacking in that they are one dimensional. In other words, solely focusing on energy consumption ignores an important variable (time). Time has a cost as does energy. Ignoring time as a cost factor when determining efficiency invalidates whatever "study" is presented.

Except that for commuting, time is a fixed factor, not variable: people will on average live a certain time away from work (usually ~30 min), not a certain distance away.
That's why widening highways to solve congestion never works: what used to be 30 min away turns into 20 min away, so people are more willing to make that was-30-now-20-min trip, so there's more traffic, so... congestion increases, and it quickly goes back to still-30-min-away.

Meanwhile we do have this massive investment in highways, so it can be pretty efficient.

Highways cannot be efficient. Or actually no: highways with buses are efficient, highways with cars are not.

Let's take for example a perfect single lane 30 mph street. No intersection, no traffic lights, no pedestrian crossing, perfect drivers.
On that street, you have capacity for about either:
- 1500 cars per hour. There are usually 1.5 occupant per car, so that's 2250 people per hour, but assuming all cars have 5 seats, that could be 7500 people per hour if they're fully used
- 1200 buses per hour. Not sure about the average occupancy, but peak occupancy means 125 000 people per hour. Yup, as many as if you had 17 lanes for cars
- 20 000 pedestrians per hour (assuming here that's a one-way pedestrian street with perfect pedestrians of course)

If you want to have as many people as possible travelling as fast as possible, you make it so that cars are only used as a last resort solution, when all other modes of transportation aren't a plausible solution for that very trip you're trying to make.
But if you want to have as many people as possible travelling by car, you'll only have a small number of people travelling vs what you could have had with more efficient modes of transportation.