• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of injprevInjury PreventionVisit this articleVisit this journalSubmit a manuscriptReceive email alertsContact usBMJ
Inj Prev. Sep 2003; 9(3): 205–209.
PMCID: PMC1731007

Safety in numbers: more walkers and bicyclists, safer walking and bicycling


Objective: To examine the relationship between the numbers of people walking or bicycling and the frequency of collisions between motorists and walkers or bicyclists. The common wisdom holds that the number of collisions varies directly with the amount of walking and bicycling. However, three published analyses of collision rates at specific intersections found a non-linear relationship, such that collisions rates declined with increases in the numbers of people walking or bicycling.

Data: This paper uses five additional data sets (three population level and two time series) to compare the amount of walking or bicycling and the injuries incurring in collisions with motor vehicles.

Results: The likelihood that a given person walking or bicycling will be struck by a motorist varies inversely with the amount of walking or bicycling. This pattern is consistent across communities of varying size, from specific intersections to cities and countries, and across time periods.

Discussion: This result is unexpected. Since it is unlikely that the people walking and bicycling become more cautious if their numbers are larger, it indicates that the behavior of motorists controls the likelihood of collisions with people walking and bicycling. It appears that motorists adjust their behavior in the presence of people walking and bicycling. There is an urgent need for further exploration of the human factors controlling motorist behavior in the presence of people walking and bicycling.

Conclusion: A motorist is less likely to collide with a person walking and bicycling if more people walk or bicycle. Policies that increase the numbers of people walking and bicycling appear to be an effective route to improving the safety of people walking and bicycling.

Full Text

The Full Text of this article is available as a PDF (152K).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Murray CJ, Lopez AD. Mortality by cause for eight regions of the world: Global Burden of Disease Study. Lancet. 1997 May 3;349(9061):1269–1276. [PubMed]
  • Murray CJ, Lopez AD. Global mortality, disability, and the contribution of risk factors: Global Burden of Disease Study. Lancet. 1997 May 17;349(9063):1436–1442. [PubMed]
  • Nantulya Vinand M, Reich Michael R. The neglected epidemic: road traffic injuries in developing countries. BMJ. 2002 May 11;324(7346):1139–1141. [PMC free article] [PubMed]
  • Runge Jeffrey W, Cole Thomas B. Crosswalk markings and motor vehicle collisions involving older pedestrians. JAMA. 2002 Nov 6;288(17):2172–2174. [PubMed]
  • Mohan Dinesh. Road safety in less-motorized environments: future concerns. Int J Epidemiol. 2002 Jun;31(3):527–532. [PubMed]
  • Leden L, Gårder P, Pulkkinen U. An expert judgment model applied to estimating the safety effect of a bicycle facility. Accid Anal Prev. 2000 Jul;32(4):589–599. [PubMed]
  • Leden Lars. Pedestrian risk decrease with pedestrian flow. A case study based on data from signalized intersections in Hamilton, Ontario. Accid Anal Prev. 2002 Jul;34(4):457–464. [PubMed]
  • Dhillon PK, Lightstone AS, Peek-Asa C, Kraus JF. Assessment of hospital and police ascertainment of automobile versus childhood pedestrian and bicyclist collisions. Accid Anal Prev. 2001 Jul;33(4):529–537. [PubMed]
  • McCarthy M. The benefit of seat belt legislation in the United Kingdom. J Epidemiol Community Health. 1989 Sep;43(3):218–222. [PMC free article] [PubMed]
  • Roberts I, Campbell F, Hollis S, Yates D. Reducing accident death rates in children and young adults: the contribution of hospital care. Steering Committee of the Major Trauma Outcome Study Group. BMJ. 1996 Nov 16;313(7067):1239–1241. [PMC free article] [PubMed]
  • Li G, Shahpar C, Grabowski JG, Baker SP. Secular trends of motor vehicle mortality in the United States, 1910-1994. Accid Anal Prev. 2001 May;33(3):423–432. [PubMed]

Articles from Injury Prevention are provided here courtesy of BMJ Group


Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


  • PubMed
    PubMed citations for these articles

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...