A Theory of Modes
Wikipedia's article List of transport topics gives a list of a variety of modes largely defined by their technology (are they powered by animals or engines, are the engines on the vehicle or is the vehicle powered by a cable, do the vehicles travel on land, sea, or water, etc. While this is a reasonably comprehensive list and a reasonable organization of the subject for wikipedia, it does not really get at the transportation aspect of modes, focusing instead on their mechanical aspects. I propose a schema that classifies passenger modes according to how they operate, not how they are paid for or what technology is employed: The key attributes are: * Availability (can you travel on demand, is a vehicle easily hailed, or is a reservation required?), * Accompaniment (can your party travel alone, or is the ride shared with others?), * Fixity of route ends (are the origin and destination of the route fixed?), * Fixity of route stops (are the stops fixed, or does the vehicle stop anywhere between the origin and destination?), * Fixity of schedule (does the vehicle adhere to a schedule?), * Driver (does the party drive itself or rely on others?). In this way, we can see the similarity or differences of seemingly different or similar modes.
Accompaniment Route Ends Driver Stops Schedule Example On-demand Own Party Variable Self Variable Variable Car Motorcycle Bicycle Walking Carpool Variable Other Variable Variable Taxi Fixed Other Variable Variable PRT Shared Variable Other Variable Variable Shared Taxi One end fixed Other Variable Variable Airport Express, Hotel Van Two ends fixed Other Variable Variable Jitney Other Fixed Schedule Bus Other Fixed Stops Variable Elevator, People Mover Other Fixed Schedule Rail, BRT Other Nonstop Variable Stagecoach Express Bus/Train By reservation Airline Own Party Variable ends Self Limosine Other Car Share, Car Rental Shared Variable ends Paratransit