Category Archives: healthy communities

Health benefits of switching to transport and bikes

Some of the most robust research, internationally, of the health benefits derived from switching car use to other modes is coming out of the Centre for Research in Environmental Epidemiology (CREAL) in Barcelona. They have looked at the impacts of Barcelona’s bike-sharing system in the past. Their latest work is more generally about the benefits of public transport and bike. Yes, they are working with future scenarios. Yes, there are lots of assumptions embedded. But the framework and the identification of key outcomes and specific measures is good to see.

Cover imageReplacing car trips by increasing bike and public transport in the
greater Barcelona metropolitan area: A health impact assessment study
Environment International
Volume 49, 15 November 2012, Pages 100–109
Rojas et al.


Estimate the health risks and benefits of mode shifts from car to cycling and public transport in the metropolitan area of Barcelona,Spain.
We conducted a health impact assessment (HIA), creating 8 different scenarios on the replacement of short and long car trips, by public transport or/and bike. The primary outcome measure was all-cause
mortality and change in life expectancy related to two different assessments: A) the exposure of travellers to physical activity, air pollution to particulate matter < 2.5 μm (PM2.5), and road traffic fatality; and B) the exposure of general population to PM2.5, modelling by Barcelona Air-Dispersion Model. The secondary outcome was a change in emissions of carbon dioxide.
The annual health impact of a shift of 40% of the car trips, starting and ending in Barcelona City, to cycling (n = 141,690) would be for the travellers who shift modes 1.15 additional deaths from air pollution, 0.17 additional deaths from road traffic fatality and 67.46 deaths avoided from physical activity resulting in a total of 66.12 deaths avoided. Fewer deaths would be avoided annually if half of the replaced trips were shifted to public transport (43.76 deaths). The annual health impact in the Barcelona City general population (n = 1,630,494) of the 40% reduction in car trips would be 10.03 deaths avoided due to the reduction of 0.64% in exposure to PM2.5. The deaths (including travellers and general population) avoided in Barcelona City therefore would be 76.15 annually. Further health benefits would
be obtained with a shift of 40% of the car trips from the Greater Barcelona Metropolitan which either start or end in Barcelona City to public transport (40.15 deaths avoided) or public transport and
cycling (98.50 deaths avoided).The carbon dioxide reduction for shifting from car to other modes of transport (bike and public transport) in Barcelona metropolitan area was estimated to be 203,251
t/CO2 emissions per year.

Interventions to reduce car use and increase cycling and the use of public transport in metropolitan areas, like Barcelona, can produce health benefits for travellers and for the general population of the
city. Also these interventions help to reduce green house gas emissions.

  • We assess the health impacts of replacing car trips by bicycle or public transport.
  • Replacement of the car trips reduces mortality in travellers who shift the mode.
  • Replacement of the car trips also reduces mortality in residents of urban areas.
  • Replacement of car trips can reduce the emissions of CO2.

Cycling on busy roads and concentrated auto exhaust

I received the following email inquiry this morning:


Mr Krizek,

Some have questioned the wisdom of promoting bike use on roadways especially very busy ones or at busiest times because of the health hazards of heavy breathing in concentrated auto exhaust.
What can you say about that?

Here is a response, fresh off the press from the book recently edited by John Parkin of the UK:

Kevin J. Krizek (2012). Cycling, Urban Form and Cities: What Do We Know and How Should We Respond? Cycling and Sustainability; Transport and Sustainability, Volume 1. John Parkin, editor. Chapter 5; 111-130. Emerald Group Publishing, UK.

…from page 121

“Some recent research on cycling aims to better understand unintended consequences linked with increased exposure to air pollution (Panis, 2011; Zuurbier et al., 2010). Despite the many virtues of cities for cycling, including relatively high land use densities, a drawback to cycle use is related to air quality and this becomes more important when the activity in question requires significant amounts of oxygen intake. Air pollution can affect the respiratory system because of the deep draw down of air into the lungs and may even lead to heart rate variability (Weichenthal et al., 2011). Of particular concern are ultrafine particulates. Hazards from air pollution are extremely localized and require close proximity (a very few metres), which is just the position of cycle traffic in relation to localized air pollution problems caused by motor traffic. Various treatments have been proposed such as separating cycle traffic from motor traffic by more than the requisite distance, allowing and encouraging bicycles to wait for a traffic signal green light in front of the queue of motor traffic (in so-called bicycle boxes or behind so-called advanced stop lines, which also then have the advantage that they allow cycle traffic a head start before motor traffic accelerates from a stop), or, through appropriate area wide traffic management to create a tiered system of routes with cycle traffic and motor traffic encouraged to use adjacent parallel routes. Overall, however, the evidence suggests that there are potential consequences to cycling in urban areas dominated by motor traffic that need to be addressed in order to avert the potential for cycling in cities being increasingly associated with health risks (Zuurbier et al., 2010).”

Results from Active Transportation Workshop

I participated in (and helped organize) the Kaiser Permanente Active Transportation Indicators Workshop on March 15. The purpose of the workshop was to help establish a set of consensus indicators for measuring various aspects of Active Transportation (AT) in Colorado that meet the needs identified by the attendees’ organizations and other organizations with which they work. It was one data collection process, which is part of a larger project sponsored by Kaiser Permanente (KP) to: identify model examples of how to measure active transport; a particular focus is on those currently being used in Colorado; convene experts and stakeholders to advise the best data collection methods to use at a larger scale in Colorado; and recommend a menu of instruments or tools for gathering data for those indicators.

The Workshop was held at the Kaiser Permanente Educational Theater Program Facility in Englewood. There were 30 participants and 7 Project Team members.

After considerable discussion and vetting of different ideas, the following question was posed for voting after the morning session: what are the needs for which AT indicators should be developed. The top three responses are:

  1. For AT data to be better standardized (like we do for cars that would enable comparison and scaling), 18 votes
  2. To better assess the impacts of various AT projects (before and after evaluation), 14 votes
  3. To understand the needs of disadvantaged groups or other small areas, possibly focusing on key demographic populations, 13 votes
A full report and webinar of the project will be held April 19 at 8 am. Details to come.

Coming soon to a TV near you: a PBS special on healthy communities with academics from Boulder prattling about bike paths

Coming soon to a TV near you: a PBS special on healthy communities with academics from Boulder prattling about bike paths
Popular press pieces that promote a certain ideology or urban planning mission often come across as “duh.” Kool-aid consumers are already aware of the central arguments. Most academics get queasy with the oversimplifications. Opponents of the arguments find it to too easy to roll their eyes.
But, most of these popular press things still play a role. They at least get people talking.
A high-quality, high-gloss, and high-content PBS special is being rolled in most TV markets this month on Designing Healthy Communities. In the Denver area, it is airing this Sunday, February 12, on KDVR Channel 12 at 8:00pm. Check your station here.
I appear in Episode 1 times a few times prattling about bike paths and Boulder’s situation. Is there anything new here? It is fun to see Dr. Richard Jackson speaking so authoritatively, confidently, and conclusively about so many diverse matters. It is fun to see how the producers wove so many different threads together. And, it is fun to see my sun tea brewing in my own backyard.