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Obligatory XKCD: http://xkcd.com/1138/ http://xkcd.com/1138/ In Seattle a few intersections have been singled out as the most dangerous for cyclists because of
by salmonellaeater 13y ago
Obligatory XKCD: http://xkcd.com/1138/ http://xkcd.com/1138/
In Seattle a few intersections have been singled out as the most dangerous for cyclists because of the number of collisions involving cyclists there. Considering they are also the highest-traffic intersections for bicycles, it doesn't actually say anything about how dangerous they are per cyclist-trip.
Crashmapper is useless without knowing how many vehicles pass each intersection per day.
- talos 13y agoUseless for figuring out how absolutely safe an intersection is by specific mode of transit at a specific point in time, sure. There are other uses though, you just have to make sure to take into account the unknown denominator. That's why being able to compare layers and run through time is so important.
- rtfeldman 13y agoRight. For example, if your goal is to reduce total number of crashes, (assuming you are in a position to meaningfully impact this,) the ability to identify "hotspots" is extremely valuable.
- deleted 13y ago[deleted]
- milliams 13y agoHowever, if you want to use it to know where to focus efforts to save the most lives it is useful. It's the correct representation for some uses, just not for all uses.
- jvm 13y agoAlthough even in that case it's important to know both pieces of information. Past some level of safety, intersections likely hit a floor where no amount of further investment will actually make them safer.
- brownbat 13y ago> Past some level of safety, intersections likely hit a floor where no amount of further investment will actually make them safer. That point is probably called "driverless cars."
- seanmcdirmid 13y agoAnd "driverless cycles" probably also.
- anigbrowl 13y agoThat data is easy to sample if necessary, whereas the crash data is not.