Here are some strong reasons why we should be concerned about Henderson's paper. Henderson Ignores Safer Cycling Environment Henderson uses the growth worldwide of bicycle sales in comparison to car sales over the last 20 years and fatality rates to show that he believes there is a cycling problem. Although his point is unclear, he seems to be saying that the decline in the fatality rate of cyclists among the population should have matched the fatality rates of other road users. Such a comparison and any conclusion derived from it would be erroneous because it is based on rates among the population, not cycle usage. Besides a slower fall in the cyclist fatality rate is to be expected given that the number of cyclists among the population is increasing faster than other road user groups, and given that some groups may not be increasing at all, for example pedestrians.
Evidence suggests that walking is declining as population switches to car use.
Henderson's interpretation of the statistics he presents conceals the much greater problem for society, which is the large number of head injury fatalities among motor vehicle users. Laboratory tests show that a bicycle helmet provides protection to parts of the head in a narrow range of impact velocities. It matters little whether an impact in that range occurs when the helmet wearer is on a bicycle or in a motorvehicle. If Henderson's case for universal helmet use for cyclists, based on a reduced fatalities, could be upheld, then there would be a better case by a factor of 10 to support universal helmet use for car users. It is not for us to pursue that one, but we are overjoyed that Henderson's statistics reveal that cycling is increasing at the same time as cyclist fatality rate is falling.