Abstract

xtabstractThis thesis is a result from a project funded by the co-operative research programme T3 of the Netherlands Organisation of Applied Scientific Research TNO and the Netherlands Research School for Transport, Infrastructure, and Logistics TRAIL TRAIL Thesis Series no. 2006/5, The Netherlands TRAIL Research School, Delft, The Netherland

Abstract

xtabstractProlonged prednisolone treatment for the initial episode of childhood nephrotic syndrome may reduce relapse rate, butwhether this results fromthe increased duration of treatment or a higher cumulative dose remains unclear.We conducted a randomized, double-blind, placebo-controlled trial in 69 hospitals in The Netherlands. We randomly assigned 150 children (9 months to 17 years) presenting with nephrotic syndrome to either 3 months of prednisolone followed by 3 months of placebo ( n=74) or 6 months of prednisolone (n=76), and median follow-up was 47 months. Both groups received equal cumulative doses of prednisolone (approximately 3360 mg/m2). Among the 126 children who started trial medication, relapses occurred in 48 (77%) of 62 patients who received 3 months of prednisolone and 51 (80%) of 64 patients who received 6 months of prednisolone. Frequent relapses, according to international criteria, occurred with similar frequency between groups as well (45% versus 50%). In addition, there were no statistically significant differences between groups with respect to the eventual initiation of prednisolone maintenance and/or other immunosuppressive therapy (50% versus 59%), steroid dependence, or adverse effects. In conclusion, in this trial, extending initial prednisolone treatment from 3 to 6 months without increasing cumulative dose did not bene fit clinical outcome in children with nephrotic syndrome. Previous findings indicating that prolonged treatment regimens reduce relapses most likely resulted from increased cumulative dose rather than the treatment duration. Copyrigh

Abstract

Several cities around the world are facing mobility related problems such as traffic congestion and air pollution. Although limited individually, the combination of bicycle and transit offers speed and accessibility that can compete with automobiles by complementing each other's characteristics. Recognising the potential benefits with regard to accessibility, health, and sustainability, several studies have investigated policies that encourage integration of these modes. However, the actual users and trips of the combined bicycle and transit mode have not been extensively studied empirically. This study addresses this gap by (i) reviewing empirical findings on related modes, (ii) deriving user and trip characteristics of the combined bicycle and transit mode in the Netherlands, and (iii) applying latent class cluster analysis to discover prototypical users based on their socio-demographic attributes. Most trips by this combined mode are found to be for relatively long commutes where transit is in the form of trains, and bicycle and walking are access and egress modes respectively. Furthermore, seven user groups are identified and their travel behaviour is discussed. Transport authorities may use these empirical results to further streamline integration of bicycle and transit for its largest users as well as to tailor policies to attract more travellers.

Abstract

Within the departments Environmentally Sustainable Transport and Automotive of TNO (Netherlands organisation for applied scientific research) several projects investigating safety aspects of electric vehicles have been conducted, including one in cooperation with KEMA and RDW of the Netherlands. Most attention in these projects was given to cars that were converted to electric, starting from conventional vehicles. This choice was made because most of the electric vehicles present in the Netherlands are of the converted kind. Only recently larger numbers of OEM Electric Vehicles have become available. In the study practical safety guidelines for the companies involved in the conversion business have been established. In general it can be concluded that converted vehicles carry greater safety risks due to the way they are made (retrofit) and different, less stringent approval tests for individually modified vehicles. This study presents a strategy to -focusing on safety- optimally convert to electric. Electric, functional as well as crash safety were covered and recommendations were given for each.

Abstract

Does consideration of average speed distributions on roads-as compared to single mean speed-lead to different results in emission modelling of large road networks? To address this question, a post-processing method is developed to predict mean speed distributions using available traffic data from a dynamic macroscopic traffic model (Indy) that was run for an actual test network (Amsterdam). Two emission models are compared: a continuous (COPERT IV) and a discrete model (VERSIT+macro). Computations show that total network emissions of CO, HC, NOx, PM10 and CO2 are generally (but not always) increased after application of the mean speed distribution method up to +9%, and even up to +24% at sub-network level (urban, rural, motorway). Conventional computation methods thus appear to produce biased results (underestimation). The magnitude and direction of the effect is a function of emission model (type), shape of the composite emission factor curve and change in the joint distribution of (sub)-network VKT (vehicle kilometres travelled) and speed. Differences between the two emission models in predicted total network emissions are generally larger, which indicates that other issues (e.g., emission model validation, model choice) are more relevant. © 2007 Elsevier Ltd. All rights reserved.

Abstract

Home to work travel remains the prime focus of mobility management policies, in which the promotion of carpooling is one of the main strategies. Besides governments, employers are key players in this strive for a more sustainable commute. However, commuting research tends to focus on individual commuters and their place of residence, rather than on workplaces and company-induced measures. Therefore, this paper takes the workplace as research unit to analyse the popularity of carpooling in Belgium. After an exploratory (spatial) data analysis, we incorporate three groups of factors in a multilevel regression model which predicts the share of carpooling at large workplaces: location (accessibility), organisation (activity sector), and promotion (carpool-oriented mobility management measures). Higher levels of carpooling are found at less accessible locations, and in the activity sectors construction, manufacturing and transport. This analysis gives insight in the determinants of carpooling, and may thus contribute to the development of sustainable transport policies.