Based on the study of AAA Foundation this post shares the summary of the original report that might be downloaded by the link below.
The data analyzed in this study were from the NHTSA’s National Automotive Sampling System (NASS) Pedestrian Crash Data Study (PCDS) (PCDS, 2008). The PCDS compiled data from on‐scene and follow‐up investigations of crashes that occurred in Buffalo, NY; Fort Lauderdale, FL; Dallas, TX; Chicago, IL; Seattle, WA; and San Antonio, TX from July 1994 through December 1998 and involved a pedestrian struck by a forward‐moving car, pickup truck, van, or SUV (pickup trucks, vans, and SUVs hereafter are referred to collectively as light trucks) with the first point of contact forward of the top of the vehicle’s A‐pillar.
The sample was restricted to vehicles manufactured within 5 years of the study period (model years 1989–1999). Crashes were excluded from the PCDS if the pedestrian was sitting or lying in the roadway, the striking portion of the vehicle had been modified or damaged previously, the vehicle was involved in other impacts besides that with the pedestrian, or vehicle damage measurements were not obtained within 24 hours of the crash.
The data file contained 549 records of pedestrians struck by vehicles. The sample analyzed for this study comprised 422 pedestrians ages 15 years and older who were struck by a single forward‐moving car or light truck model year 1989–1999 and whose injury severity was known.
Adjusted for age, height, weight, BMI, and type of striking vehicle, and standardized to the distribution of pedestrian age and type of striking vehicle for pedestrians struck in the United States in years 2007–2009, the average risk of severe injury reached 10% at an impact speed of 16 mph, 25% at 23 mph, 50% at 31 mph, 75% at 39 mph, and 90% at 46 mph. Risk of severe injury increased approximately linearly with speed for speeds between 23 mph and 38 mph, with an average increase of 3.2 percentage points (95% Confidence Interval [CI]: 2.7 – 3.8) for each 1 mph increase in impact speed for speeds within this range.
The average adjusted, standardized risk of death reached 10% at an impact speed of 23 mph, 25% at 32 mph, 50% at 42 mph, 75% at 50 mph, and 90% at 58 mph. Risk of death increased approximately linearly with speed for speeds between 32 mph and 50 mph, with an average increase of 2.8 percentage points (95% CI: 2.2 – 3.4) for each 1 mph increase in impact speed for speeds within this range.
Graphs below demonstrate the abovementioned standardized risk of death / risk of severe injury relation to the impact speed.