[hyper_reality]

This map looks cool but it doesn't tell us a lot about the safe and unsafe places to cycle in London. Because it's based on collision data by location, but we don't know how many people cycle on each road per year, so can't normalise for that.

To compare two examples, you can pick out Richmond Park in south-west London due to the low number of collisions in it. But this is actually a highly popular location to cycle. The relatively low amount of vehicles, 20mph speed limit, ban on large vehicles, high visibility, and few junctions, makes it a great place to cycle.

There are also a low number of collisions in the boroughs of Bromley and Bexley in south-east London. But this is not because they're safe, but because very few people cycle there. There are loads of fast roads in these boroughs and little cycle infrastructure, and more of an hostile attitude from drivers compared to many other places in London.

[ageitgey]

Not to pick on the original post, but one of my all-time biggest data pet peeves is map diagrams that aren't normalized by population/some kind of denominator. They all end up as slightly janky population maps with weird anomalies that only make sense if you know the true denominator anyway.

To your point, Kew Gardens and Richmond Park both show up with blank hexagons on the map. But Kew Gardens doesn't allow bike traffic while Richmond Park is full of bikes.

Side note: As someone who lives by Richmond Park and visits often, I wouldn't be surprised if there are more bike vs. deer accidents than bike vs. car accidents.

[hutattedonmyarm]

> Not to pick on the original post, but one of my all-time biggest data pet peeves is map diagrams that aren't normalized by population/some kind of denominator. They all end up as slightly janky population maps with weird anomalies that only make sense if you know the true denominator anyway.

Of course, there is a relevant XKCD

https://xkcd.com/1138/

[mFixman]

Bromley is actually a fantastic borough for cycling: mostly rural, great walking/cycling trails, good rail connections for the way back, and it even has weird Victorian era dinosaurs in Crystal Palace Park.

Why cycling's not more popular there is a mystery to me.

[bertil]

There must be datasets of cyclist activity in London. BeeLine is a private company that develops a device for cyclists to orient themselves; I know they worked on cleaning up relevant data. Not sure if they would be keen to share with the author.