People move through cities in whatever mode of transportation gets them from point A to point B efficiently. Car focussed developments restrained people’s freedoms by focussing only one form of transport, today cities need to incorporate as many forms of movement as possible. To help with this transition speed limits in cities ought to be limited to 30km/h. At that speed car drivers are less likely to kill with their vehicles and thereby ensure a safer city for all. What’s more it makes non-car based transit more efficient and thus reduces a city’s carbon footprint. There are so many benefits to limiting how fast a metal box can go!
When it comes to urban travel, 20 mph is a kind of magic number. It is under most scenarios the natural limit of how fast people can move through dense urban areas at an average clip. The New York City subway, which can and will go 55 mph on long straightaways—like the run on the 2 or 3 line from Times Square to 72nd Street—travels at an average speed of about 17 mph when taking into account time spent at stops, slowing down for curves, and the occasional delay due to train traffic ahead of us (other systems go faster, but they tend to be ones with longer distances between stops serving primarily suburban commuters; but by way of comparison, the London Underground’s average speed is, you guessed it, 20 mph). The average urban biking speed is something like six miles per hour when factoring in stops, but closer to 11 to 18 mph when in movement. E-bikes—which have the potential to revolutionize urban transportation and already have in many global cities—typically have a top speed right around 20 mph.