Impact of Urban Structure On Personal Transportation in the Context of a Large Danish Provincial City
T S Nielsen, Aalborg University, DK
This paper presents the results from a detailed study of the land use ? transport connection, with special emphasis on the location of residences, in the context of a larger Danish provincial city (the city of Aalborg with approx. 120.000 inhabitants, situated in North Jutland). The study was carried out as a part of the authors PhD-work and as part of the research programme: Transportation and urban structure at Aalborg University.
The land-use transport connection is investigated empirically at the micro-level with three different approaches, quantitative as well as qualitative. The backbone of the study is a broad household/individual administered survey in 23 selected neighbourhoods. Some 1200 individuals responded to the survey with 1-week odometer-readings on household cars and a one-week account of personal travel by modes. The broad survey was followed by a 7-day detailed travel-diary among volunteers from the first survey, and eventually qualitative interviews were held with members of 16 strategically selected households.
Multivariate regressions were used to allow conclusions on the significance of urban-structure variables controlling for life-style or other household/individual attributes influencing the consumption of transport. A large number of urban structure variables at city and neighbourhood-level were included in the analysis together with socio-economic-, demographic-, attitude- and social-background variables. Urban structure variables was mainly focused on the location of the dwelling and a special effort was made to measure on the basis of actual locations as opposed to relying on characteristics of zones and zone data. The detailed travel diary data was especially used for GIS-based analysis of spatial patterns in trip destinations. Together with the qualitative interviews this allowed a further investigation into the mechanisms through which the urban structure influences transport.
An overall conclusion is that the location of the dwelling vis-à-vis the CBD/Urban core is strongly related to the consumption of transport, transport by different modes and energy use for transportation. In the case of personal transport inside the city municipality the distance to the CBD is actually the single most important explanatory variable ? more important than the respondent?s access to a car. This finding contrasts the many studies doubting or lending some limited support to the significance of urban structures. The centrality variables position as ?number one? in the explanation of transport inside the municipality is of course also a consequence of the many control variables included in the study. The urban structure variables do however lift the regression models level of explanation with 6 percentage points (from R-square 0,15 to 0,21) when they are included. Thus the contribution from urban structure to the explanation of transport consumption is substantial.
The significance of the distance from the dwelling to the CBD is consistent with many other studies from Europe and especially the Scandinavian countries. It is however important to recognize that this is only a description of how it is at present. The distance from the dwelling to the CBD as an explanatory variable may be perceived as a proxy for a agglomerate of factors all contributing to the apparent significance of the CBD, - but inseparable in a relatively monocentric north European city, grown around a medieval core. Besides the attraction of the CBD itself with its shopping, cultural and entertainment facilities, the CBD is also the centre of gravity in the area, and transport node for especially public transportation and to some extend also for road transportation. Attempts to replace the distance to the CBD with other urban structure variables in the analysis ? and - the general patterns of trip destinations revealed by the travel diaries, - suggests that the role as centre of gravity is likely to be one of the most important factors behind the significance of distance to the CBD.
The choice of destinations for most trip-purposes is likely to support the correlation between distance to the CBD and transport consumption. Based on the high frequency and regularity with which such trips take place ? and the mechanisms by which people get a job, the commute is likely to be one of the most important pillars behind the relation between centrality and transportation.
Other urban-structure factors were also shown to influence transportation in different ways. Among the most important of these factors where the location of the dwelling vis-à-vis the external centre (shopping and employment) together with a number of factors related to the geographical context in which the city of Aalborg is located (its separation by a fjord and its location at the north ?far end? of the country). The presence of neighbourhood facilities (shop, school etc.) was especially found to promote transportation on foot and bicycle, with a likely, but not very strong, reduction in motorized transportation as the result.
Association for European Transport