Pedestrian crashes: higher injury severity and mortality rate for light truck vehicles compared with passenger vehicles

Introduction: During the last two decades changes in vehicle design and increase in the number of the light truck vehicles (LTVs) and vans have led to changes in pedestrian injury profile. Due to the dynamic nature of the pedestrian crashes biomechanical aspects of collisions can be better evaluated in field studies. Design and settings: The Pedestrian Crash Data Study, conducted from 1994 to 1998, provided a solid database upon which details and mechanism of pedestrian crashes can be investigated. Results: From 552 recorded cases in this database, 542 patients had complete injury related information, making a meaningful study of pedestrian crash characteristics possible. Pedestrians struck by LTVs had a higher risk (29%) of severe injuries (abbreviated injury scale ⩾4) compared with passenger vehicles (18%) (p = 0.02). After adjustment for pedestrian age and impact speed, LTVs were associated with 3.0 times higher risk of severe injuries (95% confidence interval (CI) 1.26 to 7.29, p = 0.013). Mortality rate for pedestrians struck by LTVs (25%) was two times higher than that for passenger vehicles (12%) (p<0.001). Risk of death for LTV crashes after adjustment for pedestrian age and impact speed was 3.4 times higher than that for passenger vehicles (95% CI 1.45 to 7.81, p = 0.005). Conclusion: Vehicle type strongly influences risk of severe injury and death to pedestrian. This may be due in part to the front end design of the vehicle. Hence vehicle front end design, especially for LTVs, should be considered in future motor vehicle safety standards

Child car restraints: Mandating type and seating row according to age with positive effect in regional city in Queensland, Australia

Road trauma is a leading cause of child injury worldwide. In highly motorised countries, injury as a passenger represents a major proportion of all child road deaths and hospitalisations. Australia is no exception, particularly since there are high levels of private motor vehicle travel to school in most Australian states. Recently the legislation governing the type of car restraints required for children aged under 7 years has changed in Australia, aligning requirements better with accepted best practice. However, it is unclear what effect these changes have had on children’s seating positions or the types of restraints used. A mixed methods evaluation of the impact of the new legislation on compliance was conducted at three times: baseline (Time 1); after announcement that changes were going to be implemented but before enforcement began (Time 2); and after enforcement commenced (Time 3). Measures of compliance were obtained using two methods: road-side observations of vehicles with child passengers; and parental self-report (intercept interviews conducted at Time 2 and Time 3 only). Results from the observations suggested an overall positive effect. Proportions of children occupying front seats decreased overall and use of dedicated child seats increased to almost 40% of the observed children by Time 3. However, almost a quarter of the children observed still occupied front seats. These results differed from those of the interview study where almost no children were reported as usually travelling in the front seat, and reported use of dedicated restraints with children was almost 90%, over twice that of the observations

DNA Photocleavage in the Near-Infrared Wavelength Range by 2-Quinolinium Dicarbocyanine Dyes

Here, we report the syntheses of two pentamethine cyanine dyes containing quinolinium rings and substituted with either hydrogen (3) or bromine (4) at the meso carbon. The electron withdrawing bromine atom stabilizes dye 4 in aqueous buffer, allowing complex formation to occur between the dye and double-helical DNA. UV&ndash;visible, CD, and fluorescence spectra recorded at low DNA concentrations suggest that dye 4 initially binds to the DNA as a high-order aggregate. As the ratio of DNA to dye is increased, the aggregate is converted to monomeric and other low-order dye forms that interact with DNA in a non-intercalative fashion. The brominated dye 4 is relatively unreactive in the dark, but, under 707&ndash;759 nm illumination, generates hydroxyl radicals that cleave DNA in high yield (pH 7.0, 22 &deg;C). Dye 4 is also taken up by ES2 ovarian carcinoma cells, where it is non-toxic under dark conditions. Upon irradiation of the ES2 cells at 694 nm, the brominated cyanine reduces cell viability from 100 &plusmn; 10% to 14 &plusmn; 1%. Our results suggest that 2-quinolinium-based carbocyanine dyes equipped with stabilizing electron withdrawing groups may have the potential to serve as sensitizing agents in long-wavelength phototherapeutic applications

An analysis of head impact severity in simulations of collisions between pedestrians and SUVs/work utility vehicles, and sedans

Objective: To describe the determinants of the severity of the head kinematics of a pedestrian when struck by common sport utility vehicles (SUV) and work utility vehicles (WUVs) to assess how effective assessment protocols are in assessing injury risk for SUVs and work utilities. Methods: Three hundred twenty-four simulations of pedestrian collisions with SUVs, work utility vehicles, and sedans were performed using several vehicle geometries, pedestrian orientations, speeds, and braking levels. Contact stiffnesses in the models were based on impact test results with exemplar vehicle structures. A single contact characteristic was used for all head-to-hood contacts to allow the effects of other factors on head injury risk to be compared. Simulations of standard headform tests on the same hood characterized the structure from a subsystem test perspective. Results: Head injury criterion values were higher in SUV/WUV simulations than sedan simulations because of high neck tension rather than through higher contact forces with the hood. In fact, the severity of the impact between the head and hood was slightly less in SUV/WUV simulations. Sedan and SUV/WUV simulations produced lower head injury criterion (HIC) values than did the subsystem tests. Conclusions: High bonnet leading edges led to increased neck loads in these simulations of pedestrian collisions. Neck loads were influential on head injury risk in the SUV/work utility simulations but not in sedan simulations. Subsystem impact tests may overestimate head impact risk from the hood itself but fail to capture a potentially important injury mechanism in collisions with vehicles with high leading edges and thus fail to differentiate completely risks posed by such vehicles. These results may have implications for the interpretation of pedestrian subsystem test results: a given HIC value in an SUV/WUV test may represent a relatively higher risk of injury than the same results recorded in a sedan test.Robert W. G. Anderson and Samuel Doeck