Saturday, May 29, 2010

More difficulties predicting mode choice

As I mentioned in my last post, EngineerScotty and Jarrett Walker have been discussing various factors that motivate people's choice of one travel mode or another. Scotty and Jarrett are both interested in getting people to shift from cars to transit for similar reasons to the ones I list at the top of this blog. Scotty brought up Abraham Maslow's hierarchy of needs, and describes his reasoning as follows:
I think that actual research into what transit users want, as opposed to what planners, politicians, and amateur kibbitzers such as myself might think they want, is highly important.

Yes, definitely. But allow me to join the numerous commenters, as well as Scotty and Jarrett and Maslow themselves, in pointing out that there are tons of problems with using Maslow's hierarchy. Here are the ones that are the most salient for me:

1. Scotty frames the entire thing as what motivates people to use transit, without acknowledging that the issue is competition between transit and private auto use. Jarrett adopts that unquestioningly, as does Brad Aaron in his summary for

2. Jarrett tries to use the concept to argue why transit geeks just can't motivate the general public to go along with their grand schemes. But as commenter Adrian points out, "The disagreements you're alluding to are more about the appropriate time-scale for change, than they are about a pyramid of needs. The person waiting in the rain for a bus wants a better bus service right about now, but the warm and dry urbanist wants to create an urban form over the next few decades in which waiting for a bus in the rain will be less common."

3. Maslow himself acknowledges seven exceptions to the hierarchy, including number 5:
Another cause of reversal of the hierarchy is that when a need has been satisfied for a long time, this need may be underevaluated. People who have never experienced chronic hunger are apt to underestimate its effects and to look upon food as a rather unimportant thing. If they are dominated by a higher need, this higher need will seem to be the most important of all. It then becomes possible, and indeed does actually happen, that they may, for the sake of this higher need, put themselves into the position of being deprived in a more basic need.

However, I should point out that Scotty does not actually try to apply Maslow's original categories. He creates his own groups in terms of Maslow's concept of "pre-potency":
Human needs arrange themselves in hierarchies of pre-potency. That is to say, the appearance of one need usually rests on the prior satisfaction of another, more pre-potent need. Man is a perpetually wanting animal. Also no need or drive can be treated as if it were isolated or discrete; every drive is related to the state of satisfaction or dissatisfaction of other drives.

Scotty arranges the needs in eight categories of pre-potency, going from the bottom of the pyramid to the top: Access, safety and security, reliability, time and convenience, comfort, cost, amenities and societal acceptance. I think it's a good start, but I would prune it drastically, and keep in mind that this is forming the basis for whether people choose various modes or not:

1. Availability. What we readers of Jarrett's blog typically call "access." Can you get from here to there when you need/want to? Once you're there, can you get back, or continue on to your next destination? On the most basic level, nobody's going to choose a mode that won't take them where they need to go.

2. Value. This includes not only the monetary cost, but other costs as well. Door to door, how long does it take you to get there? How reliable is it? Is the risk of bodily harm within your tolerance? Can you get work done on the way, or at least get a little exercise? Scotty's distinction between incremental, access and system costs is valuable, but they all fall under this umbrella.

3. Amenities. These include everything tangible that makes the trip more or less pleasant but doesn't involve basic cost calculations, including comfort and fun. This is where most of the individual variation comes in: one person's value is often another's amenity.

4. Glamour. Everything non-tangible that affects mode choice: status markers, fantasies, the presence of attractive people (or conversely, their absence).

Two modes can compete on all these levels, but from what I've seen, most of the competition between transit/cycling/walking and private cars takes place on the level of availability and value. The vast majority of transit systems in this country are uncompetitive because they just don't go to most of the places where people want to go, when they want to do it.

The systems that are competitive on availability often lose on one of the value criteria, usually trip time. The Lincoln Tunnel XBL/toll/parking nexus gets thousands of suburban commuters to take buses by making them competitive on only two variables: trip time and monetary cost. And I'll point out it accomplishes this by allowing cars to stay slow (no tunnel expansion) and making them more expensive - not by anything it really does to the buses.

For the systems that are competitive on availability and value, they can win passengers through amenities and eventually glamour. This is where we are in New York. Most of the people who drive or take taxis on a weekday do so not because they're faster (they're not) or they go someplace transit doesn't (they don't), but because they offer a bit more space and privacy, and because they're more glamorous. In New York, transit needs to offer similar service levels and similar status endorsement in order to win over those who are either too good for the subway, or too old for that shit.


Barb Chamberlain said...

I commented on some of the issues with applying Maslow's hierarchy on Engineer Scotty's blog post you reference (

I won't repeat all of those thoughts here except to say that either your Value or your Glamour addresses a point I made there--that at least some people make a conscious choice about the impacts of their transportation and transit/biking/walking are all more attractive.

I recognize that's a limited segment of the audience but it's certainly a segment being targeted with plenty of ad dollars: all those "green" car ads that show an SUV out on the open road miles from anywhere and boast about their gas mileage.

"Drive and feel good about it" (i.e., no need to feel any guilt) is a definite theme. As you say, it's a competition--for hearts and minds.


EngineerScotty said...

I've another followup to this post, here.