[vjvj]

This is a fascinating exercise with a disappointing argument and pre-determined conclusion.

The writer notes that higher speed increase likelihood of an injury in the case of an accident. There is no comment on the factors that influence the likelihood of an accident and how these change with speed. By this logic, every road should have a 20mph limit - clearly this would do more harm than good overall.

A better analysis would take into account the utility of all relevant parties (including drivers). This would mean superior solutions such as those that maintain car speed as well as improve cyclist/ped safety could be considered rather than simply constructing an argument to fit one solution the writer has proposed without any evidence that it would even work.

[gozo]

Engineering from first principle tells us that roads where cars interact with unprotected humans should have a limit of 20 mph. I'm not sure if this is such a road but overall, because of physics, speed isn't really up for debate.

Edit: Also really sad to see this get removed, flagged(?), from the front page. It was a really cool hack. HN is all about BS and not technology these days it seems.

[vjvj]

Unfortunately many roads in London have 20mph speed limits now.

They do have a purpose at certain times of day but the inefficiency of doing 20mph when the road, cycle lanes and pavements are largely empty is disappointing.