Cynthia Chen

University of Washington Seattle | UW · Department of Civil and Environmental Engineering

Networks can evolve even on a short-term basis. This phenomenon is well understood by network scientists, but receive little attention in empirical literature involving real-world networks. On one hand, this is due to the deceitfully fixed topology of some networks such as many physical infrastructures, whose evolution is often deemed unlikely to o...

The last decade has witnessed very active development in two broad, but separate fields, both involving understanding and modeling of how individuals move in time and space (hereafter called “travel behavior analysis” or “human mobility analysis”). One field comprises transportation researchers who have been working in the field for decades and the...

The practice of left-turn phasing selection (permissive, protected-only, or both) varies from one locality to another. The literature evidence on this issue is equally mixed and insufficient. In this study, we evaluate the safety impacts of changing left-turn signal phasing from permissive to protected/permissive or protected-only at 68 intersectio...

This paper contributes to the understanding of disasters from the perspective of social media activities. We develop a measure based on Twitter activities that can be used to quantify the evolution of disasters and thus demonstrate temporal–spatial patterns of Twitter activities particularly near the coastline and in large urban areas during Hurric...

This study examines the connection between the built environment, perceived safety from crime and walking behaviour by conducting a travel survey in King County, Washington State, U.S. and employing a two-stage least squares model. We seek to answer two research questions: how does the built environment affect perceived safety from crime and walkin...

The effects of fuel price on travel demand for different income groups reveal the choices and constraints they are faced with. The first purpose of this study is to understand these underlying choices and constraints by examining the variation of fuel price elasticity of vehicle miles travelled (VMT) across income groups. On the other hand, the reb...

Walking, the simplest form of transportation has many benefits for pedestrians and the society. Yet, pedestrians are a vulnerable group of people and safety concerns are a significant barrier in one's decision to walk. Multiple signal related pedestrian countermeasures have been proposed to promote pedestrian safety. Although the safety impacts of...

This paper provides a large-scale, rigorous evaluation of traffic calming projects in one U. S. city. The study area is New York City, which treated 391 streets with speed tables between 1996 and 2003. On the basis of crash frequencies for 5 years before treatment and 5 years after for treated streets and well-matched comparison streets, no evidenc...

In this paper, we investigate the spatial extent of the housing search. Using the concepts of mental map and awareness space, we argue that search space is affected by households' preferences, what is available on the housing market, and the use of information channels as well as their interactions. We hypothesize that households whose members disa...

Traffic fatalities and injuries constitute a major global public health problem and the United States has fallen behind other developed countries in traffic safety. Yet, New York City stands out as a traffic safety model in the nation with its low fatality rate and its significant reductions in various types of crashes. This study develops a safety...

To understand the evolution of a disaster, we propose a Framework for Assessing Crisis in a System Environment (FACSE). FACSE is set in a multi-system environment, containing the human system as well as the various natural and technological systems that interact with people. We take a lifecycle perspective, via which we quantify rhythms of life exh...

Pedestrians and cyclists are a vulnerable group of road users. Immigrants are disproportionally represented in pedestrian and cyclist crashes. We postulate that the mismatch in safety culture between countries of their origin and the U.S.A. contribute to their vulnerability in pedestrian and cyclist crashes. Over time, the differences may disappear...

We evaluated the effects of on-street bicycle lanes installed prior to 2007 on different categories of crashes (total crashes, bicyclist crashes, pedestrian crashes, multiple-vehicle crashes, and injurious or fatal crashes) occurring on roadway segments and at intersections in New York City. We used generalized estimating equation methodology to co...

We propose a decomposition of residential self-selection by understanding the process of its formation. We take a life-course perspective and postulate that locations experienced early in life can have a lasting effect on our locational preferences later in life. In other words, what was experienced spatially is a key factor contributing to our res...

This study seeks to determine the relative impacts of various factors in affecting ridership, to quantify their short-run and long-run effects, and to test the symmetry in ridership in response to rises and falls in gasoline price and transit fare. The results show that the effect of gasoline price, albeit small, is significant, extends over a year...

The idea of using transit-oriented development (TOD) in reducing automobile dependency and improving the sustainability of transportation activities has gained wider support in recent years. Research findings have shown that residents living in TOD neighborhood used transit more frequently than people having similar socio-economic characteristics b...

The combination of increasing challenges in administering household travel surveys and advances in global positioning systems (GPS)/geographic information systems (GIS) technologies motivated this project. It tests the feasibility of using a passive travel data collection methodology in a complex urban environment, by developing GIS algorithms to a...

Many types of traffic data are often recorded as (Main street, From street, To street) triples. All the segments between the intersection pairs of (Main street, From street) and (Main street, To street) need to be geocoded, with additional directional constraints. We term this new type of geocoding task as segment-type gecoding in contrast with cla...

Most of the existing literature on residential location choice is cross-sectional and assumes no history effect in people’s residential location preferences. However, human beings are constantly adjusting themselves to the local environment and thus it seems reasonable to assume that preferences are formed over time. We hypothesize a historical dep...

We study the diurnal pattern of subway ridership in New York City. Our study complements the existing line of research that looks at the dynamics of a place by studying the socio-demographics of its visitor population. It also points out an important omission in ridership research on the time of day dimension. The study results identify five main c...

In this paper, we used the 10-wave Puget Sound Panel Dataset to investigate the response lag of a significant change in discretionary time use. In particular, we want to quantify the relative magnitude of the following factors: the built environment, family and social obligations, temporal constraints, or a psychological delay factor (people delay...

The literature for residential location choice is deficient in two aspects. First, many studies model location choice as a static choice, with no memory of the past. Second, current understanding of household trade-offs between attributes is limited. These two issues are addressed by developing and estimating a residential location model that accou...

This study uses the social capital concept to explain geographical variation in public library use. Applying Putnam's social capital theory, we examine how social capital in three New York City neighbourhoods affects usage of local branch libraries. A survey was conducted to understand differences in public library use and social capital in the nei...

There have been a number of studies of the effectiveness of vehicle scrappage programs, which offer incentives to accelerated scrappage of older vehicles often thought to be high emitters. These programs are voluntary and aimed at replacement of household vehicles. In contrast, there is a gap in knowledge related to the emissions benefits of govern...

Density is a key component in the recent surge of mixed-use neighborhood developments. Empirical research has shown an inconsistent picture on the impact of density. In particular, it is unclear whether it is the density or the variables that go long with density that affect people’s travel behavior. Many existing studies on density neglect confoun...

Past studies have shown that initial pavement roughness greatly affects future pavement roughness and roughness progression rate. Initial pavement roughness is also an important input to the roughness prediction model in mechanistic-empirical design guide. This study analyzed the design and construction factors affecting initial pavement roughness....

Homemakers, unlike employed people who have jobs and unemployed people who are seeking jobs, are a special group who do not have to spend time working out of the home, commuting to work, or looking for a job. Given that a regular job typically takes 9h (This includes an assumed half-hour one-way commute time.) a day, the discretion to allocate thei...

This annual special issue of "Transportation" comprises selected papers presented at the Annual Meeting of the Transportation Research Board (TRB) in January 2007. These papers all address the interrelationship between the built environment and travel behavior. Specifically, they provide insight into several important aspects of this topic, includi...

According to the US Federal Highway Administration (FHWA), the number of publicly owned vehicles in the USA reached 3 913 999 in 2003. In order to maintain a stable vehicle fleet, government agencies must repeatedly make vehicle scrap-page decisions because older vehicles must first retire to make room for newer vehicles. Typically, these decisions...

In air quality modeling, vehicle survival rates, also frequently referred to as retention rates, are very important for modeling mobile emissions inventories. The vehicle survival rate determines how many vehicles in the current fleet will survive to a future year, which, when added to new vehicle sales, provides a vehicle population forecast for a...

This paper focuses on the tradeoff in time allocation between maintenance activities/travel and discretionary activities/travel. With the recognition that people are not completely free to allocate their time between activities and travel, we propose a linear constraint in time allocation between activities and travel, which indicates a minimum amo...

This paper summarizes and analyses findings from more than two dozen aggregate and disaggregate studies of travel time (and sometimes money) expenditures, exploring the question of the existence of a constant travel time budget. We conclude (with prior researchers) that travel time expenditures are not constant except, perhaps, at the most aggregat...

Utility maximization is widely used to model individuals’ activity scheduling and rescheduling behavior. Utility maximization is based on the assumption that the modeled behavior is the result of a reasoned decision. An alternative to a planned behavior is habitual behavior, whose execution process has become automatic due to its repeated performan...

The development and initial validation results of a micro-simulator for the generation of daily activity-travel patterns are presented in this paper. The simulator assumes a sequential history and time-of-day dependent structure. Its components are developed based on a decomposition of a daily activity-travel pattern into components to which certai...

With limited information and computational capability, travelers (especially tourists) often fail to develop an itinerary that best suits their needs. A computer software program called Itinerary Planner was developed to help travelers find a suitable itinerary by generating alternative travel itineraries. Compared to existing trip planners, the It...

It is important that our travel be organized in an efficient way. One way to achieve this is to provide travelers with a trip planner that produces efficient travel itineraries for them. It is desired that a trip planner possess the following features in order to be useful: be able to handle multiple destinations, multiple constraints, and multiple...

Stated Choice models expand the ability of transportation planners to forecast future trends. The Stated Choice approach can forecast demand for new services or policies. However, Stated Choice models are subject to a range of experimental error not found within Revealed Preference (RP) designs. Primary among the concerns facing researchers is the...

Multinomial logit destination choice models are developed and the following hypotheses are examined: (a) time of day affects destination choice behavior, (b) the duration of stay at the destination affects destination choice, and (c) home location affects non-home-based destination choice. The statistical results offer strong evidence in support of...

This paper describes the development and application of an activity-based microsimulation model system capable of simulating changes in individual travel patterns in response to a transportation control measure. A unique activity-based time use survey was conducted to obtain information on people's activity and travel patterns and their likely beha...

Discrete choice models have expanded the ability of tranportation planners to forecast future trends. Where new service or policies are proposed, the stated-choice approach can provide an objective basis for forecasts. Stated-chioce models are subject to a range of experimental errors not found in revealed-preference designs. Primary among the conc...

Microsimulation approaches to travel demand forecasting are gaining increased attention because of their ability to replicate the multitude of factors underlying individual travel behavior. The implementation of microsimulation approaches usually entails the generation of synthetic households and their associated activity-travel patterns to achieve...