can “flexible routes” solve the challenge of serving low density?

Whenever I point out that low density areas tend to have low ridership potential regardless of the service offered — as I do at length in Chapter 10 of Human Transit — someone always asks: "But what if we used flex routes or 'demand-reponsive transport''?'

I've added a page — referenced in the book — that tries to answer that question.  It's here.

3 Responses to can “flexible routes” solve the challenge of serving low density?

  1. Miles Bader December 9, 2011 at 6:42 pm #

    A little nit; your article says: “At the opposite extreme, a fully loaded rapid transit train may carry over 1000 passengers an hour with a single driver. A highly performing bus line can hit 100 passengers per hour in a very dense market.”
    I presume the bus line figure is “with a single driver” as well—presumably both train and bus can carry far, far, more passengers per hour once you factor in more frequent service allowed by multiple trains/buses.
    [These figures seem a bit on the low side, even for a single driver… a single crush-loaded train can carry upwards of 3000 passengers, after all…]

  2. Andrew December 10, 2011 at 11:45 pm #

    My impression is that “dial a ride” services are kind of a joke. Basically it’s sort of a shared taxi that you usually have to reserve an hour in advance or so. It’s very inconvenient and choice riders are very unlikely to use it.
    If an area is very low density it is probably best to have the taxi companies provide this sort of service rather than the transit system, because this sort of service is very inefficient. (The very wealthy and low density neighbourhoods of Bridle Path in Toronto and Lorne Park in Mississauga come to mind here. Both have very lightly used bus routes [TTC 162 and MT 14 respectively] that are often targeted for cutbacks by politicians, and would seem possible candidates for this sort of service). In moderate density areas, like the typical suburb in the Greater Toronto Area (houses on small lots and some apartment buildings), the existence of dial a ride services is a sign of underfunding of a transit system and inevitably produces low ridership. Oakville (a suburb west of Toronto) used to replace regular bus routes with this sort of service on Sundays.

  3. anonymouse December 12, 2011 at 5:15 pm #

    The low capacity of flex routes is just an extreme case of a general tradeoff between capacity and flexibility. What makes metro systems so efficient at serving very high numbers of passengers is precisely their inflexibility, and the less flexibility you have, the higher you can push your capacity. Moscow, for example, doesn’t have branched lines, because with 39 tph, it just doesn’t work out, while London’s Central Line has only 30 tph, and works more or less fine with branches at both ends.