Bilevel optimization approach to design of network of bike lanes

A bike lane is an effective way to improve cycling safety and to decrease greenhouse gas emissions with the promotion of cycling. Improvements include high-quality off-road facilities and on-road bike lanes. Whereas construction of off-road lanes is not always possible because of urban land constraints and construction costs, on-road lanes can be a cost-effective alternative. An optimization framework for the design of a network of bike lanes in an urban road network was proposed. This framework identified links on which a bike lane could be introduced. Allocation of a lane to cyclists would increase the use of cycling, although it could disadvantage auto traffic. The presented approach balances the effects of a bike lane for all stakeholders. A bilevel optimization was proposed to encompass the benefits of cyclists and car users at the upper level and a model for traffic and bike demand assignment at the lower level. The objective function was defined by a weighted sum of a measure for private car users (total travel time) versus a measure for bike users (total travel distance on bike lanes). A genetic algorithm was developed to solve the bilevel formulation, which included introduction of a special crossover technique and a mutation technique. The proposed optimization will help transport authorities at the planning stage to quantify the outcomes of various strategies for active transport

The neighborhood environment, physical activity and obesity

The increased prevalence of sedentariness and obesity is a growing concern in public health. However, the factors driving the rise in levels of sedentariness and obesity are not fully understood yet. As individual factors cannot fully explain the rapid increase over a relatively short period of time, there is growing recognition that the environment in which individual behavioral decisions are made plays an important role as well. Environments can be obesogenic by encouraging the consumption of energy dense food or discouraging physical activity or both. Using the analysis grid for environments linked to obesity (ANGELO) framework, this article discusses how different economic, physical, sociocultural, and policy aspects of the neighborhood environment are linked with physical activity and obesity. It is concluded that the literature on environmental influences on physical activity and obesity is still at an early stage of development. Most studies conducted to date lack a clear theoretical framework and have almost exclusively relied on cross-sectional research methods. As a result, substantial scientific uncertainty remains regarding causal relationships and the mechanisms by which environmental components operate

Estimation of the determinents of bicycle mode share for the journey to work using census data

A model is presented that relates the proportion of bicycle journeys to work for English and Welsh electoral wards to relevant socio-economic, transport and physical variables. A number of previous studies have exploited existing disaggregate data sets. This study uses UK 2001 census data, is based on a logistic regression model and provides complementary evidence based on aggregate data for the determinants of cycle choice. It suggests a saturation level for bicycle use of 43%. Smaller proportions cycle in wards with more females and higher car ownership. The physical condition of the highway, rainfall and temperature each have an effect on the proportion that cycles to work, but the most significant physical variable is hilliness. The proportion of bicycle route that is off-road is shown to be significant, although it displays a low elasticity (+0.049) and this contrasts with more significant changes usually forecast by models constructed from stated preference based data. Forecasting shows the trend in car ownership has a significant effect on cycle use and offsets the positive effect of the provision of off-road routes for cycle traffic but only in districts that are moderately hilly or hilly. The provision of infrastructure alone appears insufficient to engender higher levels of cycling

Measuring Lisbon patterns: Baixa from 1650 to 2010

The present study, based on a comparative analysis of several plans for Lisbon’s Baixa district, with an emphasis on that area’s public space, contributes to an understanding of the urban design process and presents a fresh perspective on dealing with historical data by conducting a posteriori analysis using mathematical tools to uncover relations in the historical data. The nine plans used were quantified and evaluated in a comparative manner. While CAD was used to quantify the urban morphology of the different plans, comparative tables make it possible to register the data, which was further evaluated through two interrelated processes: mathematical analysis and the urban analysis. The results show the existence of power law relations for the areas of each of the city’s different elements (e.g., blocks, churches, largos and adros). We discuss how this contributes to the understanding of the plans’ elements

A typology of designs for social research in the built environment

This article presents a typology of designs for social research in the built environment. Currently there is no such typology, while the notion of ‘research design’ is less known in the built environment compared to the social sciences. Twenty-five subtypes are identified and clustered into 10 prototypical designs, namely: (1) surveys, (2) experiments, (3) modelling, simulation, mapping and visualisation, (4) textual and narrative studies, (5) field studies, (6) case studies, (7) intervention research, (8) evaluation research, (9) participatory action research and (10) meta-research. After determining the extent to which these designs feature in actual studies, the designs are classified according to six design considerations, including research – context, aim and purpose, methodological – paradigm and approach, and source of data. The typology contributes towards greater clarity in terms of ‘research design’, improved teaching of research methodology and greater methodological coherence in projects.http://www.tandfonline.com/loi/tsrm2