Assessment of California MPO Travel Demand Forecasting Models

The goal of this project was to assess the capabilities of the travel demand forecasting models (TDMs) used by California’s metropolitan planning organizations (MPOs) with respect to forecasting the increase in vehicle miles of travel induced by highway capacity expansion. An expert panel assisted with the development of review questions to be used in assessing the models. These questions were used to assess each of the models currently used by the eighteen MPOs in California based on information found in readily available documents. The assessment found that seven MPOs are using activity-basedmodels, nine are using four-step, trip-based models, and two are using hybrid models. In general, the activity-based models do a better job of capturing possible induced travel effects. Only one model includes explicit feedback between the transportation system and land use patterns. The readily-available documentation of travel demand forecasting models in California is insufficient for fully understanding the variables included in each model component and the structure of feedbacks between components of the models.View the NCST Project Webpag

Travel Demand Modeling and the Assessment of Environmental Impacts: A Literature Review

The purpose of this literature review is to assess what is currently known about the ability of travel demand forecasting models (TDMs) to provide accurate forecasts for different types of transportation plans and projects with respect to different outcome measures of interest. The role of TDMs in assessing the implications of highway expansions for vehicle miles of travel (VMT) and greenhouse gas (GHG) emissions is of particular interest given the current regulatory context. Relevant studies for this review were found using a variety of search terms in the Transport Research International Documentation (TRID) database and Google Scholar. The report reviewed the available studies with respect to the themes of limitations of the models, validity testing and sensitivity testing, and VMT forecasting. View the NCST Project Webpag

Exploring the Induced Travel Effects from Minor Arterials, Auxiliary Lanes, and Interchanges

A robust body of empirical research demonstrates that as roadway supply increases, vehicle miles traveled (VMT) generally does, too. The evidence is particularly strong with respect to major roadways, like interstate highways (class 1), other freeways and expressways (class 2), and principal arterials (class 3). However, previous literature reviews have found limited empirical evidence as to the relative magnitude of the induced travel effect of expanding minor arterials, collector streets, and local roads. Previous reviews have similarly not reported empirical research on the induced travel effects of other types of roadway facilities, such as auxiliary lanes, ramps, or other types of interchanges. In this project, the authorsconducted a systematic literature review on the induced travel effects of minor arterials, auxiliary lanes, and interchanges (including simple on/off ramps). The authors found that the empirical literature remains limited with respect to auxiliary lanes and interchanges. They found eight studies that include minor arterials in their empirical estimates of induced travel, which collectively indicate that the induced travel elasticity for class 4 minor arterials could be similar to that of class 1-3 facilities. However, none of the studies isolated the induced travel effect from minor arterials specifically. Going forward, the report suggests avenues for future research to help close these research gaps. For example, the authors recommend using case studies of individual roadway expansions to better understand the induced travel effects specific to ramps, interchanges, minor arterials, and auxiliary lanes within specific contexts, especially where larger studies (across multiple facilities, geographies, etc.) have not yet been done. View the NCST Project Webpag

Exploring the Equity Effects of VMT Mitigation Measures

In 2018, pursuant to Senate Bill (SB) 743 (2013), the Governor’s Office of Planning and Research (OPR) and the California Natural Resources Agency promulgated regulations and technical guidance that eliminated automobile level of service (LOS) as a transportation impact metric for land development projects under the California Environmental Quality Act (CEQA), and replaced it with Vehicle Miles Traveled (VMT). The authors investigated the equity effects of VMT mitigation measures and developed a framework for evaluating those effects at the project level. The authors then applied the framework to two highway expansion case studies in California. They found that most VMT mitigation would be implemented at least partially within the project impact areas, as well as some disadvantaged communities, but would generally benefit communities outside of the project area, too. Most of the proposed mitigation measures would not displace existing residences or businesses or pose a significant risk of gentrification. Many of the measures showed substantial potential to improve accessibility to jobs, though less potential to improve accessibility to grocery stores. Community engagement and empowerment was harder to gauge. Overall, the five-part framework can provide a first-cut assessment of the equity effects of VMT mitigation measures during the environmental review phase of VMT-generating projects, like roadway expansions.View the NCST Project Webpag

The Effects of Commuter Rail on Population Deconcentration and Commuting: A Salt Lake City Case Study

All transportation systems have the ability to transform human settlement patterns, which can affect a range of social, economic and environmental issues. Considering investments in rail infrastructure have increased in recent decades (Bureau of Transportation Statistics, 2007; Israel & Cohen-Blankshtain, 2010), it is important for planners and researchers to understand how these rail systems influence land use, metropolitan development patterns, and population migration. The following paragraphs summarize the studies and their findings. The Effects of Commuter Rail Establishment on the Relationships between the Built Environment, Travel Behavior, and Residential Self- Selection (RSS): To help regional and transportation planners better understand the role that commuter rail plays in directing intra-regional development, this chapter provides a longitudinal investigation of the influence of commuter rail on surrounding neighborhoods’ RSS, travel behavior and the built environment. We first analyze the role of commuter rail establishment in influencing change in neighborhood-level demographics, housing and economics (signs of RSS), and travel behavior. Second, we compare surveyed commuter rail riders to residents of the commuter rail stations’ host and neighboring areas. The results indicate that the development of commuter rail does not alter the host tracts in any of the characteristics observed, but rather suppresses population growth in neighboring tracts. Paired with direct evidence from a commuter rail user survey, we conclude that the use of commuter rail is more likely influenced by the built environment than by RSS. The Effects of Commuter Rail Establishment on Population Deconcentration: Research to date has not established the efficacy of commuter rail systems in attracting migrants most likely to use such an amenity. Through the application of a modified population deconcentration model, this chapter finds that the provision of a commuter rail station significantly increases neighborhood-level out-commuting and gross migration, which signals success in attracting migrants requiring commuting infrastructure. These findings also signal that commuter rail encourages regional population deconcentration, but the evidence is insufficient to form a conclusion and the evidence from Chapters 2 and 4 signal otherwise. Developing an Agent-Based Model (ABM) For Estimation of Land Use Changes around Commuter Rail Stations over Time: This chapter improves the understanding of commuter rails’ effect on future land use changes through spatial interaction modeling. In particular, we develop an innovative agent-based model (ABM) that allows us to estimate and visualize the probability of land use changes per parcel based on proximity to commuter rail stations, freeway exits, and the region’s central business district. Briefly, this chapter concludes that the development of a commuter rail station is statistically significantly associated with decreases in single-family residential land use near the station, which is met by increases in multifamily and mixed-use development. The spatial effects of stations on individual land uses vary by land use type, and no generalizable area of influence could be established. This report points to potential future research, as well as implications for planning practitioners

Commuter Rail Transit and Economic Development

Commuter rail transit (CRT) is a form of rail passenger service connecting downtowns and other major activity centers with suburban commuter towns and beyond. Between 1834 and 1973, only three public CRT systems were built in the U.S. serving New York, Chicago and then Boston. There are now 25 such systems. Modern CRT systems aim to expand economic development in metropolitan areas. But do they? This paper evaluates the economic development performance of five modern CRT systems. The authors find that several economic sectors perform well within 0.50 miles of CRT stations. The authors offer planning and policy implications

The changing role of employment status in marriage formation among young Korean adults

Background: Despite a persistent decline in Korea's marriage rates over the past three decades, there is a striking lack of research on the transition to marriage among young Koreans. Similarly, few studies have examined how economic determinants have evolved over the past several decades, even as the Korean social and socioeconomic structure has undergone substantial transformation. Methods: This paper examines changes over time in the determinants of marriage formation in Korea, using employment history data from the Korean Labor and Income Panel Study (KLIPS) on three cohorts of young adults born in the 1950s‒1970s. Results: Results indicate that, for women, the marital implications of being employed reversed over the three decades examined. While working decreased the odds of getting married for women born in the 1950s, it had no statistically significant effect for those born in the 1960s, and it strongly increased the odds of marriage for the most recent (1970s) cohort of women. For their part, men's employment not only continued to positively predict getting married over the three decades, but its impact became stronger with each cohort, so that a man's odds of transition to first marriage was most strongly tied to his employment status for those born in the 1970s, as compared to earlier cohorts. Contribution: This study contributes to the literature by addressing the relationship between marriage timing and economic resources using more direct measures, examining the association between mandatory military service and marriage formation, and testing if determinants of marriage timing may evolve over time in Korea