Lewis–Mogridge Position

Published Mar 22, 2024

Definition of the Lewis–Mogridge Position

The Lewis–Mogridge Position, also known as the theory of induced demand, states that increasing the capacity of roadways or other forms of transportation infrastructure does not ease congestion but instead generates more traffic. This concept suggests that as a city expands its road network to accommodate more traffic, the number of vehicles using these roads also increases, effectively negating any initial reductions in congestion.

Example

To illustrate the Lewis–Mogridge Position, consider the scenario of a city that decides to build a new freeway to reduce traffic congestion. Initially, after the freeway opens, traffic flow improves, and congestion decreases. However, over time, more people choose to use personal vehicles due to the availability of better road infrastructure, leading to an increase in traffic volume. Additionally, new commercial and residential developments might spring up along the freeway, further increasing traffic. As a result, the freeway soon becomes just as congested as the roads it was meant to relieve if not more so. This phenomenon showcases the core assertion of the Lewis–Mogridge Position: expanding road infrastructure can induce more traffic, ultimately leading back to the original levels of congestion.

Why the Lewis–Mogridge Position Matters

Understanding the Lewis–Mogridge Position is critical for urban planners, policymakers, and transportation engineers as it challenges traditional approaches to solving urban congestion. It suggests that merely increasing the supply of road space is not a sustainable solution for traffic congestion. Instead, this perspective encourages the exploration of alternative strategies such as improving public transportation, encouraging carpooling, implementing congestion pricing, or promoting non-motorized modes of transport like cycling and walking. Recognizing the limitations of expanding road capacity can lead to more innovative and effective urban development policies that focus on sustainability and effective traffic management.

Frequently Asked Questions (FAQ)

Does the Lewis–Mogridge Position suggest that all road expansions are futile?

Not necessarily. While the Lewis–Mogridge Position highlights the phenomenon of induced demand, it does not argue that all road expansions are ineffective. In certain contexts, expanding roadways may be necessary and beneficial. However, this theory emphasises that road expansions alone cannot solve congestion issues in the long term and should be part of a broader, more integrated approach to transportation planning that includes demand management strategies.

How can cities address congestion without inducing more traffic?

Cities can address congestion through various methods that do not induce additional traffic. These include improving public transportation infrastructure to provide efficient and attractive alternatives to driving, implementing congestion pricing to discourage peak-time travel, promoting bicycle and pedestrian infrastructure to reduce reliance on cars, and developing land use policies that encourage mixed-use developments and reduce the need for long commutes.

Are there any real-world examples where increasing road capacity did not lead to increased traffic?

Real-world examples where increasing road capacity did not significantly increase traffic are rare, as the phenomenon of induced demand is widely documented. However, there have been cases where interventions have been carefully paired with measures to manage demand, such as improved public transit or congestion pricing, where the negative impacts of induced demand have been mitigated. These examples reinforce the idea that tackling congestion effectively requires a multifaceted approach rather than relying solely on expanding road infrastructure.

By understanding the dynamics of the Lewis–Mogridge Position, stakeholders can better navigate the complexities of urban transport planning, moving towards solutions that consider long-term sustainability and efficiency over temporary congestion relief.