What does it take to convince a whole city to embrace bicycling? Attack the problem in a multifaceted way and put the emphasis on the health benefits of riding, argues transportation researchers John Pucher, Jennifer Dill, and Susan Handy in a review study published this month in Preventive Medicine.
The three planners scoured the scholarly literature for research that looked at what types of interventions–ranging from the installation of bike lanes to raising gas taxes to installing shower facilities in workplaces–were the most effective at increasing cycling levels in a variety of cities.
Their conclusion: The sum of all the parts is far more effective than any individual intervention (though they do grumble quite a bit about the dearth of reliable research in the area, which makes you wonder if they’re hand-waving a bit). Here’s how they put it:
Despite all these caveats and the pressing need for additional research, a clear message emerges from our review: Some individual interventions can increase bicycling to varying degrees, but the increases are not usually large. That does not mean that individual interventions are not important, but they are most effective as a part of a more comprehensive effort. Substantial increases in bicycling require an integrated package of many different, complementary interventions, including infrastructure provision and pro-bicycle programs, as well as supportive land use planning and restrictions on car use.
Since this was a review study it’s brimming with interesting tidbits and statistics. Here are some of the ones that I found most notable:
- A cross-sectional study at the city level of over 40 US cities found that each additional mile of bike lane per square mile was associated with an increase of approximately one percentage point in the share of workers regularly commuting by bicycle (Dill and Carr, 2003)
- A study of Seattle, Washington residents found no relationship between the
presence of a bike lane (objectively measured) and the odds of bicycling, but did ?nd that being near a path mattered. For example, people living within a half-mile of a path were at least 20% more likely to bicycle at least once a week, compared to people living between one-half and one mile away from a path (Vernez-Moudon et al., 2005).
- Using multivariate analysis of the UK’s National Travel Survey—combined with stated preference survey data—Wardman et al. (2007) estimated statistically signi?cant impacts of parking and showers on bicycling levels. Compared to a baseline level of 5.8% of work trips by bicycle, providing outdoor bike parking was estimated to raise the bicycle share to 6.3%. Secure indoor parking raised the bicycle share to 6.6%,and to 7.1% when combined with shower facilities.
- Bicycles on buses and bicycles on rail vehicles are also important forms of integration with public transport, but no studies have explicitly measured their impact on bicycling levels (USDOT, 1998;)
- The proportion of trips by bicycle increased from 0.75% to 1.76% in Barcelona (Romero, 2008) and from 1.0% to 2.5% in Paris (Nadal, 2007; City of Paris, 2007). In Lyon, bicycle counts increased 75% after implementation of the Velo’v program, with bicycle proportion of trips reaching 2% in 2007 (Bonnette, 2007; Velo’v, 2009). A study of the OYBike in London showed that 40% of users shifted from motorized modes (Noland and Ishaque, 2006).
- Some cities, even very large cities, have dramatically raised bicycling levels while
also improving bicycling safety. Berlin, for example, almost quadrupled the number of bicycle trips between 1970 and 2001 and doubled the bicycle share of trips from 5% in 1990 to 10% in 2007. In spite of the sharp rise in bicycling, serious injuries in Berlin fell by 38% from 1992 to 2006.
- The two smallest cities shown are both in the US and provide interesting contrasts. In Boulder, Colorado, the share of workers commuting by bicycle rose from 3.8% in 1980 to 6.9% in 2000 and 8.8% in 2006 in response to an aggressive program of bikeway expansion and complementary pro-bicycle measures. By comparison, the share of workers commuting by bicycle in Davis, California fell from 28% in 1980 to 14% in 2000, in spite of extensive bikeways and bike parking. The decline of bicycling to work in Davis is mainly attributable to a sharp increase in long-distance commuting to jobs in other cities in the Sacramento and San Francisco areas. provide some assurance of their rigor.
- At least three studies found differences in facility preferences between men and women, with women generally more attracted to infrastructure with less motor vehicle traf?c (Dill and Gliebe, 2008; Emond et al., 2009; Garrard et al., 2008). However, Emond et al. (2009) note that although women liked low-traf?c streets, they felt less comfortable than men on off-street paths, perhaps because of security concerns.
For more on John Pucher from the Bicycle Transportation Examiner