I test the effect of harsher punishments and sanctions on driving under the influence (DUI). In this setting, punishments are determined by strict rules on blood alcohol content (BAC) and previous offenses. Regression discontinuity derived estimates suggest that having a BAC above the DUI...

This paper derives empirically tractable formulas for the welfare effects of fare adjustments in passenger peak and off-peak rail and bus transit, and for optimal pricing of those services. The formulas account for congestion, pollution, accident externalities, scale economies, and agency...

We study the departure time decisions of commuters traversing a traffic network with the goal of arriving at a common destination at a specified time. There are costs associated with arriving either too early or too late, and with delays experienced at bottlenecks. Our main hypothesis, based on...

We use a simple theory of a system of cities to decompose the determinants of the city size distribution into three main components: efficiency, amenities, and frictions. Higher efficiency and better amenities lead to larger cities but also to greater frictions through congestion and other...

An incentives based theory of policing is developed which can explain the phenomenon of random "crackdowns," i.e., intermittent periods of high interdiction/ surveillance. For a variety of police objective functions, random crackdowns can be part of the optimal monitoring strategy. We...

Speeding tickets are determined not only by the speed of the offender, but also by incentives faced by police officers and their vote-maximizing principals. We hypothesize that police officers issue fines more frequently when drivers have a higher opportunity cost of contesting a ticket, and...