Peer Reviewed Publications
The Impact of Recreational Marijuana Dispensaries on Crime: Evidence from a Lottery Experiment
w. Xiuming (Audrey) Dong
Shared micromobility services have undergone rapid growth in cities throughout the world, including expansions in bike sharing and e-scooter sharing services. Shared micromobility provides a potential complement to public transit by accommodating first and last-mile trips. I analyze detailed data on shared, dockless bikes and e-scooters from Seattle, Washington. I find micromobility vehicles cluster near Seattle's rail transit stations. During the study period, Seattle expanded its rail system into a new section of the city. I use the system expansion as a natural experiment to provide evidence of complementarity between shared micromobility and public transit. Using a difference-in-difference strategy I find that, after a new light rail station opened, the flow of new micromobility vehicles increased significantly within a five minute walking radius of the station. I provide causal evidence that local rail transit increases the use of dockless micromobility vehicles.
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. The repeat sale methodology allows for time-invariant, unobserved property characteristics to be controlled for. Between 2000 and 2017, I find that residential properties that were exposed to future sea level rise experienced an annual price appreciation rate of roughly one percentage point below unexposed properties. I provide numerous robustness checks to confirm this result. I also find evidence of demand spillovers by estimating an appreciation premium for properties that are near the coast but are relatively safe from sea level rise.
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.
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 in- creased 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 2019, I estimate that replacing the growth in Sport Utility Vehicles with cars would have averted 1,100 pedestrian deaths. I find no evidence that the shift towards larger vehicles improved aggregate motorist safety.
Many US cities have made large investments in light rail transit in order to improve commuting networks. I analyse the labour market effects of light rail in four US metros. I propose a new instrumental variable to overcome endogeneity in transit station location, enabling causal identification of neighbourhood effects. Light rail stations are found to drastically improve employment outcomes in the surrounding neighbourhood. To incorporate endogenous sorting by workers, I estimate a structural neighbourhood choice model. Light rail systems tend to raise rents in accessible locations, displacing lower skilled workers to isolated neighbourhoods, which reduces aggregate metropolitan employment in equilibrium.
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.
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.
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.
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.
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.
The Impact of Recreational Marijuana Dispensaries on Crime: Evidence from a Lottery Experiment
w. Xiuming (Audrey) Dong
Many North American jurisdictions have legalized the operation of recreational marijuana dispensaries. A common concern is that dispensaries may contribute to local crime. Identifying the effect of dispensaries on crime is confounded by the spatial endogeneity of dispensary locations. Washington state allocated dispensary licenses through a lottery, providing a natural experiment to estimate the causal effect of dispensaries on crime. Combining lottery data with detailed geocoded crime data, we estimate that the presence of a dispensary has no impact on average local crime rates. However, within low-income neighborhoods, we find an increase in property crime adjacent to new dispensaries.
Restrictions on housing supply have contributed to a rapid increase in home prices and rents in many large cities. Incumbent homeowners may benefit financially from rising prices, while renters are harmed. Incumbent residents may also resist new local housing due to local congestion externalities. Supply restrictions are often implemented by city councils at the behest of their constituents. We analyze city council bills from Toronto, Canada spanning 2009 to 2020. A machine learning approach identifies bills related to housing supply. We link housing bills, councillor voting behaviour and local demographic information. We find that representing more homeowners causes a councillor to oppose more housing bills. Councillors are significantly more likely to oppose large housing developments if the project is within the boundaries of the ward they represent.
Bus Rapid Transit (BRT) systems have become increasingly common in US cities. BRT stations provide a local amenity by improving transportation options for local residents, but may also represent a local nuisance due to noise or displacement of other road users. We estimate whether BRT is priced into local real estate by studying a recently opened BRT project in Vancouver, Washington. We use a difference-in-difference method with both hedonic and repeat sales estimators to test for a price effect. We estimate a 5-6% price premium for homes located within a 20 minute walk of a BRT station. Effects were heterogeneous according to neighborhood racial composition. We find larger effects in neighborhoods with low white population shares and marginally negative effects in neighborhoods with high white population shares. Overall, BRT generated new real estate value that exceeded the project's construction costs by a factor of six. We discuss how government could leverage future residential appreciation to fund construction of BRT projects.
Over 100,000 pedestrians have been struck and killed by vehicles on US roadways in the first two decades of the 21st century, representing an alarming public health issue. We examine the US Interstate Highway System's legacy in contributing to local pedestrian deaths using historical Interstate Highway plans as an instrument for local Interstate construction. Operating an Interstate through a census tract increased pedestrian deaths significantly. Among 17,000 tracts bisected by Interstates, we estimate the average tract experienced 2.5 additional pedestrian deaths between 2001-2020 due to the presence of the Interstate. We find these deaths occur disproportionately in Black communities.
The provision of public transportation can improve the accessibility of work opportunities, particularly for low-income residents. However, predicting the labor market effects of new transit infrastructure is difficult because workers may endogenously adjust location, commute mode, and work decisions based on the existence of the infrastructure. I examine a large public transit rail project on the island of Oʻahu, Hawaiʻi. Using a matrix of census block level travel times, I propose and estimate a structural model of location and mode choice for workers on Oʻahu. I use estimated parameters to predict the effects of the rail project. I find the new rail system substantially increases the use of public transit and increases the employment rate, particularly among low-income workers. Accounting for endogenous household decisions through structural modeling is key to the findings. High-income workers have a strong preference for driving and a low preference for the neighborhoods in which rail was constructed, this allows low-income workers to capture a high share of transit's direct benefits.