Archive for March, 2010

London Bike Plan FAIL

It is good to know that American city planners aren’t the only ones striping really dangerous and dysfunctional bike lanes.

Merely putting blue paint on low quality infrastructure will not result in a boom in cycling. The majority need cycling to both feel safe and be convenient before they will take part.

The entire blog post is well worth reading as many of the problems cited apply to sucky bike plans in the US too.

Extremely substandard width bike lanes, with no buffer from traffic, even though the roadway is plenty wide enough. London planners are preserving existing automobile LOS rather than provide world-class cycle facilities.

Oh my. Bike path routed through bus stop, with bollards in the bike lane.

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Colorado Helmet Bill

Colorado’s House of Representatives has just passed a bicycle helmet bill. And as is often the case with these kinds of bills, Legislators heard anecdotes from accident victims’ about how “my helmet saved my life.

Despite opposition from those saying it needed a punitive component, a bill proposed by a Fort Collins lawmaker that would require children to wear helmets while on bicycles, skateboards and the like took an initial step Tuesday toward becoming a law.

And Fort Collins teenager Amanda Miyoshi’s testimony before the House Transportation and Energy Committee was a large reason why the lawmakers approved the bill with a 7-2 vote.

“It was some of the most moving testimony I’ve heard so far this year,” said Rep. Liane McFadyen, D-Pueblo, and the committee chair.

Miyoshi shared the story of how she survived a 2007 collision with a car while she was riding her bicycle to Fort Collins High School. Miyoshi was wearing a helmet, but she still suffered a traumatic brain injury.

“Since my accident in 2007, two other girls in Fort Collins have been hit by cars, and their outcomes have not been nearly as positive as mine,” the 18-year-old Miyoshi said during her testimony. “A traumatic brain injury is bad enough, but I lived through my accident because I was wearing a helmet.”

Amanda is certainly lucky to be alive. But it is quite improbable that her bike helmet had anything to do with it.

The CPSC standard for bicycle helmets specifically states that it does not protect against collisions with “3rd party” objects (i.e. automobiles). Due to their heavy weight, the kinetic energy of automobile collision is extraordinarily high. Bike helmets undergo no tests for kinetic energy levels of that magnitude. Nor do the simplistic tests attempt to model complex dynamics of a motor vehicle collision.

Amanda’s case is particularly noteworthy because the collision occurred directly outside a school, where traffic engineers built a 40mph 4-lane divided highway. Traffic engineers expected students to dash across the highway without benefit of any traffic control devices or grade separation. Rather than address fundamental traffic engineering deficiencies in Colorado, the Legislature’s solution is mandatory “safety” helmets for students.

BTW, since the issue of bike helmets has come up previously in SF, this is a good opportunity to review some data.

The definitive study is “No clear evidence from countries that have enforced the wearing of helmets,” Robinson British Medical Journal 2006; 332: 722-725. Robinson analyzed crash data in Australia after that country passed mandatory helmet laws for both adults and children. Within a year, helmet utilization rates had more than doubled. If helmets were anywhere near as effective as claimed by proponents, there should have been dramatic reduction in fatalities and traumatic head injuries. In fact, no such reduction was observed.

The statistical power of detecting effects of a helmet law is proportional to the change in percentage helmet wearing (%HW). If %HW increases by 50 percentage points (e.g. from 35%-85% of cyclists) and (as suggested by case-control studies) helmets prevent 68% of head injuries (HI), HI rates should fall by 46%. Changes this large would be evident in times series. The selection criterion for inclusion was therefore an increase in %HW of at least 40 percentage points in less than 1 year.

Some may have noticed in the above graph that the overall number of bicycle injuries (head injury and non-head injury) did decline after the helmet law went into effect. Robinson attributes this to: 1. Decline in total number of bicyclists, and 2. Other road safety measures.

See also

Helmet laws and cycle use

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