Draft:Demand Responsive Transport

		Scheduled Bus	Demand-Responsive Travel			Taxis etca
			One-to-Many	Many-to-One	Many-to-Many	Uber Pool	Uber X	Taxi	Minicab
Scope:	Who it carries	Anyone	Variesb			Anyone
	Shared with others?	Yes	Yes			Yes	No
Flexibility	Start Point	Fixed	Fixed	Flexible within a specified zone	Flexible within a specified zone	Flexible within a specified zonec
	End Point	Fixed	Flexible within a specified zone	Fixed	Flexible within a specified zone	Flexible
	Timing	Fixed	Fixed Departure	Fixed Arrival	Flexible within scheme operating hours	Flexible: 24/7
Predictability: Can you make firm plans several weeks ahead?		Yesd	Rarelye			Nof	Yesg	Yesh
Can you make firm plans a day or two ahead?			Sometimesi
Available to use at a few minutes' notice?			Where no advance bookings taken: Oftenj			Usuallyl		Often
			Where advance bookings are taken: Possiblyk
Available to use instantly?			No			No		Often	No
How fast?	At best	Fastm	Fastn			Moderateo	Fast
	At worst	Slowp	Slowq		Slowr
Relative cost before any subsidy	At best	Lows	Moderatet			Moderate		Moderate
	At worst	Highu	High			Highv

Notes

a.^ Uber Pool is a shared-use service. Uber X provides exclusive use (also covers Uber XL, Uber Green, Uber Comfort, Uber Exec). "Taxi" describes a service that can be hailed on the street or contracted at a rank in the street - sometimes known as a "Hackney Carriage", as opposed to "Minicab" (or "Private Hire") which covers services that require pre-booking (by app, phone or at an office) but are not permitted to pick up on the street or from a rank.

b.^ Many DRT schemes carry anyone. Some schemes may be limited to qualifying categories of user (eg mobility impaired) or for specific purposes (eg medical appointments)

c.^ Uber Pool (shared) is only offered in specific city-centre zones, which are smaller than the overall operating area offering exclusive-use Uber X. Taxis and Minicabs are often restricted to picking up within a local licensing area.

d.^ Timetable changes for scheduled bus services are rare, and generally notified well in advance (eg UK specifies six weeks' minimum notice). There is a risk is that you are refused permission to board the vehicle because it is too full on arrival at the stop where you are waiting. On rural services using vehicles which have been sized for school journeys (and so offer much more capacity than the operator would ideally supply), such a risk will be very low

e.^ Few DRT schemes offer far-ahead advance booking: where advance bookings are taken, this is most commonly 7 days ahead. In this setup, the only scope for being sure that you will be able to travel several weeks ahead is when utilisation is low enough that there will always be several days between the opening of advance bookings and the point when the schedule will have filled up to the point where the requests first have to be rejected as unfeasible.

If the schedule fills up very quickly once bookings open, then anyone wanting to make plans before the start of the booking period (eg for a hospital appointment six weeks ahead where bookings open 7 days ahead) faces the risk that they won't succeed in booking a journey to match their commitment. And if the scheme is immediate-reservations-only (eg ViaVan) then there will be no way of knowing whether you can travel until a few minutes ahead of the time of travel (at which point it is generally too late to arrange an alternative that will get you to your destination at the intended time).

f.^ Uber works on matching riders to drivers in real time. Their "scheduled ride" offering in fact consists of recording your requirements in advance, but for that requirement only to be activated in the system a few minutes ahead of your ride time. Uber do not pretend to offer any "guarantee" (although some press use the term) but do offer a $10 credit for a future ride where an advance booking is not honoured. You CAN book ahead, but there is no attempt to reserve capacity: your booking takes its chance to get an immediate allocation of driver when the time comes. Uber doesn’t guarantee that a driver will accept your ride request. Your ride is confirmed once you receive your driver details.

g.^ Uber have started offering (in some cities only so far) the option to "Schedule Premium Uber Rides in Advance", with the chance to indicate a preferred driver. As with "scheduled rides" there is no absolute guarantee, but they offer an "appeasement" of "up to $50 in Uber Cash" if they fail to honour the booking. It is unclear whether this involves a fundamental change in scheduling, or just a prioritisation of these premium bookings, which might still only launched into the system a short while ahead of the booked time.

h.^ Taxis and Minicabs will generally take bookings a long way in advance, but are not 100% reliable: a previous trip may over-run, a driver may call in sick, or a vehicle may go out of service.

i.^ Where advance DRT bookings are accepted, early bookings will shape the schedule, with successive requests having a reducing chance of fitting with the schedule already committed. Requests made a few days ahead (but after the day that bookings open) can sometimes fit with the schedule as it stands, and will sometimes be accommodated by a change in schedule that does not jeopardize existing commitments. Otherwise, those attempting to book after the rush of bookings at the start of the booking window may be offered a trip at a different time, or not at all.

j.^ For dynamically-scheduled services (eg ViaVan), advance bookings are not offered: the schedule is built dynamically as requests come in as passengers are ready to travel. Your request is accepted or rejected depending on whether it the schedule can be amended to accommodate your trip whilst still respecting the commitments made to those booking before you. Success in booking trips will be high when services are first launched (because usage is low), but will tend to decrease as customer numbers grow. When projecting the steady-state costs of a DRT scheme, there is a need to predict the minimum acceptable chance of successfully booking a ride (and therefore the maximum level of utilisation that can be achieved).

k.^ Late DRT bookings are possible where there is still space, for passengers whose journey fits with the route that has already been planned, or which can be accommodated by a change to the schedule (without breaking promises already made to other passengers) - up to the last time when this can be communicated to the driver.

l.^ Uber is designed for maximum availability: "surge pricing" is designed to reduce the risk that there is too little capacity at any time, but Uber concede: "There are times when so many people are requesting rides that there aren’t enough cars on the road to help take them all"

m.^ Scheduled bus is fast for trips when the bus route has few deviations from the most direct route between your start and end points.

n.^ DRT is fast when the route is direct and scheduling constraints allow it to serve your ideal start/end point at the times you want.

o.^ Speed of Uber Pool is only moderate where you suffer deviations off the fastest route or other delays to pickup up or drop off others. Uber say that they plan to limit total journey time for each Pool rider, so avoiding the "round the houses" scenario of greatly extended journey times.

p.^ Bus is slow when the nearest stops are distant from the ends of your journey, and/or where the route between your start and end stops involves substantial deviations and/or when the timing of services matches your travel times badly.

q.^ DRT is slow when the service takes you on a circuitous route to accommodate needs of other passengers, and/or when schedule constraints means that it cannot take you exactly where you want to go

r.^ DRT is slow when you get taken "round the houses" before reaching your destination - potentially taking a very long time. Likelihood depends on other riders' needs and on the operator's appetite for efficiency over customer experience.

s.^ Scheduled buses can have much lower cost-per-passenger on busy routes

t.^ Even when there is strong demand, DRT can be more expensive to run than a scheduled bus service. In rural areas where home-to-school transport is the dominant bus use, middle-of-the-day scheduled services need only to cover the marginal cost of fuel, wear-and-tear and (depending on agreements) driver hours, as the fixed costs (purchase price financing, depreciation, insurance) will be incurred for the school services whether the extra services run or not. In this scenario, introducing DRT using smaller vehicles sees the service having to carry the additional fixed costs of a second fleet of vehicles. The nature of DRT routes and the size of vehicles means that they will never, if used as intended, run at really high occupancy.

u.^ Cost of scheduled bus climbs quickly as passenger numbers drop.

v.^ Cost of Uber can be much higher than taxi or Private Hire when "surge pricing" is in operation.