Yousaf Shah, Urban Planning Consultant, recently answered the following question on Quora:
“What’s the quickest way to solve a city’s traffic congestion?”
Read Yousaf’s response and others’ below:
Traffic congestion is partly a result of infrastructure planning and development, but mostly it is a symptom of economic growth.
Infrastructure development is not dynamic - capacity is built to accommodate a certain threshold at one time; once that threshold is reached, congestion occurs. Demand, however, increases according to a variety of factors beyond just the road capacity and the economy is a major driver. As the economy grows and more people can afford to buy cars, the roads slowly fill up. Increasing road capacity is, on its own, an ineffective way to combat congestion because you are not really addressing the root cause of the congestion, just a symptom. Therefore, the quickest way to solve a city’s traffic congestion is, in fact, to kill the economy so fewer people can afford to drive (that’s a bit extreme I guess, you could just make it more expensive to drive through taxation).
For less quick, more sustainable solutions, one needs to consider the principle of the triple convergence (increasing road capacity = more cars due to economic growth + more people now taking the improved road during peak hours who had previously shifted to off peak hours to avoid congestion + more people now taking the improved road who used to take other forms of transportation to avoid congestion = more congestion). Congestion needs to be addressed as part of a systemic upgrade of the entire transportation network, not just a single component of it.
However, as I mentioned above, demand is continuous and dynamic and infrastructure development is not. Congestion is, therefore, the point of equilibrium on the demand/supply graph, and no matter what a city does, economic theory says that equilibrium will always occur. As a result, congestion is inevitable. It is better to manage congestion than to try to “solve” it.
Other perspectives:
Don’t. Traffic congestion is the most efficient way to use a road. It is also safer (less accidents and fatalities per capita). And it is the best incentive for individual drivers to find alternative methods for getting around in the city.
A far better solution is to fund infrastructure that supports alternatives to driving a car:
- Develop complete neighbourhoods, that allow most residents to walk to most of the services and amenities they need.
- Develop high density urban centres, and stop or discourage the development of suburbs.
- Design streets that are safe and attractive for all users according to a set of priorities that places pedestrians, cyclists, bus riders first and drivers last.
- Build an extensive network of bike trails and cycling infrastructure (bike lockers, bike rental stations, bike stands, etc.).
- Create a reliable and extensive bus system which may include, as needed, “Rapid Bus” service.
- Develop a tram, trolley, moving sidewalk, and subway system as needed in areas of highest density to link remote areas to a core urban area.
- Discourage the development of parking lots, encourage a policy that reducing parking requirements throughout the city.
The best way (but, maybe not the quickest way) to deal with traffic congestion is to make alternatives to driving easier, safer and more attractive. The sooner this is done the sooner the city can reap the economic, social, public health and public safety benefits that result from having a more efficient transportation system.
Congestion pricing.
Numerous highways and downtown’s globally place a toll on usage of the road that varies with the time of day, with the highest rates being during the heart of rush hour. By raising the cost to the driver of using a road, usage can be deterred to the point where congestion is eliminated. The lost trips get made at a different time of day (when the toll is lower), are shifted to carpooling or public transit, are made locally, or are simply deemed not worth it. This is considered economically efficient because drivers on a congested road cause negative externalities on the other drivers (by slowing them down) that are not factored into their decision making. This is especially true given that congestion often reduces the throughput of the road and not just speed, making it particularly inefficient.
Congestion pricing has yet to be implemented on a citywide scale and it would require substantial (and that’s an understatement) political will to implement such a system on that scale. However, given GPS technology, in theory it is possible to monitor where and when people drive in a city and price their driving accordingly. There would some be issues with people driving in from out of town, but that could be dealt with as well.