More Lanes are (Still) a Bad Thing
Not Just Bikes・2 minutes read
Road widening projects do not solve traffic congestion as expanding roads leads to increased traffic due to behavior changes. Transportation decisions are influenced by ease of access, impacting where people live, work, and travel, with induced demand and latent demand contributing to congestion and suburban sprawl.
Insights
- Planners have long understood that road widening projects do not alleviate traffic congestion due to induced demand, where expanding roads leads to increased traffic as behaviors change.
- Successful strategies to reduce traffic congestion involve prioritizing mixed-use zoning, public transit, and pedestrian/cycling infrastructure improvements, as seen in cities like Arlington and Oslo.
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Recent questions
Why do road widening projects fail to reduce traffic congestion?
Road widening projects have historically failed to alleviate traffic congestion because of the concept of induced demand. When roads are expanded, more drivers are attracted to use them, leading to increased traffic as people adjust their behaviors. This phenomenon results in new trips and travel patterns that negate the benefits of expanded road capacity. Additionally, wider highways can contribute to suburban sprawl and changes in land use, further exacerbating congestion.
How do transportation decisions impact where people live and work?
Transportation decisions heavily influence where people choose to live, work, and travel. The ease of access to different areas, such as through road networks or public transit options, plays a significant role in shaping urban development patterns. Cities that prioritize mixed-use zoning, public transit, and pedestrian/cycling infrastructure improvements can successfully reduce traffic congestion by providing alternative transportation options and encouraging more sustainable travel behaviors.
What is the key concept behind the failure of road widening projects?
The key concept behind the failure of road widening projects is induced demand. This phenomenon occurs when expanding roads leads to an increase in traffic due to changed behaviors, such as more people choosing to drive or taking longer trips. As a result, the additional road capacity created by widening projects is quickly filled up by new drivers, ultimately resulting in continued congestion and the need for further infrastructure expansion.
Why do traffic engineers often prioritize building highways despite congestion issues?
Traffic engineers often prioritize building highways due to financial incentives and the perceived short-term benefits of increased road capacity. However, this approach can perpetuate the cycle of congestion by attracting more drivers to use the expanded roads, leading to induced demand and continued traffic issues. Additionally, the focus on highway construction can neglect alternative transportation solutions that may be more effective in reducing congestion in the long run.
How do wider roads contribute to increased traffic congestion?
Wider roads contribute to increased traffic congestion by attracting more drivers to use them, leading to higher levels of traffic as people adjust their lifestyles. The concept of induced demand plays a significant role in this process, as expanded road capacity can result in new trips and travel patterns that negate the benefits of the wider roads. Additionally, wider highways can lead to traffic backups at intersections and merging points, worsening congestion despite the initial intention of alleviating traffic flow.
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Summary
00:00
Road Widening Fails to Ease Traffic Congestion
- Road widening projects have historically failed to alleviate traffic congestion, despite continued investment.
- Planners have long understood that adding more lanes does not solve traffic issues, dating back to the 1930s.
- Induced demand is a key concept where expanding roads leads to more traffic due to changed behaviors.
- Transportation decisions are heavily influenced by ease of access, impacting where people live, work, and travel.
- Road widening projects are complex and time-consuming, requiring years to complete while traffic remains a challenge.
- Wider highways attract more drivers, leading to increased congestion as people adjust their lifestyles.
- Induced demand results in new trips and travel patterns that negate the benefits of expanded road capacity.
- Latent demand, immediate upon road expansion, includes those who refrained from traveling due to congestion.
- Land use changes accompanying road expansions contribute to induced demand and suburban sprawl.
- Traffic engineers often prioritize building highways due to financial incentives, perpetuating the cycle of congestion.
16:33
Efficient Urban Design Reduces Traffic Congestion
- Drivers merging in and out cause traffic backups, worsened by wider roads.
- Intersections require multiple lanes for turning cars to not impede through traffic.
- A chart by the National Association of City Transportation Officials in the US estimates single travel lane capacities for various transportation types.
- Dutch road design prioritizes moving people efficiently over cars, utilizing lanes for public transit and cycling.
- Cities like Arlington and Oslo successfully reduce traffic by focusing on mixed-use zoning, public transit, and pedestrian/cycling infrastructure improvements.
