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  1. Barry Pless
  1. Correspondence to Dr Barry Pless, Westmount, Quebec, Canada H3Y2V2; barry.pless{at}

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Helmet legislation: effects on cycling

I recently became aware of an impressive body of work that is less often cited than it should be when debating the effects of bicycle helmet legislation. As well as providing strong support for the effectiveness of helmets, it also helps counter the argument that ridership is reduced by legislation. Those opposed to helmet laws constantly refer to Robinson (some of whose work was published in this Journal). However, overlooked are a series of apparently flawless studies by Jake Olivier, a statistician, and his colleagues in New South Wales, Australia. I urge readers interested in this issue to at least read those listed below. In a nutshell, Olivier reminds us that in 1994, Marshall and White found no evidence of a significant change in ridership before and after the law, regardless of age. He also notes that the Australian ride-to-work survey before and after legislation showed a bike riding change from a little over 1% to a little under 1%, which he describes as ‘statistically indistinguishable from a horizontal line.’ In Australian capitals, 1.14% cycled to work in 1986, and 1.13% did so in 1991 (postlegislation for most of Australia).;;;

Too stoned to drive

Now that Colorado has legalised marijuana, it must decide what laws to apply to drivers who are ‘over the limit’. Choosing a level is not easy, however, because (it is argued) ‘marijuana … affects the body differently than alcohol.’ One view is that regulations ‘… should err on the side of safety for the travelling public.’ The counterview is that ‘setting a tetrahydrocannibinol (THC) limit would free prosecutors from having to prove their cases’. All that seems clear is that smoking pot affects spatial perceptions and thus increases risk. At present, legal limits range from 0 to 5 ng/ml.

US air traffic controller errors increase

It appears that errors by …

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  • Provenance and peer review Commissioned; internally peer reviewed.