title: Measures of exposure to road traffic injury risk.
abstract: OBJECTIVE
  To compare the risk of road traffic injury calculated using an exposure measure based on people's mobility, person-hours travelled (person-hours), with the risk obtained using population census, vehicle fleet and vehicle-kilometres travelled.
  
  
  METHODS
  The rate of road traffic injury on a working day in Catalonia in 2006 was calculated using the number of people injured from the Register of Accidents and Victims of the National Traffic Authority and as denominator: person-hours travelled, from the 2006 Daily Mobility Survey of Catalonia; population census and vehicle fleet, from the National Statistics Institute; and vehicle-kilometres, from the Ministry of Public Works.
  
  
  RESULTS
  Compared with person-hours travelled: population census may underestimate the risk in groups with low mobility; vehicle-kilometres may underestimate the risk in regions with high level of non-motorised mobility and high use of public transport; vehicle fleet may underestimate the risk for collective forms of transport such as buses and for motorcyclists who make many trips but of short duration.
  
  
  CONCLUSIONS
  Measures of exposure involving people's mobility should be used in the estimation of road traffic injury risk, instead of vehicle's mobility, population census or vehicle fleet.
authors: Agència de Salut Pública de Barcelona (ASPB), CIBER Epidemiología y Salud Pública (CIBERESP), Institut d'Investigació Biomèdica (IIB Sant Pau), , Barcelona, Spain.
authors: Elena
authors: E
authors: Santamariña-Rubio
authors: Katherine
authors: K
authors: Pérez
authors: Marta
authors: M
authors: Olabarria
authors: Ana M
authors: AM
authors: Novoa
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D001334:Automobile Driving / Q000706:statistics & numerical data*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D014947:Wounds and Injuries / Q000453:epidemiology*; D055815:Young Adult