Saturday, May 28, 2005

Making public transport faster

One performance measure of public transport effectiveness is its travel speed versus alternatives such as driving, cycling and walking.

For a fair comparison, total origin to destination travel times should be used; not just in-vehicle times. Thus minutes spent waiting, transferring and finding a parking spot should all be counted.

The ratio between public transport and car travel time is particularly important. During peak times, where origins and destinations are near the same rail line and services are frequent, public transport can exceed the speed of car travel.

At other times public transport is generally slower. If the PT:driving time difference ratio isn't excessive (say less than 2:1) people may still accept this if public transport offers other advantages (eg cheaper, no parking hassles, able to read when travelling).

The real worry is where the ratio is much higher. This is true for many local trips, where a 15 minute drive translates to a 60 minute public transport trip, ie a ratio of 4:1. With this sort of difference, only those who have no choice will persist in using public transport.

To make public transport faster, we need to seek time savings in each component of the public transport trip. These components are:

a. Walking to and from bus/tram stop or station

b. Waiting for service to arrive

c. Ticket purchase and validation

d. In-vehicle travel time

e. Interchange time (includes walking + waiting)

As a proportion of total journey time, a, b, d and e are the most significant. When expressed as perceived time (which seems longer than actual time when one is not moving), b and e are most critical.

Possible improvements for each of these components are as follows:

a. (i) bus/tram stops located at intersections (ii) fast, direct and safe pedestrian access to stops from the surrounding area (iii) pedestrian and transit-friendly urban design {notably permeable street layouts}

b. (i) more frequent services (ii) clockface/memory timetables (iii) timetables at stops (iv) real-time passenger information {so passenger can consider alternatives}

c. (i) pre-purchased tickets

d. (i) tram and bus priority over cars (ii) more direct routes

e. (i) timetable co-ordination {including harmonised headways} (ii) more frequent services (iii) good transfer point design, including fast, direct and safe pedestrian access between all transfer points and to surrounding streets (iv) timetables at stops (v) real-time passenger information {as passenger can consider alternatives}

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