Peer Reviewed Publications
Abstract ↓
Cycling to work is uncommon in most areas of the US, but relatively common in a particular set of metros and neighbourhoods. Explanations for this spatial heterogeneity often focus on differences in local geography, with some areas being allegedly more suitable for cycling. I estimate the role of topography and climate in determining the share of a metro's workers who cycle to work and the probability a particular worker chooses to cycle. I combine a US wide data set of commute flows with detailed elevation and climate data. I find that climate and topography play essentially no role in explaining cycling mode share across metros. Across workers, the hilliness of a commuter's route is found to be statistically irrelevant to cycling mode choice.
Abstract ↓
Laws concerning marijuana have recently undergone liberalization in many North American markets. The changing legal environment has enabled the establishment of retail marijuana dispensaries. Local externalities generated by dispensaries may impact home values, particularly by influencing demand for the surrounding neighbourhood. Recent empirical evidence has found a positive effect of dispensaries on home values. I use unique data on 84 dispensaries and 62,000 repeat home transactions from Vancouver, Canada to estimate the effect of dispensaries on home prices. Historical Google Street View images are used to construct a longitudinal record of dispensary activity. I find no evidence that dispensaries increase local home values in Vancouver and some evidence of a negative price effect for homes located within 100 meters of a dispensary.
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The importance of substitution patterns between public transit and carsharing has been discussed in prior literature. This study provides empirical evidence of significant interaction between the two modes. On November 24, 2015 the public transit rail system in Vancouver, Canada experienced a significant service disruption due to an unforeseen mechanical failure. This study exploits this event as a natural experiment and investigates to what extent the city's largest carsharing service was utilized as a substitute. Extensive carsharing vehicle location data are used to examine how the carsharing network responded to the transit service disruption. Empirical results show a dramatic increase in the use of carsharing vehicles during the transit outage, particularly in areas close to affected transit stations. Through regression analysis, the quantity of vehicle trips accommodated by the carsharing system in response to the outage is estimated to be approximately 800. There is clear evidence of extemporaneous substitution between public transit and carsharing, suggesting the two modes act as parts of an integrated network.
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The choice to use bus transit over a rival mode of transportation is a consequence of many variables. The importance of bus service quality on mode share is often considered but rarely measured explicitly. This study presents a novel temporal data set of geolocated buses from New York City. The merger of locational vehicle data with public schedule data allows for the estimation of bus dependability across neighbourhoods. This study uses plausibly exogenous spatial variation in the introduction New York City’s Select Bus Service program to explore the relationship between the policy intervention, bus service quality and changes in commuter mode share. A propensity score matching procedure compares bus reliability and mode share in tracts that received Select Bus Service to a control group. A sizeable treatment effect is found. The policy intervention significantly increased service frequency and improved bus arrival reliability. Additionally, bus mode share amongst commuters in treatment neighbourhoods increased substantially. Select Bus Service was responsible for an increase in local bus mode share of 1.9 percentage points, with bus mode share in the median tract rising from 9.6% to 11.5%. Female commuters are found to be more responsive to the service improvements than males.
Abstract ↓
Carsharing programs have demonstrated a potential to significantly shift incentives with regard to private vehicle ownership. The advent of free-floating vehicle fleets has enabled providers to offer ubiquitous vehicle access in designated urban areas. The ability of users to choose where to drop off vehicles presents the possibility that the density of available vehicles in particular areas will be insufficient to supply a reasonable level of service to local residents. The current paper will use exclusive data on vehicle location from a free-floating carshare service that operates in ten U.S. cities. Analysis will relate the availability of vehicles to census tract demographics. Results show vehicles cluster in tracts that are disproportionately populated by residents who are educated, young, employed, and white. Carshare systems have received significant in-kind incentives from government to operate. The mobility benefits of free-floating carshare systems appear to accrue disproportionately to advantaged populations.
Abstract ↓
Expanding employment opportunities for citizens has become an increasingly central goal of public policy in the United States. Prior work has considered that the inability of households to spatially access jobs may be a driver of unemployment. The provision of public transportation provides a viable policy lever to increase the number of job opportunities available to households. Previous research has yielded mixed results regarding whether household location is an important factor in determining employment status. Several papers have identified mobility as a limiting factor for obtaining a job, particularly in regards to private vehicle ownership. The location of economically developed neighbourhoods and the citing of public transportation are conceivably codetermined, presenting an endogenous relationship. It is therefore unclear if public transportation access is actually contributing to neighbourhood job market outcomes. This paper will use the incidence of Hurricane Sandy striking New York City on 29 October 2012 and the resulting exogenous reduction in public transit access to particular neighbourhoods as a natural experiment to test for the effect of public transportation on employment outcomes. This study identifies a significant causal effect linking public transportation access to neighbourhood unemployment rates, particularly amongst subgroups dependent on public transit.
Working Papers
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The Local Labour Market Effects of Light Rail Transit
Awards: Best paper by a graduate student, 2018 Transportation Research Forum Runner-up for best overall paper, 2018 Canadian Transportation Research Forum |
Abstract ↓
US cities have made large investments in light rail transit in recent years. Arguments in favour of light rail construction typically focus on enhancing workers' access to job opportunities. I analyse the labour market effects of light rail construction in four US metropolitan areas between 2000 and 2013. I propose a new instrumental variable to overcome endogeneity in transit station location. An inclination among transportation planners to extend light rail to the airport introduces a source of quasi-random neighbourhood assignment, enabling causal identification of neighbourhood effects. I find that light rail improves local employment outcomes. Local amenities cause workers to sort within a city, meaning that neighbourhood effects could be the result of endogenous sorting. To estimate distributional consequences and welfare effects, I propose and estimate a structural model of neighbourhood choice. The model is estimated with novel Google navigation data. I find that light rail systems fail to raise aggregate metropolitan employment because induced rent increases repel low skilled workers, displacing them to inaccessible locations.
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Pedestrian Deaths and Large Vehicles
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Abstract ↓
Traffic fatalities in the US have been rising among pedestrians even as they fall among motorists. Contemporaneously, the US has undergone a significant shift in consumer preferences for motor vehicles, with larger Sport Utility Vehicles comprising an increased market share. Larger vehicles may pose a risk to pedestrians, increasing the severity of collisions. I use data covering all fatal vehicle collisions in the US and exploit heterogeneity in changing vehicle fleets across metros for identification. Between 2000 and 2018, I estimate that replacing the growth in Sport Utility Vehicles with cars would have averted 900 pedestrian deaths. Vehicle body type affects pedestrian safety more than vehicle weight and the largest Sport Utility Vehicles appear particularly culpable for pedestrian deaths.
w. Xiuming (Audrey) Dong
Abstract ↓
Many North American jurisdictions have legalized the operation of recreational marijuana dispensaries. A common concern regarding dispensaries is that they may contribute to local crime. Identifying the effect of dispensaries on crime has been confounded by the spatial endogeneity of dispensary locations. We analyze dispensaries and crime in Pierce County, Washington. Washington allocated dispensary licences through a lottery, providing a natural experiment to estimate the causal effect of dispensaries on crime. We combine lottery data with detailed geocoded crime data. Results indicate that dispensaries have no effect on local crime.
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Sea Level Rise and Housing Prices: Evidence from Long Island
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Abstract ↓
Global sea level rise is a known consequence of climate change. As predictions of sea level rise have grown in magnitude and certainty, coastal real estate assets face an increasing climate risk. I use a complete data set of repeated home sales from Long Island in New York State to estimate the appreciation discount caused by the threat of sea level rise. Between 2000 and 2017, I find that exposure to future sea level rise among single family homes had no impact on price appreciation. However, multifamily properties exposed to future sea level rise had annual price appreciation 1.4 percentage points below unexposed properties. I examine the role of investor sophistication to explain this discrepancy.
Other Publications
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Mobility, Economic Opportunity and New York City Neighborhoods
(w. Kaufman, Moss and Hernandez) 2015, The Rudin Center. |