In previous posts, I have outlined four clusters of factors influencing mode choices:
I also observed that there were at least three types of mode choices: per-trip, long-term decision and long-term investment. I've decided to rename them, as follows:
One reason that there's so much confusion around motivations for mode choice is that the four factors affect the types of decisions in different ways.
Availability affects all three decision types, but it's a slightly different type of availability. If I live in a small city with one of those three-loop bus systems, and Loop A is going downtown at about the time that I'm going downtown, and I know that I'll be coming back before the service ends at 6:30 PM, I may, for one Trip, say, "Hey, why not? Let's take Loop A downtown." But I wouldn't make a Habit of taking the bus downtown if there was a possibility that I'd have to stay late, or get home in less than an hour. I definitely wouldn't make an Investment in a home or a job that depended on Loop A - unless I had a bike or a car to serve as backup.
Value is important for Habits. It's not that important with Trips, because a single trip within a city doesn't cost that much. If I'm a teenager bagging groceries at a supermarket, it's probably not cost-effective for me to take taxis everywhere, but I may splurge for a cab on a hot date. Value should probably be the predominant factor in Investments, but it isn't always.
Amenities are not very important for single Trips. If you're running late or it's raining, you may be willing to stand on a bus. They're much more important for Habits and Investments, because these are things that you're going to live with for a long time.
Glamour definitely counts for single Trips; they can be a way to try out new modes and see if they live up to the fantasy. It's not so important for Habits, because it fades so quickly. To illustrate this, as I commented on Jarrett's followup post, think about the Hudson Line. It's exciting to ride along the beautiful river and look up at the Palisades, but I'll bet that most people on the 7:56 out of Croton aren't even looking at it. Fun gets real old after a couple weeks.
Where glamour makes the most difference, strikingly, is in Investments. That's because glamour is escapist fantasy, essentially, as Virginia Postrel observes, "life would be perfect if..." Life would be perfect if I got driven in a limo/drove a Miata/rode a fixie/rode the streetcar/walked to work. If I lived in a cabin in the woods/in a raised ranch with a backyard in Nyack/in a mansion in Scarsdale/in a condo on Park Avenue/in a loft in Williamsburg. If I worked on the road/in a modern office park in Lake Success/in a high-rise in Midtown/in a loft in Williamsburg/as a bike messenger. If my kids went to Bronxville High/Hunter High/the Dalton School.
All of these fantasies can override our calculations of Value. They can mess with Availability, but we come down to earth pretty quickly if that happens. They can mess with our Amenities, but that doesn't really matter. Where glamour really messes things up is when we wind up buying cars when we can get around fine without them, or when we buy a house in the suburbs when we were doing pretty good in that apartment in the city, or when we take that flashy job that requires the two-hour commute, or when we put our kids in the school that isn't on our way to work, so we just have to drive.