working paper

The Relationship of Neighborhood Built Environment Features and Walking

Abstract

To date, the literature on urban design and walking has often emphasized more macro-scale features, such as block length and number of intersections, that are easier to measure remotely using GIS and or aerial photographs. Urban designers, in contrast, emphasize the importance of micro-scale features in individuals’ use and experience of neighborhood environments. This paper moves beyond examining correlations of individual built environment features and walking, to begin to test proposals about which composite characteristics of the built environment (safety, comfort, etc.) may have the greatest impact on walking. Several urban design characteristics of 11 neighborhoods throughout California were collected. Self-report walking data on the number and types of walking trips were obtained from surveys administered to parents of 3rd-5th graders. Urban design features related to both accessibility and safety affect the amount of walking that adults do in their neighborhood. Grouping related urban design variables into indices provides some clarity as to how the built environment impacts walking. Safety emerges as the most important built environment characteristic (of those tested), related to both destination and recreational walking.

working paper

California's Safe Routes to School Program: Impacts on Walking, Bicycling, and Pedestrian Safety

Abstract

Safe Routes to School (SR2S) programs have generated tremendous interest among U.S. policymakers, planners, and public health officials in recent years. These programs target the walk to school as an essential point of intervention to improve pedestrian safety and increase physical activity among children. In this article, we evaluate California’s pioneering SR2S construction program, which was designed to improve safety for children’s walking and bicycling to school, and to increase the number of children who do so, by funding traffic engineering improvements around schools. Through a systematic evaluation of 10 California SR2S traffic improvement projects near elementary schools, we examined the impacts of this influential state policy on children’s travel behavior in these neighborhoods. We investigated changes in the perceived safety of children’s trips to school, in safety-related behaviors tied to the trip to school, and in the number of children walking and bicycling to school following these improvements. The findings have implications for California’s SR2S program and for similar initiatives throughout the country.

working paper

Travel Behavior Comparisons of Active Living and Inactive Living Lifestyles

Publication Date

August 31, 2006

Author(s)

Konstadinos Goulias

Abstract

The past century’s radical change, innovation in transportation technology and concomitant increase in options for our travel modes moves us away from walking to an almost total extinction of modes that require physical exercise. This is accompanied by a modern American city design that requires the use of an automobile with urban sprawl creating distant destinations that alter older methods of travel and make active forms of transportation almost impossible. However, many more reasons exist that motivate people to choose physically inactive modes as our research shows here. Using a two-day activity diary collected in Centre County Pennsylvania, we identify which factors influence active versus inactive mode choice. In this analysis, we examine the correlation between trip purpose and travel mode, the correlation between age and travel mode, and perform an analysis of travel distances to determine what the distance threshold is for active modes. In addition, a latent class cluster analysis establishes a profile for both physically active as well as inactive travelers and their correlation with person and household characteristics. Key findings include that trips made using active modes are significantly different than trips made by inactive modes and persons with active transportation lifestyles are significantly different than persons with inactive lifestyles. This raises the following issue: policies designed for and motivated by persons with active lifestyles risk to fail if they do not succeed in meeting the needs for everyday life of those with inactive lifestyles.

working paper

Evaluation of the California Safe Routes to School Legislation: Urban Form Changes and Children's Active Transportation to School

Abstract

Walking or bicycling to school could contribute to children’s daily physical activity, but physical environment changes are often needed to improve the safety and convenience of walking and cycling routes. The California Safe Routes to School (SR2S) legislation provided competitive funds for construction projects such as sidewalks, traffic lights, pedestrian crossing improvements, and bicycle paths.

Phd Dissertation

Electronic waste management in California : consumer attitudes toward recycling, advanced recycling fees, "green" electronics, and willingness to pay for e-waste recycling

Publication Date

June 29, 2006

Author(s)

Areas of Expertise

Phd Dissertation

Modeling individual route choice with automated real -time vehicle trip histories

Abstract

Collecting rich individual trip data at an individual level has long been viewed as a hard task and has become a bottleneck in modeling and calibrating travel behavior models since traditional survey methods are both costly and time-consuming. New technologies make such data a possibility and thus there is a need for frameworks that model individual behavior in real-time using such data. Such modeling will find use in a variety of real-time network optimization and prediction schemes. This dissertation describes the details of plausible behavioral modeling of this kind, and develops new data structures that are needed both for handling the network combinatorics in the analysis and in the data storage. The work is presented in the context of a new technology we propose called the Persistent Traffic Cookie (PTC) system which uses the short range wireless connection between vehicles and road side controllers to store authenticated, time-stamped node sequences on an onboard database. The dissertation makes the premise that traditional travel behavior models, including those based on disaggregate decision paradigms were developed primarily for application in aggregate level prediction and are thus not very applicable for an individual’s route choice prediction in real-time. A scheme that does not require variation of explanatory variables across the choice sets or variation in the individual’s decisions for calibration may be essential. Thus the dissertation developed models based on observed frequencies of decisions. The research also stresses the importance of path and sub-path notions in route choice decisions and provides appropriate data structures that enable modeling with such notions. Two methods that directly query the collected sequence data using efficient data structures based on the suffix tree and the suffix array schemes and node/edge transition probability model, are proposed to predict individual travels from trip diary database. A day-to-day PTC simulation framework with behavior components is proposed to generate consistent PTC data and implemented in Paramics microscopic traffic simulator. Day-to-day PTC simulations are carried out for two Paramics networks, including the Irvine Triangle network, which is a well-calibrated real world network. Various scenarios are created to test the sensitivities of the proposed prediction methods. The simulation results shows that it seems the prediction methods are robust with regard to the underlying behavior models, traffic conditions and tracking periods.

Phd Dissertation

Predicting activity types from GPS and GIS data.

Abstract

Current travel forecasting models have had limited sensitivity to policy decisions. One of the primary challenges with travel forecasting models (both experimental and those implemented) is limitations in the data. The primary data source, the daily travel diary, is limited in both accuracy and sample size. The daily travel diary has known problems with underreporting, time inaccuracies, respondent fatigue, and other human errors. Global positioning systems (GPS) have been recently used to supplement the daily travel diary. As GPS becomes more accurate, reliable, and cost effective, could it entirely replace the daily travel diary? A number of efforts have used GPS data for route choice studies and to supplement daily travel diaries by providing more accurate time data, and determining under-reporting rates. GPS is also used in computer assisted daily travel diaries, reminding respondents of activities they may have forgotten to report. GPS devices record times and locations of each activity and the trips between those activities. To use GPS data to replace the daily travel diary one need only predict the activity types. The goal of this research is to develop and test a model to predict activity types based solely on: (1) GPS data from devices placed on the individual’s vehicle or person, (2) Land use data, such as location type, expressed as GIS data, and (3) Demographic data for the individual and the household. This thesis summarizes models developed using discriminant analysis and classification/regression trees. The models predicted in which of 26 different activity types the individual participated. Accuracy for out of home activities for the best model was 63%. When combed with the activity of being at home (which can be accurately predicted if we know the individuals home location) an accuracy of 79% was achieved (72% if you consider that GPS data may miss as much as 10% of trips). Since travel diaries have been known to underreport trips by as much as 25%, GPS data with the model developed can be very competitive. It is even more appealing considering the time inaccuracies and human error associated with travel diaries.

Phd Dissertation

Real time mass transport vehicle routing problem: Hierarchical global optimization for large networks.

Publication Date

April 19, 2006

Author(s)

Abstract

This dissertation defines and studies a class of dynamic problems called the “Mass Transport Vehicle Routing Problem” (MTVRP) which is to efficiently route n vehicles in real time in a fast varying environment to pickup and deliver m passengers, where both n and m are large. The problem is very relevant to future transportation options involving large scale real-time routing of shared-ride fleet transit vehicles. Traditionally, dynamic routing solutions were found using static approximations for smaller-scale problems or using local heuristics for the larger-scale ones. Generally heuristics used for these types of problems do not consider global optimality. The main contribution of this research is the development of a hierarchical methodology to solve MTVRP in three stages which seeks global optimality. The first stage simplifies the network through an aggregated representation, which retains the main characteristics of the actual network and represents the transportation network realistically. The second stage solves a simplified static problem, called “Mass Transport Network Design Problem” (MTNDP). The output of stage 2 is a set of frequencies and paths used as an initial solution to the last stage of the process, called Local Mass Transport Vehicle Routing Problem (LMTVRP), where a local routing is performed. The thesis presents the proposed methodology, gives insights on each of the proposed stages, develops a general framework to use the proposed methodology to solve any VRP and presents an application through microsimulation for the city of Barcelona in Spain.