Bock, M., B. Humphreys, and D. Paranavitana
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Traffic congestion represents a ubiquitous and serious urban problem around the world. Policymakers frequently enact expensive policies like highway lane expansion, expansion of public transportation, and driving restrictions based on license plates to combat traffic congestion. Adaptive Traffic Control Systems (ATCS) that dynamically alter the red/green cycle timing based on real-time traffic conditions represent an increasingly popular, low-cost approach to reducing congestion. We analyze the impact of the installation of 4,700 ATCS signals in Los Angeles City in 2013 on local traffic congestion using the synthetic control method. Results based on panel data from 96 California cities over the period 2010-2017 show that the ATCS signals did not reduce congestion in Los Angeles, but they did slow the increase in congestion relative to the increase in the synthetic unit, suggesting that ATCS signals impact traffic congestion but cannot effectively reduce it.
M. Bock
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The effects of high occupancy vehicle (HOV) lanes studied from a causal perspective have been minimal in the economics literature. Knowing the impacts of these types of infrastructure projects is beneficial in terms of public policy and resource allocation. Using an instrumental variable (IV) approach to overcome the endogeneity problems associated with HOV lane location selection, this study aims to uncover the impacts of HOV lanes on commuters' time spent going to and coming home from work in California. This paper finds that both having HOV lanes in workplace counties and living closer to HOV lanes cause increased commute times to and from work for commuters, lending credence to earlier works on road construction and traffic outcomes citing induced demand from increased road construction (Duranton and Turner, 2011)
Blemings, B., M. Bock, and A. Scarcioffolo
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While it has long been recognized that agricultural production comes with costs and benefits, its effects on transportation have remained under-studied. This paper estimates the effect of pork slaughterhouses on truck traffic and the subsequent consequences such as traffic crashes, road roughness, and auto repair employment. To recover causal estimates using two stage least squares, we exploit historic hog population as quasi-random variation in current pork slaughterhouse locations. We document historic hog data using a combination of historical data sources - recorded Census numbers from 1945 and maps which we process to produce data as far back as 1840. Using two-stage least squares, we find a one unit increase in slaughter volume increases truck traffic by 17.6%, fatal traffic crashes by 20.9%, and auto repair employment by 77%. Furthermore, estimates suggest that 95% of slaughterhouse volume on crashes is mediated by truck traffic and 100% of the effect on auto repair is due to trucks. These estimates are important for quantitatively assessing the optimal tax to address negative truck externalities resulting from slaughter and other industries.
M. Bock
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WVU best graduate student paper
NARSC graduate student paper competition: 1st runner up
SEA graduate student session participant
A growing literature aims to uncover the causal link between highways and economic activity. However, specific attention to federally funded rural roads and highways is sparse given implicit endogeneity concerns about road placement decisions for the sake of rural development and market exposure. This study examines the impact of the Appalachian Development Highway System (ADHS), one of the largest and most expensive federal infrastructure projects in the United States, on mortality outcomes in the region. Instrumental variable (IV) results suggest ADHS construction significantly reduced travel-time-sensitive mortality rates, such as heart disease and hypertension, in earlier decades of the sample. IV results also suggest the ADHS may be associated with increased mortality rates, notably accidents, in later decades of the sample. The additional cost caused by the ADHS in terms of mortality is estimated to be $24.2 billion dollars over the length of the sample. However, benefits such as improved travel times, employment, and income increases outweigh these costs.
Bock, M., A. Cardazzi, J.D. Hall, and C. Lennon
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