Editing Induced demand (section)

=== Studies ===
[[File:The Vicious Cycle of Predict and Provide (cropped).png|thumb|The [[vicious cycle]] of predict and provide]]
A 1998 meta-analysis by the Surface Transportation Policy Project, which used data from the institute, stated that "Metro areas which invested heavily in road capacity expansion fared no better in easing congestion than metro areas that did not."<ref>{{harvnb|Speck|2012|p=83}}</ref>

On the other hand, a comparison of congestion data from 1982 to 2011 by the Texas A&M Transportation Institute suggested that additional roadways reduced the rate of congestion increase. When increases in road capacity were matched to the increase demand, growth in congestion was found to be lower.<ref>{{cite web |url=http://mobility.tamu.edu/ums/report/ |title=2012 Urban Mobility Report |author=David Schrank |author2=Bill Eisele |author3=Tim Lomax |date=December 2012 |publisher=Texas A&M Transportation Institute |access-date=May 14, 2013 |url-status=deviated |archive-date=2013-04-24 |archive-url=https://web.archive.org/web/20130424103215/http://d2dtl5nnlpfr0r.cloudfront.net/tti.tamu.edu/documents/mobility-report-2012.pdf}}</ref>

A study by [[Robert Cervero]], a professor of City and Regional Planning at the [[University of California, Berkeley]], found that "over a six-to eight-year period following freeway expansion, around twenty percent of added capacity is 'preserved,' and around eighty percent gets absorbed or depleted. Half of this absorption is due to external factors, like growing population and income. The other half is due to induced-demand effects, mostly higher speeds but also increased building activities. These represent California experiences from 1980 to 1994. Whether they hold true elsewhere is of course unknown."<ref>{{Cite web|url=http://americandreamcoalition-org.adcblog.org/highways/induced.pdf |access-date=April 5, 2017 |title=Are Induced-Travel Studies Inducing Bad Investments? |last=Cervero|first=Robert|date=Spring 2003|website=University of California Transportation Center |archive-url=https://web.archive.org/web/20190130110317/http://americandreamcoalition-org.adcblog.org/highways/induced.pdf|archive-date=2019-01-30|url-status=dead}}</ref>

And [[Patricia Mokhtarian|Mokhtarian]] et al. (2002) paired eighteen California state highway segments whose capacities had been improved in the early 1970s with control segments that matched the improved segments with regard to facility type, region, approximate size, and initial volumes & congestion levels. Taking annual data for average daily traffic (ADT) and design-hour-traffic-to-capacity (DTC) ratios during the 21 years 1976–1996, they found the growth rates between the two types of segments to be “statistically and practically indistinguishable, suggesting that the capacity expansions, in and of themselves, had a negligible effect on traffic growth”.<ref>{{Cite journal |vauthors=[[Patricia Mokhtarian|Mokhtarian PL]], Samaniego FJ, Shumway R, Willits NH |year=2002 |title=Revisiting the notion of induced traffic through a matched-pairs study |url=https://www.researchgate.net/publication/263187449|journal=Transportation|volume=29 |issue=2 |pages=193–220|doi=10.1023/A:1014221024304|s2cid=152745459}}</ref>