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 This project seeks to consider the potential significance of travel time and more particularly travel time use in the future of mobility. Its focus is on the use of the bus and train in the context of car travel. This section provides the context and rationale for the study. Firstly, a brief overview of personal travel is given. Some key established conventions concerning travel time are then summarised. The research hypothesis for the study is then presented. Finally, a series of research questions arising from the hypothesis are provided.
Personal travel in the information age
The level of mobility in many societies has grown dramatically. Personal travel across modes
in the UK, when measured in billion passenger kilometres, increased from 218 in 1952 to 728 in 1999
with an increase in the last decade alone of some 7 per cent [1]. Between 1972 and 2000 the average
annual distance travelled per person in the UK increased by 53 per cent. Over the same period
the average number of trips increased by only 8 per cent and the time spent making these trips
increased by only 2 per cent [2]. However, the average time spent travelling appears remarkably
stable at around a little over one hour per person per day. Increases in journey speed
(achieved by changing modes or because of improvements to the transport system) are responsible
for enabling people to travel further - increasing their spatial range of access to people,
goods, services and opportunities.
Most of the increase in mobility has arisen through substantial increases in car use.
In 2001, in terms of total domestic distance travelled, car travel accounted for 85
per cent of the total compared with 6 per cent for rail and 1 per cent for air.
However, in terms of the increase in travel by each of these modes over the period 1991-2001,
whilst car travel grew by 7 per cent, rail travel increased by 21 per cent and air travel by 60 per cent [3].
This would suggest that, particularly as congestion on the road network worsens, the trend in
'further and faster' travel will be bolstered by increased use, particularly for
longer distance travel, of the (sometimes) faster modes of rail and air. One half
of UK citizens now report taking an air flight in any year [4].
The information age appears to be supporting such a life on the move.
The proportion of households with at least one mobile phone has almost tripled
from 17 per cent in 1996-97 to 47 per cent in 2000-2001 [5]. Ownership of laptop and palmtop
computers (and games consoles) has also increased in parallel with their increasing
capabilities and affordability (and increasing wireless connectivity). While not true
of all travellers, it seems very many people are accompanied by mobile technologies when
on the move. These allow communications between people irrespective of spatial separation
and allow a working or entertainment environment to be created during a journey, or even
for arrangements only to be finalised while actually on the journey. People are moving
and communicating rather than doing one or the other [6]. Indeed new railway rolling stock
(the Virgin Voyager) provides power points in standard class for the use of laptop computers
and mobile phones. Vodaphone is currently promoting widely its next generation phone services
with colour-screen devices that can capture, send and receive images to apparently enrich
the experience of use for its customers.
Some established conventions
There are three conventions that we wish to challenge in light, particularly,
of the opportunities that the information age is providing to undertake activities while travelling:
Travel time is unproductive 'lost' time: When undertaking a journey in order
to participate in an activity at an alternative location, an individual 'invests' time.
Transport scheme appraisal in the UK has, since the 1960s, been based on an assumption
that time spent travelling during the course of the working day is unproductive wasted
time and therefore a loss to the economy. Time spent travelling at other times
(including commuting) is costed according to an individual's willingness to
trade time for money. Accordingly, travel time savings have usually been the
principal financial benefit of a scheme - these have generally been taken to
account for over 80 per cent of road scheme benefits [7]. This interpretation of
the value of travel time has significantly shaped the current UK transport system [8].
Levels of mobility are constrained by a travel time budget: There is historical global
evidence to suggest that, at the aggregate level, "people spend somewhat more than one
hour per day travelling, on average (travel time budget), despite widely differing
transportation infrastructures, geographies, cultures, and per capita income levels" [9].
In other words, the time that individuals in society set aside for mobility seems finite,
limited and broadly fixed, regardless of variations in many other factors. The travel time
budget dictates that as the means of travel become faster, distance travelled will increase,
or, conversely, that the need or desire to travel further will be accompanied by a requirement
to develop faster modes of travel. If travel speeds have an upper limit, it follows that
aggregate mobility levels (as measured by passenger kilometres) will also have an upper limit
(although whether its distribution between members of a given society remains the same over time
is less certain).
Travel time and activity time are discrete: Applied travel demand modelling has traditionally
followed a trip-based approach. More than 20 years ago an alternative approach became
the subject of research. This is known as the activity-based approach because it
is based on the idea that travel demand arises, or is derived, from the desire
or need to participate in activities. "The development of the activity-based
approach to travel demand analysis is characterized by a desire to understand
the phenomenon of urban travel, not merely to develop predictive models that appear
to produce acceptable forecasts" [10]. The activity-based approach holds the prospect
of more realistic representation of patterns of travel in time and space. Nevertheless,
this still treats travel time and activity time as separate albeit with assumed interdependencies.
The research hypothesis
Our principal hypothesis is:
The validity or not of a constant travel time budget is not central to the hypothesis.
It is included to highlight that productive use of travel time has the potential
to overcome or extend any notional fixed limited to society's overall level of mobility.
If such a fixed limit does not exist then the hypothesis still points towards the
productive use of travel time, enabling possibly the level of mobility to increase
even further. This hypothesis is increasingly significant as the information age
develops to meet 'any place, any time' lifestyles.
The research questions
The hypothesis in turn raises many important questions to be researched in this project within the UK.
The project has identified four pivotal research questions:
References
[1] DETR (2001). Transport Trends: 2001 Edition. Department for the Environment, Transport and the Regions, March, TSO, London.
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