If you are interested in papers currently published, you can look at this source:
http://www.vtpi.org/documents/walking.php
On this page, you will find a link to this paper:
Why Canadians cycle more than Americans: A comparative
analysis of bicycling trends and policies
John Pucher *, Ralph Buehler
Institute of Transport and Logistics Studies, University of Sydney, Newtown NSW 2006, Australia; Bloustein School of Planning and Public Policy,
Rutgers University, 33 Livingston Avenue, Room 363, New Brunswick, NJ 08901, USA
Received 26 May 2005; received in revised form 21 October 2005; accepted 1 November 2005
Abstract
In spite of their colder climate, Canadians cycle about three times more than Americans. The main reasons for this difference are Canada’s higher urban densities and mixed-use development, shorter trip distances, lower incomes, higher costs of owning, driving and parking a car,
safer cycling conditions, and more extensive cycling infrastructure and training programs. Most of these factors result from differences between Canada and the United States in their transport and land-use policies, and not from intrinsic differences in history, culture or resource availability. That is good news, since it suggests the possibility of significantly increasing cycling levels in the United States by adopting some of the Canadian
policies that have so effectively promoted cycling and enhanced its safety. (Emphasis added, jcr)
copyright 2005 Published by Elsevier Ltd.