A group calling themselves A Committee for a Better Sacramento is sponsoring a citizen-initiated ballot measure for the November election, titled “Sacramento County Transportation Maintenance, Safety, and Congestion Relief Act of 2022—Retail Transactions and Use Tax”. (Note: Some people are referring to this as Measure A, but measure letters are assigned by county elections, not by the sponsors. I’ll continue to refer to it as Measure 2022, for now.)
As pointed out in Measure 2022: words have meaning, the word congestion or the term congestion relief is used 24 times in the proposal. It is in fact the major theme of the Transportation Expenditure Plan. 22.4% of the measure is set aside specifically for major congestion relief categories. Since most projects are not individually costed, it can’t be determined how much of the 47.3% for local roads and streets is for congestion relief, but Citrus Heights has two and Elk Grove four called out. The 3.7% for Capital Southeast Connector is also congestion relief.
Not acknowledged, but likely true, is that many of the projects could be considered ‘congestion prevention’, meaning that if roadways and freeways and interchanges are expanded now, future congestion can be prevented.
The committee and supporters seem to have bought into the falsehood that capacity expansion solves congestion. It does not, or rather, solves it for a short period of time, then induced travel returns congestion to previous levels, or higher. It is a never ending cycle. Congestion is not a major contributor to air pollution. It does have an effect, but the effect is very limited in time and space. The big contributor to air pollution, and of course greenhouse gas emissions, is vehicle miles traveled. The measure will increase, not decrease, VMT.
Twenty-eight lanes on the Katy Freeway in Texas have not solved congestion, nor reduced air pollution in Houston. The 405 freeway over the Sepulveda Pass in southern California was widened to the tune of $1 billion dollars in 2011-2012. Traffic is now much worse on the freeway than it was before the widening, and air quality is of course also worse.
Induced travel or induced demand is broadly accepted by researchers in transportation both on a theoretical basis and with many, many case studies, but there is still resistance among some traffic engineers and politicians. The question for me is why those who resist the obvious are writing transportation sales tax measures.
Induced travel says that after spending billions to try to reduce congestion, our roadways will be as congested, or more congested, than they were before.
But over many years of observation and analysis, we have learned that adding supply has a paradoxical outcome. It generates more driving, which is both costly to personal budgets and the environment, and which often re-congests the very roadways we built or expanded.
Caltrans, Rethinking How We Build So Californians Can Drive Less, https://dot.ca.gov/programs/sustainability/sb-743
Empirical research shows that expanded roadway capacity attracts more vehicles. However, environmental impact assesments of roadway expansion projects often ignore, underestimate, or mis-estimate this induced travel effect and overestimate potential congestion relief benefits.
National Center for Sustainable Transportation, https://ncst.ucdavis.edu/tags/induced-travel
Induced demand is “the great intellectual black hole in city planning, the one professional certainty that everyone thoughtful seems to acknowledge, yet almost no one is willing to act upon.”
Speck, Jeff (2012). Walkable City: How Downtown Can Save America, One Step at a Time. New York: North Point Press. ISBN 978-0-86547-772-8.
Induced traffic occurs when new automobile trips are generated. This can occur when people choose to travel by car instead of public transport, or decide to travel when they otherwise would not have.
Wikipedia, https://en.wikipedia.org/wiki/Induced_demand?wprov=sfti1
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