Where Does Carsharing Fit in the Scheme of Transportation Modes?

By: Khondoker Hafizur Rahman on 1:30 AM

When I was first getting interested in carsharing, way back in 1996, I
came across a wonderful graphic that really helped me understand the
role of carsharing in transportation.  You've probably seen this graphic
in numerous Powerpoints — which modes are best for which types of
trips, based on the Distance of the trip and amount of Flexibility
(time, destinations) needed during the trip.

I first saw the graphic on Eric Britton's foundational website and e-mail discussion group at World Carshare Consortium,
which is still alive and well (as is Eric, who has created more website
and discussion groups since then than I can keep track of!)  He told me
that the original source, from 20 years earlier, didn't actually call
it carsharing but the term "paratransit"(after all the term wasn't
coined until 1987 when carsharing as we know it got started, almost
simultaneously in Switzerland and Germany).  Somewhere along the line,
the word Carsharing got substituted and the chart became history.

 (From Ron Kirby and Kisten Bhat: Para-transit: Neglected options for urban mobility, Urban Institute, 1974)



Well, that graphic was history, until now. But even carsharing evolves
and now we have a new flavor - one-way/on-demand carsharing (e.g.
Autolib, Car2Go, Enjoy, JoeCar), which has somewhat different trip
characteristics.  So I was very pleased to find an updated version of
this chart from Marco Viviani of CommunAuto, Montreal, showing the place
for One-Way.

Something that Viviani's graphic does very nicely is to convey what
those swirly black line arcs in the upper graphics represent - the
possible overlap between modes.



One might argue that the One-Way bubble should really be a big elipse
that also slightly overlaps with Public Transit, since the most recent
evaluations show a slight decrease in transit trips by one-way users.
 (But, for what it's worth, I would suggest this should not be a big
concern since these are likely trips that would have been difficult to
do on transit - either because of time and schedules or because of the
number of changes required.)



I suppose one could include Uber, Lyft and Sidecar in the Taxi category,
if you really wanted to update it.  The next question will be where
autonomous cars belong on the chart?