Travel distance computation from household travel survey data: The case of Microcensus 2000

Distance related information that has been collected from the travel surveys requires an in-depth analysis for the quality assessment of the directly reported distance data. This paper reports the issues involved in different distances calculations and comparing the same. The objective is to assess the accuracy of the reported travel distances. This report briefly introduced the loaded network distance and comparison of network distance, geo-code based crow-fly distance and the reported travel distance. Data that was collected in 2000 Microcensus is used for comparison. This sample data has been thoroughly screened and only within day car travel was considered for analysis. Variations in trip length distributions of reported distance and the calculated distances are observed. It is found that the reported distances are in between shortest path distance and loaded network distance. Using a descriptive statistical analysis, a series of detour factors are computed for different travel distance ranges. An average detour factor (operational) of 1.61 is obtained form the analysis. Accuracy of the reported information about origin and destination of the long-distance trips is assessed in the end

Archiving travel data: The Mobidrive example

The paper discusses the necessity and importance of archiving transport data, in particular travel behaviour data. It explicitly identifies the inefficient efforts in public usage of transport data. Though there are many organisations/institutions working seriously on archiving data in social sciences sector, a specific transport data archive was not yet been. The paper provides the methodology to archive a typical transport data. Various tools used in archiving data are described. An open methodology is provided in order to take care of the diversity of data formats. Mobidrive- a six week travel diary was archived at Institute of Transport planning and Transportsystems (IVT), ETH Zurich. The issues raised and the way they were addressed while archiving a long term travel behaviour dataset are discussed in this paper. The salient features of secondary usage of the archived data are emphasised. The tools useful for secondary analysis are described. Safe and secure data issues also are addressed from data administrator’s perspective

Precision of geocoded locations and network distance estimates

This paper addresses three questions: how accuraate is the geocoding of travel diaries; what are the relationships between different network-based distance estimates, and how exact are estimates provided by self-reported distances. Three large-scale surveys in Norway and Switzerland demonstrate that very high precision is possible when survey protocol emphasises capture of addresses. The necessary databases and networks are available today. Crow-fly, shortest-distance path, shortest-time path, and mean UE path distances are systematically related to each other, the pattern of their relationships matching theoretical expectations and the resolution of the networks used. In the examples studied, medians of self-reported distances by distance band provide reasonable estimates of crow-fly and shortest-distance path distances