Guangqing Chi

Can Knowledge Improve Population Forecasts at Subcounty Levels

Recent developments in urban and regional planning require more accurate population forecasts at subcounty levels, as well as a consideration of interactions among population growth, traffic flow, land use, and environmental impacts. However, the extrapolation methods, currently the most often used demographic forecasting techniques for subcounty areas, cannot meet the demand. This study tests a knowledge-based regression approach, which has been successfully used for forecasts at the national level, for subcounty population forecasting. In particular, this study applies four regression models that incorporate demographic characteristics, socioeconomic conditions, transportation accessibility, natural amenities, and land development to examine the population change since 1970 and to prepare the 1990-based forecast of year 2000 population at the minor civil division level in Wisconsin. The findings indicate that this approach does not outperform the extrapolation projections. Although the regression methods produce more precise projections, the least biased projections are often generated by one of the extrapolation techniques. The performance of the knowledge-based regression methods is discounted at subcounty levels by temporal instability and the scale effect. The regression coefficients exhibit a statistically significant level of temporal instability across the estimation and projection periods and tend to change more rapidly at finer geographic scales.

Gasoline prices and traffic safety in Mississippi.

PROBLEM Limited literature suggests that gasoline prices have substantial effects on reducing fatal crashes. However, the literature focuses only on fatal crashes and does not examine the effects on all traffic crashes. METHODS Mississippi traffic crash data from April 2004-December 2008 from the Mississippi Highway Patrol and regular-grade unleaded gasoline price data from the Energy Information Administration of the U.S. Department of Energy were used to investigate the effects of gasoline prices on traffic safety by age, gender, and race. RESULTS Gasoline prices have both short-term and intermediate-term effects on reducing total traffic crashes and crashes of females, whites, and blacks. The intermediate-term effects are generally stronger than the short-term effects. Gasoline prices also have short-term effects on reducing crashes of younger drivers and intermediate-term effects on older drivers and male drivers. IMPACT ON INDUSTRY Higher gasoline taxes reduce traffic crashes and may result in additional societal benefits.

Rethinking Highway Effects on Population Change

Little systematic work has been undertaken to explain highway impacts on population change. In this study, the authors review the literature in regional economics and demographics in an attempt to shed light on the mechanisms by which investments in highway infrastructure influence population change. First, they categorize the indirect causal paths by which highways influence population change at the county and municipal levels. Then they propose a spatio-temporal approach to revisit highway effects on population change from the stage of highway development and areal characteristics specifically. Finally, it is concluded that at the county and municipal levels, the effect of highways on population change varies from preconstruction to postconstruction periods and across urban, suburban, and rural areas.

Gasoline prices and their relationship to drunk-driving crashes

This study investigates the relationship between changing gasoline prices and drunk-driving crashes. Specifically, we examine the effects of gasoline prices on drunk-driving crashes in Mississippi by several crash types and demographic groups at the monthly level from 2004 to 2008, a period experiencing great fluctuation in gasoline prices. An exploratory visualization by graphs shows that higher gasoline prices are generally associated with fewer drunk-driving crashes. Higher gasoline prices depress drunk-driving crashes among young and adult drivers, among male and female drivers, and among white and black drivers. Results from negative binomial regression models show that when gas prices are higher, there are fewer drunk-driving crashes, particularly among property-damage-only crashes. When alcohol consumption levels are higher, there are more drunk-driving crashes, particularly fatal and injury crashes. The effects of gasoline prices and alcohol consumption are stronger on drunk-driving crashes than on all crashes. The findings do not vary much across different demographic groups. Overall, gasoline prices have greater effects on less severe crashes and alcohol consumption has greater effects on more severe crashes.

Highways and Population Change.

In this paper we return to an issue often discussed in the literature regarding the relationship between highway expansion and population change. Typically it simply is assumed that this relationship is well established and understood. We argue, following a thorough review of the relevant literature, that the notion that highway expansion leads to increased population growth in the vicinity of the improved

Land Developability: Developing an Index of Land Use and Development for Population Research

Abstract Please click here to download the map associated with this article. This research proposes an approach for linking land use and development to population data by using the Model Builder function of ArcGIS. The layers of land use and development are aggregated into a single raster layer representing undevelopable lands. The layer of undevelopable lands in pixels is then aggregated to political or geographical areas from which a Developability Index representing the proportion of lands available for development can be derived. The index can then be linked to population data for demographic research. For demonstration purposes, the proposed approach is used to generate a Land Developability Index for all minor civil divisions of Wisconsin, USA, in 2001. This approach and the generated land developability are useful for studying the relationship between land use and development and population dynamics based on political or geographical areas.

Gasoline Prices and Traffic Crashes in Alabama, 1999–2009

Objective: The price of gasoline has been found to be negatively associated with traffic crashes in a limited number of studies. However, most of the studies have focused either on fatal crashes only or on all crashes but measured over a very short time period. In this study, we examine gasoline price effects on all traffic crashes by demographic groups in the state of Alabama from 1999 to 2009. Methods: Using negative binomial regression techniques to examine monthly data from 1999 to 2009 in the state of Alabama, we estimate the effects of changes in gasoline price on changes in automobile crashes. We also examine how these effects differ by age group (16–20, 21–25, 26–30, 31–64, and 65+), gender (male and female), and race/ethnicity (non-Hispanic white, non-Hispanic black, and Hispanic). Results: The results show that gasoline prices have both short-term and long-term effects on reducing total traffic crashes and crashes of each age, gender, and race/ethnicity group (except Hispanic due to data limitations). The short-term and long-term effects are not statistically different for each individual demographic group. Gasoline prices have a stronger effect in reducing crashes involving drivers aged 16 to 20 than crashes involving drivers aged 31 to 64 and 65+ in the short term; the effects, however, are not statistically different across other demographic groups. Conclusions: Although gasoline price increases are not favored, our findings show that gasoline price increases (or decreases) are associated with reductions (or increases) in the incidence of traffic crashes. If gasoline prices had remained at the 1999 level of

Highway Expansion Effects on Urban Racial Redistribution in the Post—Civil Rights Period

1.41 from 1999 to 2009, applying the estimated elasticities would result in a predicted increase in total crashes of 169,492 (or 11.3%) from the actual number of crashes. If decision makers wish to reduce traffic crashes, increasing gasoline taxes is a possible option—however, doing so would increase travel costs and lead to equity concerns. These findings may help to shape transportation safety planning and policy making.

Safer Roads Owing to Higher Gasoline Prices: How Long It Takes.

A limited number of historical case studies document that highway construction produced significant consequences on racial relationships and redistribution in the early and mid-20th century. Howev er, little is known about how the expansion of an existing highway system influences urban racial redistribution after the legal bases for social and env ironmental justice in highway construction were established. This research uses census data for 1970, 1980, 1990, and 2000 to examine the role that highway expansion plays in affecting the redistribution of Blacks and Hispanics at the census tract lev el within the Milwaukee-Waukesha-West Allis metropolitan area of Wisconsin. The results indicate that the concentration of Blacks and Hispanics in neighborhoods in close proximity to highways that were expanded between 1965 and 1970 increased substantially between 1970 and 2000. Highway expansion promotes Black growth in nearby neighborhoods through its role as an amenity by prov iding easy access to the transportation network. Highway expansion also promotes Hispanic growth but through its role as a disamenity by decreasing housing prices in immediate neighborhoods. The results hav e important policy implications for addressing the issue of racial relationships in urban America.

Measuring Public School Competition from Private Schools: A Gravity-Based Index

OBJECTIVES We investigated how much time passes before gasoline price changes affect traffic crashes. METHODS We systematically examined 2004 to 2012 Mississippi traffic crash data by age, gender, and race. Control variables were unemployment rate, seat belt use, alcohol consumption, climate, and temporal and seasonal variations. RESULTS We found a positive association between higher gasoline prices and safer roads. Overall, gasoline prices affected crashes 9 to 10 months after a price change. This finding was generally consistent across age, gender, and race, with some exceptions. For those aged 16 to 19 years, gasoline price increases had an immediate (although statistically weak) effect and a lagged effect, but crashes involving those aged 25 to 34 years was seemingly unaffected by price changes. For older individuals (≥ 75 years), the lagged effect was stronger and lasted longer than did that of other age groups. CONCLUSIONS The results have important health policy implications for using gasoline prices and taxes to improve traffic safety.