The over four thousand pedestrians killed ever year from motor vehicle collisions have motivated the following graphic.
Naturally, we expect the likelihood of mortality to increase as the vehicle travels faster and physics suggests that it will be nonlinear. But like anything else, we want to make decisions based on accurate information and understanding of risk.
These estimates originate from research using 1980s and earlier data more likely to report serious injuries. From the abstract of a literature review published in 2011.
Without exceptions, papers written before 2000 were based on direct analyses of data that had a large bias towards severe and fatal injuries. The consequence was to overestimate the fatality risks. We also found more recent research based on less biased data or adjusted for bias. While still showing a steep increase of risk with impact speed, these later papers provided substantially lower risk estimates than had been previously reported.
|Rosen and Sander (2009)|
We can see the bias in this graph by Rosen. You can see how the risk curves are dramatically shifted left when using the biased data.