He has been associated with the Cato Institute as an adjunct scholar since 1995 and a senior fellow since 2007. O'Toole was the McCluskey Visiting Fellowship for Conservation at Yale University in 1998, and has served as a visiting scholar at the University of California, Berkeley (1999) and Utah State University (2000). O'Toole studied economics at the University of Oregon, but did not receive a degree in economics. He is the contact listed for the Thoreau Institute.
Early in his career, O'Toole worked with environmental groups to oppose the United States Forest Service's subsidized sales of public forest timber to the timber industry. His book Reforming the Forest Service built on his experience during this effort, and proposed a number of free-market solutions to management of U.S. public land and timber. He has written analyses of the usage and development plans of a number of U.S. national forests, working with state environmental agencies and other groups.
In the 1990s, O'Toole emerged as an outspoken critic of New Urbanist design and smart growth strategies after learning in 1995 of a county plan to rezone his neighborhood to allow higher density and mixed use development. O'Toole contends that these development strategies—in which regulatory measures and tax incentives are employed to encourage denser development, more efficient land use, and greater use of public transportation—ignore the desires and preferences of most housing consumers and ultimately waste public funds. He has campaigned against smart growth policies and light rail systems in several U.S. states as well as in Winnipeg, Manitoba, and Ottawa, Ontario.
His 2001 book, The Vanishing Automobile and Other Urban Myths, was written as a detailed critique of these styles of planning. He continues to advocate for free market solutions to urban planning and design in his writing and teaching.
O'Toole has written three books published by the Cato Institute. The Best-Laid Plans argues that long-range comprehensive government planning necessarily relies on fads and fails to account for current and future public desires and needs. Gridlock looks at the history of transportation in America and argues that the future is in autonomous personal vehicles, not rail transit or high-speed rail. American Nightmare examines the history of housing in America and argues that zoning and, more recently, growth-management planning represents efforts by the middle- and upper-classes to separate themselves from the working class. The Cato Institute has also published more than two dozen other papers written by O'Toole.
While critical of government subsidies to all forms of transportation, O'Toole is a fan of passenger trains and an amateur rail historian. His web site, Streamliner Memories, has more than 15 gigabytes of downloadable historic documents. He has also written about railroad history for Minnesota History magazine.
- Urban planning
- The Vanishing Automobile and Other Urban Myths (Thoreau Institute, 2001) ISBN 0-9706439-0-X
- A Desire Named Streetcar: How Federal Subsidies Encourage Wasteful Local Transit Systems (Cato Institute 2006)
- The Best-Laid Plans (Cato Institute 2007) ISBN 978-1933995076
- Gridlock: Why We're Stuck in Traffic and What to Do About It (Cato Institute 2010) ISBN 978-1935308232
- American Nightmare: How Government Undermines the Dream of Homeownership (Cato Institute 2012) ISBN 978-1937184896.
- Reforming the Forest Service (Island Press, 1988) ISBN 0-933280-49-1
- The Citizens' Guide to the Forest Service Budget (Thoreau Institute) 
- The Citizens' Guide to the Timber Industry (Thoreau Institute)
- Randal O'Toole, The Vanishing Automobile
- Randal O'Toole. The Vanishing Automobile and Other Urban Myths: How Smart Growth Will Harm American Cities. ISBN 978-0970643902.
- Randal O'Toole. The Best-Laid Plans: How Government Planning Harms Your Quality of Life, Your Pocketbook, and Your Future. ISBN 978-1933995076.
- Property Rights Foundation of America, Randal O'Toole biography. Online website: http://prfamerica.org/biography/Biography-OToole-Randal.html
- "Thoreau Institute".
- Congress for the New Urbanism. Debunking Cato: Why Portland Works Better Than the Analysis of Its Chief Neo-Libertarian Critic. Online website: "Archived copy" (PDF). Archived from the original (PDF) on 2014-06-20. Retrieved 2010-07-01.
- Bill Steigerwald (November 5, 2007), "Meet the Anti-Planner". Townhall.com
- Ray Stern, "Anti-Planner" Scholar Randal O'Toole Coming to Phoenix to Talk Up Gridlock Book. Phoenix News Times, Friday, Apr. 30 2010. Online website: http://blogs.phoenixnewtimes.com/valleyfever/2010/04/anti-light-rail_scholar_coming.php
- Randal O'Toole, A Libertarian View of Urban Sprawl and reliance on freeway and highway construction for mobility
- Streets blog NYC,Randal O’Toole: Taking Liberties With the Facts, online:http://www.streetsblog.org/2009/06/02/randal-otoole-taking-liberties-with-the-facts/
- Randal O'Toole, Highway Funding and Urban Form, February 8, 2010. online: http://www.strongtowns.org/journal/2010/2/8/randal-otoole-highway-funding-and-urban-form.html
- Cato Institute, March 18, 2010. Online: http://www.cato-at-liberty.org/2010/03/18/a-libertarian-view-of-urban-sprawl/
- Randal O'Toole, The Best-Laid Plans: How Government Planning Harms Your Quality of Life, Your Pocketbook, and Your Future, https://store.cato.org/book/best-laid-plans-how-government-planning-harms-your-quality-life-your-pocketbook-and-your-future/
- Randal O'Toole, Gridlock: Why We're Stuck in Traffic and What to Do About It, https://store.cato.org/book/gridlock/
- Randal O'Toole, American Nightmare: How Government Undermines the Dream of Homeownership, https://store.cato.org/book/american-nightmare/.
- Cato Studies by Randal O'Toole, https://www.cato.org/people/198/studies/.
- Houston Chronicle. Retrieved from "Archived copy". Archived from the original on 2011-05-22. Retrieved 2007-05-01..
- New York Times, Son of Portland, Oregon tries to puncture myth of 'Smart Growth', https://www.nytimes.com/cwire/2009/07/15/15climatewire-a-son-of-portland-ore-tries-to-puncture-the-52412.html
- Thoreau Institute website; http://www.ti.org/aboutti.shtml
- "Mr. Budd's Historical Expeditions," Minnesota History, Spring, 2016, http://collections.mnhs.org/MNHistoryMagazine/articles/65/v65i01p14-25.pdf.
- "A Desire Named Streetcar: How Federal Subsidies Encourage Wasteful Local Transit Systems".
- "Thoreau Institute Publications Order Form".
- Website including "Antiplanner"
- Streamliner Memories
- Cato Institute profile for O'Toole
- Appearances on C-SPAN
- New York Times: A Son of Portland, Ore., Tries to Puncture the Myth of 'Smart Growth'
- Randal O'Toole at Goodreads