Congestion Externalities Research Articles

Dependency Model with Congestion and Tourism

This paper presents results regarding the impact of regional and international tourism on the welfare of the domestic economy in the presence of congestion. The model used for this purpose is the dependency model of trade. Three main results are obtained from our investigation. First, it is established that an increase in regional tourism is welfare enhancing in the absence of congestion externalities due to an improvement in the tertiary terms of trade. Second, it is shown that in the presence of congestion, the welfare effect of an increase in tourism is ambiguous as there are three effects: 1) an improvement in the tertiary terms of trade, 2) a congestion effect and 3) a favorable effect on congestion via a decline in it due to the price effect. To correct the distortions policy intervention is required. This takes the form of two simultaneous policies: a tax on the goods consumed by the tourists and a tax on congestion by creating property rights. The results are of great significance for policy making.

The Lockdown Impact on Unemployment for Heterogeneous Workers

We develop a multi-sectoral matching model to predict the impact of the lockdown on the US unemployment, considering the heterogeneity of workers to account for the contrasted impacts across various types of jobs. We show that separations and business closures that hit the workers with the first level of education explains the abruptness of the unemployment rise. The existence of significant congestion externalities in the hiring process suggests that a comeback to the pre-crisis unemployment level could be reached in 2024 in a scenario with a double wave. In the same scenario, a calibration on French data leads to more pessimistic forecasts with a comeback to the pre-crisis unemployment level expected until 2027.

Congestion and Incentives in the Age of Driverless Cars

Following the development of autonomous vehicles (AVs) and GPS systems, fleets will gain prominence over private vehicles. We analyze the welfare effects of the transition from a fully decentralized regime, in which all travelers are atomistic and do not internalize the congestion externality, to a centralized regime, where all travelers are supplied by a fleet of AVs controlled by a monopolist. In our model, heterogeneous individuals differing in the disutility from congestion may travel on one of two lanes, which may endogenously differ in the level of congestion, or they may not travel. We show that the monopolist sorts travelers across the two lanes differently than the decentralized regime. Moreover, depending on the severity of congestion costs, it may also exclude some travelers. We find that centralization is always welfare detrimental when the monopolist does not ration travel. If instead rationing occurs, centralization may be welfare beneficial, provided that congestion costs are sufficiently high. We then analyze how to restore first best with road taxes. While congestion charges are optimal under decentralization, taxes differ markedly in a centralized regime, where restoring first best may require subsidizing the monopolist.

Costly Commuting and the Job Ladder

Even though workers in the UK spent just 1,000 pounds on commuting in 2017, the economic loss may be far higher because of the congestion externality arising from the way in which one worker's commute affects the commuting time of others. I provide empirical evidence that commuting time affects job acceptance, pointing to large indirect costs of congestion. To interpret the empirical facts and quantify the costs of congestion, I build a model featuring a frictional labor market within a metropolitan area. By endogenizing commuting congestion in a labor search model, the model connects labor market responses to urban policies. Workers evaluate job offers based on their productivity and commuting costs, taking congestion as given, but by accepting and commuting to distant jobs, affect other workers' labor market outcomes. Through this mechanism, equilibrium moving decisions, housing rent, and wages are tightly linked to congestion. Calibrating the model to the local labor market around London, I show that the effect of the congestion externality is to significantly decrease welfare and increase wage inequality. I quantify the effects of a congestion tax on labor market outcomes, and show that the welfare-maximizing tax has substantial negative effects on inequality, but comes at a cost of higher unemployment.

Private and public liquidity provision in over‐the‐counter markets

We show that trade frictions in over‐the‐counter (OTC) markets result in inefficient private liquidity provision. We develop a dynamic model of market‐based financial intermediation with a two‐way interaction between primary credit markets and secondary OTC markets. Private allocations are generically inefficient due to a congestion externality operating through market liquidity in the OTC market. This inefficiency can lead to liquidity that is suboptimally low or high compared to the second best, providing a rationale for the regulation and public provision of liquidity. Moreover, our model characterizes a transmission channel of quantitative easing or tightening that operates through liquidity premia.

Airport Pricing and Capacity: Schedule versus Congestion Delays

This study investigates airport pricing and capacity investment when passengers face schedule and congestion delays. Two countries’ airports are served by each country’s home carrier. Airports choose their charges on a per-flight and/or per-passenger basis. Carriers choose both quantities and frequencies. Given the general observation that carriers that compete on parallel international routes often form codeshare alliances to increase the schedule they are able to provide, we find the following. First, the first-best per-flight charges (rules) do not necessarily need to charge congestion delay costs if there is a positive externality (an increase in one carrier’s flights can reduce the schedule delay costs for its allied carriers’ passengers) that can compensate for the negative congestion externality. Second, when positive and negative externalities cancel out, choosing per-passenger charges alone and fixing the per-flight charges (known as the second-best approach) can also lead to the first-best outcome. However, choosing per-flight charges alone and fixing the per-passenger charges (another second-best approach) cannot do so. Third, under the former second-best pricing approach, each airport underinvests (overinvests) when the congestion delay effect dominates (is dominated by) the schedule delay effect. Interestingly, when the positive and negative externalities cancel out, capacity investment is globally efficient. However, under the latter second-best pricing approach, each airport overinvests.

Bringing the efficiency of electricity market mechanisms to multimodal mobility across congested transportation systems

Abstract A central challenge facing Mobility as a Service (MaaS) is mispricing of its a core input: the use of scarce road space. A transparent real-time market for road use is essential for MaaS to reach its full potential. We focus on how network-wide, real-time markets for road use support MaaS, and how such markets can be developed. In our proposed network-management scheme, roadway tolls (for entire trips – from origin to destination) are determined in a two-stage market hosted by an independent system operator or “ISO”. Service providers purchase the product (the right to use a series of road segments at a reasonably specific time of day) in the day-ahead market. In real-time, the market becomes physical and operates under the principle of open access: road capacity cannot be withheld in real time and its use is determined by users’ decisions, guided by prices and suggested routings. Real-time road-use prices are computed using clearing prices that balance real-time supply and demand. Those with pre-paid slots can be paid to delay their travel, to create space for high bidders during periods of suddenly low capacity or unexpectedly high demand. Such policies and programs can avoid excessive congestion, provide reliable travel times, and keep traffic moving, especially as automation makes car and truck travel easier. Such policies are critical in helping cities and regions avoid gridlock. They ensure that travelers internalize congestion externalities, while enabling MaaS and other transport providers to deliver higher-quality mobility service for all travelers. Thoughtful marriage of week-ahead, day-ahead and real-time road pricing for travelers on congested networks can deliver efficient transportation systems that save time and energy, while providing signals for optimal infrastructure investment.

The Economics of Line-Sitting

This paper studies an emerging business model of line-sitting in which customers seeking service can hire others (line-sitters) to wait in line on behalf of them. We develop a queueing-game-theoretic model that captures the interaction among customers, the line-sitting firm, and the service provider to examine the impact of line-sitting on the service provider’s revenue and customer welfare. We also contrast line-sitting with the well-known priority purchasing scheme, as both allow customers to pay extra to skip the wait. Our main results are as follows. First, we find that both accommodating line-sitting and selling priority can bring in extra revenue for the service provider, although by different means—selling priority increases revenue mainly by allowing the service provider to practice price discrimination that extracts more customer surplus, whereas line-sitting does so through demand expansion, attracting customers who would not otherwise join. Second, the priority purchasing scheme tends to make the customer population worse off, whereas line-sitting can be a win–win proposition for both the service provider and the customers. Nevertheless, having the additional option of hiring line-sitters does not always benefit customers as a whole because the demand expansion effect also induces negative congestion externalities. Finally, despite the fact that the service provider collects the priority payment as revenue but not the line-sitting payment, which accrues to the third-party line-sitting firm, we demonstrate that, somewhat surprisingly, accommodating line-sitting can raise more revenue for the service provider than directly selling priority. This paper was accepted by Charles Corbett, operations management.

Regulating dynamic congestion externalities with tradable credit schemes: Does a unique equilibrium exist?

Tradable credit schemes offer a potentially efficient, revenue-neutral policy alternative to classical dynamic pricing of congestion externalities. We show in this paper that the resulting equilibrium may not be unique for particular models of congestion, including the first-best solution for the conventional Vickrey's bottleneck model. This can have substantial detrimental impacts on social welfare and social acceptance of tradable credit schemes. The reason underlying this result is that the credit supply-demand condition can be satisfied for a continuum of credit prices. This is because any marginal change in the credit price will be matched by a compensating change in queuing times, keeping user price fixed but deviating from the first-best optimum in which no queueing should occur. We find that the problem of non-uniqueness does not occur for the dynamic flow congestion model proposed by Chu. A unique equilibrium can be obtained in the bottleneck model if the buying and selling of credits with a bank is allowed, against a pre-determined price. Credits are then still tradable so that the use can deviate from the initial distribution, but the credit price is determined by the perfectly elastic demand and supply from the bank.

Procuring Spontaneous Session-Level Resource Guarantees for Real-Time Applications: An Auction Approach

Real-time multimedia applications, such as interactive gaming, live video streaming, and augmented reality, have strict latency and bitrate requirements. However, unpredictable network conditions, such as congestion and link quality, can severely degrade the quality of experience (QoE). While buffer-based mitigations cannot be applied to real-time applications due to their immediate resource needs, recent innovations in network slicing have demonstrated the feasibility of dedicating specified amounts of network resources to individual sessions in the radio access network. Encouraged by this, we propose to reserve network resources for multimedia sessions in real time according to their declared needs, thereby providing ad hoc session-level performance guarantees . Through Wi-Fi experiments and trace-driven LTE simulations, we show that such session-level resource provisioning is robust to real-time channel fluctuations and congestion externalities over the lifetime of a session. This approach, however, raises challenges: how can the network ensure that users are honest about their resource needs and optimally allocate its limited resources to users under uncertainty in future sessions’ resource needs ? We derive a novel multi-unit combinatorial auction (MUCA) model with a unique structure that can be exploited for fast winner determination, and yet incentivize truthful bidding, properties not simultaneously achieved in a generic MUCA but essential to making real-time session guarantees. Furthermore, since dynamic bidding in real time is challenging for end-users who are budget-constrained, we develop a reinforcement learning-based utility-maximizing strategy to distribute their budget across sessions and show that it yields high user utility.

Stuck in Traffic: Measuring Congestion Externalities with Negative Supply Shocks

Traffic congestion is one of the most challenging issues of urban agglomeration. Congestion costs are often higher than their socially optimal levels, and little is known about the key parameters needed to design optimal congestion policies. This paper addresses this issue by exploiting an exogenous reduction in for-hire vehicle supply in New York City. I estimate the effect of a vehicle on congestion and document substitution patterns to other transportation modes. A 9.1 percent reduction in the number of active vehicles decreases congestion by 0.46 minutes per mile. As vehicles leave the streets, for-hire trips decrease, resulting in increased waiting times and people switching to other transportation modes. Welfare increases for those who travel by vehicle because travel time is reduced. However, welfare decreases for those who face increased wait times or switch to a less-preferred transportation mode. A calibration exercise suggests daily net welfare gains between $0.5 and $1.0 million.

The Welfare Effects of Greenbelt Policy: Evidence from England

I measure the economic effects of greenbelts that prohibit new construction beyond a predefined urban fringe and therefore act as urban growth boundaries. I focus on England, where 13% of the land is designated as greenbelt land. I estimate a quantitative general equilibrium model that includes amenities, housing construction, a traffic congestion externality, agglomeration forces, productivity and household location choices. To identify causal effects of greenbelt land, I construct counterfactual greenbelts, use greenbelt land in 1973, or focus on areas within a km of greenbelt boundaries. Greenbelt policy appears to generate positive amenity effects, but also strongly reduces housing supply. I find the greenbelts seem to increase welfare, as the equivalent income increase of workers is 0.3% and land rents increase by about 6.5%. Whether greenbelts benefit workers critically depends on the presence of spillovers and greenbelt amenities.

Henry George and Mohring–Harwitz Theorems: Lessons for Financing Smart Cities in Developing Countries*

Developing countries are embarking on ‘smart city’ programmes to rejuvenate their cities as engines of economic growth, applying smart solutions and managerial innovations. However, they ignore the powerful externalities of cities and are far from adopting ‘smart’ ways of financing urban infrastructure and services based on known theories and international practices. This article combines the Henry George Theorem (HGT) from Urban Economics and Mohring–Harwitz Theorem (MHT) from Transport Economics to suggest a robust strategy of financing infrastructure in cities. While the HGT emphasizes the taxation of urban land value, the MHT advocates the pricing of congestion externalities. The article suggests that if ‘beneficiaries pay’ and ‘congesters pay’ principles are combined, cities in developing countries like India can generate adequate revenues to service long-tenor debt incurred for core infrastructure facilities. It presents a toolbox of instruments to finance urban infrastructure.

An endogenous equilibrium game on traffic congestion externalities

Traffic congestion and road tolls are familiar economic concepts for most undergraduates; however, students often have difficulty explaining exactly how theoretical principles like externalities and social welfare are related to their real-world experiences, such as driving. The authors present a classroom exercise to demonstrate how congestion externalities are generated, the effects on private and social welfare, and how appropriately priced tolls can address congestion externalities. Students are asked to evaluate outcomes in five different driving scenarios, with and without congestion or tolls. The authors offer discussion questions to make the activity engaging and informative. They report the results of their efforts to administer the exercise. This 75-minute exercise is appropriate for introductory or intermediate microeconomics, political economy, or environmental economics classes of various sizes.

Regulating Dynamic Congestion Externalities With Tradable Credit Schemes: Does a Unique Equilibrium Exist?

Tradeable credit schemes offer a potentially efficient, revenue-neutral policy alternative to classical dynamic pricing of congestion externalities. We show in this paper that the resulting equilibrium may not be unique for particular models of congestion, including the first-best solution for the conventional Vickrey’s bottleneck model. This can have substantial detrimental impacts on social welfare and social acceptance of tradable credit schemes. The reason underlying this result is that the credit supply-demand condition can be satisfied for a continuum of credit prices. This is because any marginal change in the credit price will be matched by a compensating change in queuing times, keeping user price fixed but deviating from the first-best optimum in which no queueing should occur. We find that the problem of non-uniqueness does not occur for the well-known dynamic flow congestion model proposed by Chu. A unique equilibrium can be obtained in the bottleneck model if the buying and selling of credits with a bank is allowed, against a pre-determined price. Credits are then still tradeable so that the use can deviate from the initial distribution, but the credit price is determined by the perfectly elastic demand and supply from the bank.

Airport slots and the internalization of congestion by airlines: An empirical model of integrated flight disruption management in Brazil

This paper examines the relationship between the control of airport slots by major airlines and their incentives to engage in service quality. We investigate a set of airline strategies regarding possible practices of slot hoarding and slot concentration through mergers aiming at erecting airport barriers to entry. We develop an econometric model of flight disruptions by allowing an integrated management of flight delays, cancellations, aircraft size, price and passengers per flight. We consider the case of the domestic airline industry in Brazil. We find evidence of the internalization of congestion externalities by dominant carriers. We also have some evidence of schedule padding, a strategic trade-off between delays and cancelations, and slot hoarding following a merger. Our results suggest that carriers intensify the internalization of congestion externalities when slot flight concentration increases.

Efficient Mismatch

This paper presents a model in which mismatch employment arises in a constrained efficient equilibrium. In the decentralized economy, however, mismatch gives rise to a congestion externality whereby heterogeneous job seekers fail to internalize how their individual actions affect the labor market outcomes of competitors in a common unemployment pool. We provide an analytic characterization of this distortion, assess the distributional nature of the associated welfare effects, and relate it to the relative productivity of low- and high-skilled workers competing for similar jobs.

Professional sporting events and traffic: Evidence from U.S. cities

AbstractSporting events concentrate people in facilities on game day. No evidence currently exists linking sporting events to traffic conditions. We analyze urban mobility data from 25 metropolitan areas with Major League Baseball (MLB) teams over the period 1990–2014. MLB‐related travel accounts for at most 0.5 percent of annual metropolitan area vehicle‐miles traveled (VMT). Instrumental variable regression results indicate MLB attendance causes an increase of about 5 million VMT, about 28,000 additional annual hours of traffic delay, and over $7 million annually in social costs from CO2 emissions in host cities. MLB games generate congestion externalities.

Traffic density, congestion externalities, and urbanization in China

ABSTRACTAlthough there is an abundant regional literature analyzing traffic congestion, only a few studies have explored extending such analysis with spatial effects. This study uses a dynamic spatial Durbin model and city-level panel data for the period 2003–14 to investigate the spatial spillover effects of traffic congestion on urbanization in China. The results show that there is an inverted ‘U’-shaped relationship between urbanization and traffic density in local and neighbouring cities, and congestion effects have appeared. In the short and long run, the spatial effects of traffic congestion have become an important force restricting the effective promotion of urbanization in China.

Airport Slots and the Internalization of Congestion by Airlines

This paper examines the relationship between the control of airport slots by major airlines and their incentives to engage in service quality. We investigate a set of airline strategies regarding possible practices of slot hoarding and slot concentration through mergers aiming at erecting airport barriers to entry. We develop an econometric model of flight disruptions by allowing an integrated management of flight delays, cancellations, aircraft size, price and passengers per flight. We consider the case of the domestic airline industry in Brazil. We find evidence of the internalization of congestion externalities by dominant carriers. We also have some evidence of schedule padding, a strategic trade-off between delays and cancelations, and slot hoarding following a merger. Our results suggest that carriers intensify the internalization of congestion externalities when slot flight concentration increases.