Transportation notes

[rebeccmeister]

This university is home to the Texas Transportation Institute. I occasionally run into a graduate student who is housed there, because he is also a bicyclist. But whenever he's asked about the TTI, he's emphatic about the point that his job is to study cars and the things they do. This is typical of Texas, I find. Top-of-the-line, sophisticated research into driving. Not so much when it comes to other transit modes.

Anyway, the TTI just released a large study that's getting a fair amount of popular press, which incorporates a new index called the Planning Time Index - a measure of how much additional time one must budget if one *needs* to arrive at a certain location by a certain time. While it's good to see "reliability" factor in to driving trip plans, I sure wonder how PTI's scale for trips by foot, bicycle, or public transit.

I suspect the public transit option is pretty terrible in comparison, though that would depend on the city and country at hand. Not too long ago, my dad was telling me that most public transit trips take between 2 and 5 times as long as driving does, as a starting metric (though this may be outdated info). Just knowing this is useful for assessing (1) how long to expect transit to take, and (2) what constitutes a "good" transit network. My bus trips in Minneapolis tended to be closer to the 5x mark than the 2x mark, for instance. I also noticed that the trip from my parents' house to the airport was almost under that 2x mark.

Comments

travel time

[(Anonymous)]

The rule-of-thumb about transit travel times (between two and five times driving time) was repeated often by my transportation professors when I was in grad school, and I can attest to its subjective reliability in my experience in the years since then.

Regarding a PTI for public transit -- buses also get stuck in congestion, they run late, and sometimes don't show up at all, so a person does need to allocate time in addition to the time one would calculate from the published timetable. I suspect that a transit PTI would vary from city to city, from transit agency to transit agency, due to on-the-ground circumstances and how the agency is managed.

Also in my experience, I pretty much need to budget zero additional time for trips on foot or by bicycle -- there is simply no congestion affecting these ways of travel, though I do occasionally experience a delay due to a construction project, or a bridge opening.

Love,
Dad

Re: travel time

[rebeccmeister.livejournal.com]

I was partly thinking of the tight train schedules maintained by Japanese train operators, when considering PTI for public transit. But it would be interesting and useful to apply this to things like light rail and subway systems, too. I suppose I'd already assumed that bus PTIs would require the addition of considerably more time.

[sytharin.livejournal.com]

Since moving to Berkeley, I have gotten around almost exclusively through a combination of bicycle and BART--just because BART is so good for moving people long distances quickly, and the bicycle is so much more convenient and quick for short hops than figuring out the elaborate network of transit options around the bay. I generally assume that if I take BART into the city, I average the same speed as a car driver to major parts of town because of traffic across the bay bridge and difficulty finding parking anywhere, ever. BART comes frequently enough, and moves quickly enough, that it just doesn't make any sense to me why people would try to drive into the city.

In contrast, I've been kind of disappointed by the speed of Link the last few times I've visited Seattle. It never really gets to demonstrate the possibilities of light rail speeds when it has 30mph speed limits to share streets with cars. I hope that they are planning higher speed zones in the UW-Broadway-Downtown stretch.