Pedestrian Injuries
Charles J. DiMaggio; Qixuan Chen; Peter A. Muennig; Guohua Li
(See Injury Epidemiology. 2014, 1:17)
Background: In 2005, the US Congress allocated $612 million for a national Safe Routes to School (SRTS) program to encourage walking and bicycling to schools. We evaluated the effectiveness of a Safe Routes to School Program (SRTS) in controlling pedestrian injuries among school-age children. Methods: Bayesian changepoint analysis of quarterly counts of pedestrian injuries among 5 to 19-year- old children in New York City between 2001 and 2010 during school-travel hours in census tracts with and without SRTS. Overdispersed Poisson modeling for difference in differences following the changepoint. Results: In SRTS-intervention census tracts, a change point in the quarterly counts of injuries was identified in the second quarter of 2008, which was consistent with the timing of the implementation of SRTS interventions. In census tracts with SRTS interventions, the estimated quarterly rates of pedestrian injury per 10,000 population among school-age children during school-travel hours were 3.47 (95% Credible Interval [CrI] 2.67, 4.39) prior to the changepoint, and 0.74 (95% CrI 0.30, 1.50) after the changepoint. There was no change in the average number of quarterly injuries in non-SRTS census tracts . Overdispersed Poisson modeling revealed that SRTS implementation was associated with a 44% reduction (95% Confidence Interval [CI] 87% decrease to 130% increase) in school-age pedestrian injury risk during school-travel hours. Conclusions: Bayesian changepoint analysis of quarterly counts of school-age pedestrian injuries correctly identified the timing of SRTS intervention in New York City. Implementation of the SRTS program in New York City appears to be effective in reducing school-age pedestrian injuries during school-travel hours.
Small-Area Spatiotemporal Analysis of Pedestrian and Bicyclist Injuries in New York City
(See Epidemiology. 26(2): March 2015. )
Background: This study quantifies the spatiotemporal risk of pedestrian and bicyclist injury in New York City at the census tract level over a recent 10-year period, identifies areas of increased risk, and evaluates the role of socioeconomic and traffic-related variables in injury risk. Methods: Crash data on 140,835 pedestrian and bicyclist injuries in 1908 census tracts from 2001 to 2010 were obtained from the New York City Department of Transportation. We analyzed injury counts within census tracts with Bayesian hierarchical spatial models using integrated nested Laplace approximations. The model included variables for social fragmentation, median household income, and average vehicle speed and traffic density, as well as a spatially unstructured random effect term, a spatially structured conditional autoregression term, a first-order random walk-correlated time variable, and an interaction term for time and place. Incidence density ratios, credible intervals, and probability exceedances were calculated and mapped. Results: The yearly rate of crashes involving injuries to “pedestrians” (including bicyclists) decreased 16.2% over the study period, from 23.7 per 10,000 population to 16.2 per 10,000. The temporal term in the spatiotemporal model indicated that much of the decrease over the study period occurred during the first 4 years of the study period. Despite an overall decrease, the model identified census tracts that were at persistently high risk of pedestrian injury throughout the study period, as well as areas that experienced sporadic annual increases in risk. Aggregate social, economic, and traffic-related measures were associated with pedestrian injury risk at the ecologic level. Every 1-unit increase in a standardized social fragmentation index was associated with a 19% increase in pedestrian injury risk (incidence density ratio = 1.19 [95% credible interval = 1.16 – 1.23]), and every 1 standardized unit increase in traffic density was associated with a 20% increase in pedestrian injury risk (1.20 [1.15 – 1.26]). Each 10-mile-per-hour increase in average traffic speed in a census tract was associated with a 24% decrease in pedestrian injury risk (0.76 [0.69 – 0.83]). Conclusions: The risk of a pedestrian or bicyclist being struck by a motor vehicle in New York City decreased from 2001 to 2004 and held fairly steady thereafter. Some census tracts in the city did not benefit from overall reductions or experienced sporadic years of increased risk compared with the city as a whole. Injury risk at the census tract level was associated with social, economic, and traffic-related factors.
National Safe Routes to School program and risk of school-age pedestrian and bicyclist injury
Charles J. DiMaggio; Spiros Frangos; Guohua Li
(See Annals of Epidemiology. 2016 June; 26 (6): 412–417.)
Purpose Safe Routes to School (SRTS) was a federally funded transportation program for facilitating physically active commuting to and from school in children through improvements of the built environment. There is evidence that SRTS programs increase walking and bicycling in school-age children, but their impact on pedestrian and bicyclist safety has not been adequately examined. We investigate the impact and effects of the SRTS program on school-age pedestrian and bicyclist injuries in a nationwide sample in the United States. Methods Data were crash records for school-age children (5–19 years) and adults (30–64 years), in 18 U.S. states for a 16-year period (1995–2010). Multilevel negative binomial models were used to examine the association between SRTS intervention and the risk of pedestrian and bicyclist injury in children aged 5–19 years. Results SRTS was associated with an approximately 23% reduction (incidence rate ratio = 0.77, 95% confidence interval = 0.65–0.92) in pedestrian/bicyclist injury risk and a 20% reduction in pedestrian/bicyclist fatality risk (incidence rate ratio = 0.80, 95% confidence interval = 0.68–0.94) in school-age children compared to adults aged 30–64 years. Conclusions Implementation of the SRTS program appears to have contributed to improving traffic safety for school-age children in the United States.
The Cost-Effectiveness of New York City’s Safe Routes to School Program
Peter A. Muennig; Michael Epstein; Guohua Li; Charles J. DiMaggio
(See American Journal of Public Health. 2013 Jul;104(7):1294-9)
Objective. We evaluated the cost-effectiveness of a package of roadway modifications in New York City funded under the Safe Routes to School (SRTS) program. Methods. We used a Markov model to estimate long-term impacts of SRTS on injury reduction and the associated savings in medical costs, lifelong disability, and death. Model inputs included societal costs (in 2013 US dollars) and observed spatiotemporal changes in injury rates associated with New York City’s implementation of SRTS relative to control intersections. Structural changes to roadways were assumed to last 50 years before further investment is required. Therefore, costs were discounted over 50 consecutive cohorts of modified roadway users under SRTS. Results. SRTS was associated with an overall net societal benefit of $230 million and 2055 quality-adjusted life years gained in New York City. Conclusions. SRTS reduces injuries and saves money over the long run.
Charles J. DiMaggio; Joanne E. Brady; Guohua Li
(See Injury Epidemiology. 2015. 2:15)
Background Safe Routes to School (SRTS) is a federally funded transportation program for facilitating physically active commuting to and from school in children through improvements of the built environment, such as sidewalks, bicycle lanes, and safe crossings. Although it is evident that SRTS programs increase walking and bicycling in school-age children, their impact on pedestrian and bicyclist injury has not been adequately examined. Methods We analyzed quarterly traffic crash data between January 2008 and June 2013 in Texas to assess the effect of the SRTS program implemented after 2009 on school-age pedestrian and bicyclist injuries. Results The annualized rates of pedestrian and bicyclist injuries between pre- and post-SRTS periods declined 42.5% (95% confidence interval (CI) 39.6% to 45.4%) in children aged 5 to 19 years and 33.0% (95% CI 30.5% to 35.5%) in adults aged 30 to 64 years. Negative binomial modeling revealed that SRTS intervention was associated with a 14% reduction in the school-age pedestrian and bicyclist injury incidence rate ratio (IRR 0.86, 95% CI 0.75 to 0.98). The effect of the SRTS intervention on pedestrian and bicyclist fatalities was similar though smaller in magnitude and was not statistically significant (adjusted IRR 0.90, 95% CI 0.67 to 1.21). Conclusions These results indicate that the implementation of the SRTS program in Texas may have contributed to declines in school-age pedestrian and bicyclist injuries.
Roadway Characteristics and Pediatric Pedestrian Injury
Charles J. DiMaggio; Guohua Li
(See Epidemiologic Reviews. 2012 Jan; 34(1):46-56)
Changing the built environment is a sound, but often underutilized approach to injury control. The authors reviewed the literature and conducted a meta-analysis to synthesize the evidence on the association of roadway characteristics with risk of pediatric pedestrian injury. To synthesize the data, they converted results to odds ratios based on direct results or abstracted outcomes and used Bayesian meta-analytic approaches by modeling outcomes as the logit of a normally distributed set of outcomes with vague prior distributions for the central measure of effect and its variance. On the basis of 10 studies of roadway features restricted exclusively to pediatric populations, the synthesized effect estimate for the association of roadway characteristics with pedestrian injury risk was 2.5 (95% credible interval: 1.8, 3.2). The probability of a new study showing an association between the built roadway and pediatric pedestrian injury was nearly 100%. The authors concluded that the built environment is directly related to the risk of pedestrian injury. This review and meta-analysis suggests that even modest interventions to the built roadway environment may result in meaningful reductions in the risk of pediatric pedestrian injury.
The Association of Light Trucks and Vans with Pediatric Pedestrian Deaths
Charles J. DiMaggio; Maureen Durkin; Lynne D. Richardson
(See Int J Injury Contr and Safety Prom 2006; 13(2): 95-99.)
We investigated the hypothesis that relative to cars, light trucks and vans (including sports utility vehicles) are more likely to result in fatal pediatric pedestrian injury. It was further hypothesized that this increased risk is a result of head injuries. The study sample consisted of 18,117 police records of motor vehicles involved in crashes in which one or more pedestrian aged 5 to 19 years old was injured or killed. Frequencies and case fatality ratios for each vehicle body type were calculated. We conducted a logistic regression analysis with light truck or van versus car as the exposure variable and fatal / non-fatal pedestrian injury as the outcome variable. After controlling for driver age, driver gender, vehicle weight, road surface condition and presence of head injury, 5 to 19 year-olds struck by light trucks or vans were more than twice as likely to die than those struck by cars (OR = 2.3 95% CI 1.4, 3.9). For the 5 to 9 year-old age group, light trucks and vans were four times as likely to be associated with fatal injury (OR = 4.2 95 % CI 1.9, 9.5). There was an association between head injury and light trucks and vans (OR=1.2, 95% CI 1.1, 1.3). We conclude that vehicle body type characteristics play an important role in pediatric pedestrian injury severity and may offer engineering-based opportunities for injury control.
Child Pedestrian Injury in an Urban Setting: Descriptive Epidemiology
Charles J. DiMaggio; Maureen Durkin
(See Academic Emergency Med. 2002; Jan 9(1): 54-62.)
This study describes the epidemiology of pedestrian injuries to children and adolescents (ages <20) in an urban setting, providing analyses of environmental and pedestrian variables. Anonymous data were obtained for all motor vehicle crashes occurring in New York City over a 7-year period (1991-1997). Among 693,283 crashes, 97,245 resulted in injuries to 100,261 pedestrians of whom 32,578 were under age 20. Using census counts for the denominator, the overall incidence of pediatric pedestrian injuries was 246/100,000 per year, and the case fatality rate was 0.6%. Incidence rates peaked in the 6-14 year age group, and showed a modest annual decline during the study period. Younger children were more likely to be struck mid-block and during daylight hours, whereas adolescents were more likely to be struck at intersections and at night. For younger children, there was a sharp peak in incidence during the summer months. Road and weather conditions did not appear to affect injury risk. These results help identify priorities for child pedestrian injury prevention and education, inform public health policy, and direct emergency medical health services resource allocation.
Pedestrian Injuries and Fatalities in Nassau County
In an effort to identify and describe factors that contribute to the occurrence and severity of pedestrian injuries in Nassau County, the department of health analyzed data on pedestrian injury incidence, hospitalization and fatality. There were 9,284 pedestrian injuries and 299 pedestrian deaths in Nassau County Between 1991 and 2000, for an average of 928 injuries and 30 deaths per year. Annual injury and fatality rates were constant over the 10 year period. Pedestrian incidents accounted for only 2% of all traffic-related injuries, but were responsible for 27% of all traffic-related deaths. Overall there was an increase in pedestrian injuries over the winter months, but children were more likely to be injured in late spring and summer. The average age of an injured pedestrian was 37, but the greatest numbers of injured pedestrians were aged 16. Most injuries occurred during daylight hours, but there was some evidence of an increased risk of fatality at night. 26% of pedestrians injured at intersections were crossing with the signal. There was an association between racial, ethnic and economic variables and the risk of hospitalization for pedestrian injury in a community. A geographic information system was created to identify the sites of multiple pedestrian injuries and fatalities on county roads and to help inform engineering, educational and enforcement efforts