change is necessary in the way we use public transport, and the COAST concept addresses the fundamental
reasons for vehicle inefficiencies and subsequent CO2 emissions, passenger utilisation.
In conjunction with other initiatives proposed on this site such as electrification and radical size reduction,
COAST should enable a rapid and substantial reduction in overall CO2 emissions from the transport sector. See
figure 34 for a comparison of CO2 per passenger km with other modes of transport discussed in this report.
Examples of the Advantages of COAST
Whilst cost and time comparisons are difficult the estimate between transport modes, it is possible to provide
illustrative examples of the advantages of COAST verses the bus, conventional taxi, shared taxi, shared car and
private car by using time estimates for each part of the journey. These elements can then be summated to
calculate the door to door time, which is the time interval between when the driver or passenger actually
wishes to depart from their present location, and arrive at the final destination. This more realistically
characterises what is important to the traveller when choosing between transport options.
Costs are calculated for COAST and compared with the private car, taxi and bus as a function of distance
allowing the following time and cost factors: See the spreadsheet for further details
Walking time: the time required to walk to and from the bus stop or car parking location.
Waiting time: the time taken to wait for the bus, car or taxi assuming it is available.
Extra waiting time due to unavailability: the extra time waiting for a taxi service during certain
periods of high demand.
Extra time to find parking space: the time taken to find a legal parking space.
Extra time for passenger stops: the extra time taken due to having to slow down, wait and accelerate
back up to speed purely for the purpose of picking up and dropping off passengers
Extra time for diversion: the extra time taken due to having to divert off the desired optimum route
for all shared vehicles for the purpose of picking up and dropping off passengers
Reduced time due to use of dedicated lanes & short cuts: it is suggested that COAST activated
vehicles and shared taxis are allowed the use of a wide range of dedicated lanes and short cuts not
available to other cars.
Average speed kph ignoring drop offs: Average speeds of 20, 40 and 60 kph are assumed for high,
medium and low demand conditions respectively
Taxi driver Costs £/hr These are estimated from a standard taxi charge. The inflation adjusted values
for private driver costs/hr are used from the ELECAT tables
Taxi and driver costs £/km These are estimated from the standard taxi time charges converted to
distance using the assumed speed. The inflation adjusted values for private driver costs/km are used
from the ELECAT tables
Individual time This is the cost due to the time element of travelling, and is identical for COAST
drivers and passengers in all modes of transport
Fixed fees £/journey This encompasses the fixed charge fee for a taxi, or the parking fees for a private
car which is waived for the passengers. The low demand scenario assumes free parking is available
Bus costs £/km are calculated from separate data based on the total revenue from fares and subsidies
divided by the total passenger km driven
The calculations are repeated for high medium and low demand travel scenarios which correspond to average
vehicle speeds of 20, 40 and 60 kph (see figures 3 to 8). In the 1% and 10% COAST modes it is assumed that
1% and 10% of cars on the road are COAST activated respectively.
The low demand scenarios in figures 3 and 4 illustrate the time and cost advantages provided by the private car
(dark blue line) relative to the other transport modes. This is due to the ability of private car to be used
flexibility on demand and the lack of waiting times unlike taxis and public transport. Also evident is the
uncompetitiveness of the bus in terms of both time and cost.