The National Research Programme (NRP) 41 was launched by the Federal Council at the end of 1995 to improve the scientific basis on which Switzerland's traffic problems might be solved, taking into account the growing interconnection with Europe, ecological limits, and economic and social needs. The NRP 41 aimed to become a think-tank for sustainable transport policy. Each one of the 54 projects belongs to one of the following six modules:
- A Mobility: Socio-institutional Aspects
- B Mobility: Socio-economical Aspects
- C Environment: Tools and Models for Impact Assessments
- D Political and Economic Strategies and Prerequisites
- E Traffic Management: Potentials and Impacts
- F Technologies: Potentials and Impacts
- M Materials
- S Synthesis Projects
Better access to various locations and services is, in many cases, an objective of transport policies. However, it is not easy to find simple, meaningful measurement units for accessibility: firstly, one must gain an understanding of how the various aspects of accessibility (such as required time, price, quality of connections) are weighted by the travelling public. The study wants to provide a broad overview of various accessibility concepts and mobility requirements. The study aims to build methods and indicators allowing a better measurement of the accessibility of the population to various locations and activities (such to work, leisure, etc.) by taking into account the location (in the centre town, in suburbs, in the countryside) and the socio-economic characteristics (age, income, activity). The long-term aim of this study is a sustainable transport policy, reconciling the request for mobility - present and future - with the requirements of economic efficiency, social justice and environmental protection. This objective is part of the new strategy of the Swiss Ministry of Transport (DETEC).
The research was carried out in four stages:
In the first stage, we posed the methodological bases of the measurement of the access and look further into the theoretical aspects related to these questionings;
In the second stage, we validated our step with the design and the realisation of an investigation near the households of the canton of Vaud. The initial intention was the realisation of a national investigation relating the access to three various opportunities (work/training, shopping, leisure). Because of the high costs to carry out the investigation, the scale had to be adapted to the financial availability. Further the agreement of the programme's management, the investigation was carried out on 540 households of the canton of Vaud and explored the requests of access to the leisure and places of work. This investigation leads us to better know the sensitivities of the users towards access and to collect the data necessary to the realisation of the indicators of access;
The third stage consisted of the construction and the experimentation of the pilot indicators of access, potentially usable in the implementation of local, regional or national policies of transport;
Lastly, in the fourth stage, various aspects relating to the modal choice criteria were analysed through a qualitative investigation probing the stated preferences towards access on a sub sample of households resulting from the first investigation.
1. The investigation and key results
The access to work and leisure places was the subject of a sample survey (by phone), on the basis of sample representative of the households, according to its geographical distribution in the canton of Vaud (urban centre, commune of agglomeration, non urban commune). The results of the survey reveal a 'demanding' request on behalf of a population which counts 'less and less' its money to move. In a brief way, the key lessons are:
The predominance of the use of individual transport (65% of residence-work displacements, 77% of leisure's displacements). The public transport and soft means of transport are more used to go to work, than to reach the leisure place;
The time is generally lower than 20 minutes (66% for work and 68% for leisure), consequently the distances are relatively short (lower than 10 km for 58% of movements for the work and 64% for leisure);
50% of the workers have a car at disposal even if they don't use it versus 42% of the people moving to practise leisure; the assets of the other means of transport were thus dominating the modal choice ;
More than half of the sample declare access costs to work lower than 150 CHF, the highest costs (from 100 CHF/month) are especially supported by the car users. For leisure, costs are generally lower than 10 CHF by movement (63% of sample);
General conditions of the displacement (which includes security, reliability, physical comfort, etc.) represent the principal modal choice factor for 38% of work displacements and 42% of displacements related to the leisure. This result is relatively surprising for pendular displacements where one could expect a greater part of people privileging the time of displacement (19% work and 16% leisure) or the cost of displacement (3% work and 2% leisure);
Two thirds of the pendular using car do not have parking fee on their place of work, more than 90% of the practise of leisure also do not declare any cost of parking;
A lot of persons considered the
At the end of this research, several major lessons can be drawn; they concern:
Access represent a field of search still little explored; in all the cases it is located well beyond the transformation into money values of the components of the request for movement. To measure the access presupposes taking into account 'objective' elements (transport supply at one time and in a space given, types of opportunities) and 'subjective' elements (like the importance allotted by the user to the opportunities to reach or qualities requested for the movement).
The indicator of access build in this search is a measuring instrument which combines the resources necessary to movement with the frictions (objective and subjective) acting on a same displacement. The formulation suggested is interesting while it considers needs and waitings of the users, in terms of transport, with the importance allotted to the factors the such cost, conditions (comfort), time and environmental effects.
The investigation highlighted two hierarchies of the modal choice criteria: the 'hierarchy of the needs' resulting from a concatenation for events and constraints, and the 'hierarchy of the values' reflecting the normative structures, the beliefs and the values in which individuals identify. This differentiation of the importance of the factors of choice lets appear many questionings: all could not be detailed in this research (cf. next point). The qualitative investigation showed the existence of allowance's thresholds of the resources to be devoted for the realisation of movements.
The concept of access and the process of modal choice constitute rich topics, because they allow not only the description of the mobility's behaviour, but they also clarify their 'objective' and 'subjective' reasons. Many questionings remain evidently unanswered and further developments are necessary as well from the point of view of the opportunities considered, of the indicator of access and of the qualitative investigation. In particular, the double hierarchy of the factors of choice constitutes the starting point for the best taken into account of the transport demand in the development of local and regional policies of transport.
The concept of access and the process of modal choice constitute rich topics, be