congestion

As children, we were taught sharing is caring. Turns out it’s also good for business. Opportunities abound to monetize goods and services through joint use: Share your apartment with strangers through room rental services like Airbnb. Turn your car into a taxi service. Wait in line for people who are willing to pay to avoid queueing themselves.

Car emissions account for half of the carbon monoxide pollution in the United States, one third of the nitrogen oxide pollution, and 10% of fine particulate matter emissions. Areas of heavy traffic congestion — which see concentrated emissions levels in the ambient air — are of particular concern, as previous research has linked such pollution with negative effects on fetal health.

Public transportation use varies widely across the United States, from small towns with few transit options to dense metropolitan areas with extensive subway, train and bus systems. Even in cities with similar transit systems, use can vary significantly, and some systems do not efficiently connect where people live to where they work.

There are four primary options for urban transit systems: bus, bus rapid transit, light rail and heavy rail. There has been considerable debate over the systems’ comparative advantages, from lower construction costs to greater carrying capacity.

Train and subway stations play a significant role in both transit networks and the urban environment. While numerous studies have examined stations’ effect on property values, the results have been mixed: Some show a negative impact, others insignificant differences, and some indicate positive effects.

High-occupancy vehicle lanes are intended to both speed traffic and improve air quality. This is done by dedicating a lane to cars with two or more occupants, thus reducing the number of vehicles traveling on the road. This both speeds traffic flows and reduces pollution. Some have argued, however, that if underutilized, such lanes can create congestion.

Automotive transportation, one of the largest sectors of the U.S. economy, has numerous societal benefits but also many downsides — pollution, fatalities, congestion. Getting the price individuals pay for driving to reflect its true cost to society is one of the most significant challenges of public policy.