By Todd Litman, Planetizen
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Conventional congestion evaluation tend to be biased in various ways, as summarized in the
following table. For example, conventional evaluation recognizes that wider roads improve
automobile access but ignore their tendency to reduce walking and cycling access (called the
barrier effect), and it favors a hierarchical road system that has higher-speed arterials over a
more connected road system that has lower travel speeds but shorter travel distances. As a
result, mobility-based planning can result in congestion reduction strategies that reduce overall
accessibility by creating sprawled, automobile-dependent communities where activities are
widely dispersed and alternatives to driving are inferior.
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Conventional urban transport planning tends to consider traffic congestion the dominant
planning problem, but more comprehensive and objective analysis indicates that traffic
congestion is actually a moderate cost overall – larger than some but smaller than others – and
roadway expansion is generally less effective and beneficial overall than other congestion
reduction strategies.
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https://www.8-80cities.org/images/res-streets-articles/toward-more-comprehensive-traffic.pdfoldId.20121012140739717