To add to that, and perhaps more importantly, is human brain's constant reaction time and tunneling of the vision at higher speeds. The former means that you'll

To add to that, and perhaps more importantly, is human brain's constant reaction time and tunneling of the vision at higher speeds. The former means that you'll be travelling a longer distance before being able to react to something like seeing a pedestrian entering the street. The latter narrows your peripheral vision such that looking straight, you won't be able to detect movements on the footpath and crossing streets. EDIT: A famous commercial by NSW government [1] about the difference of 5km/h. [1]: https://www.youtube.com/watch?v=h9VWF1DXQ8s https://www.youtube.com/watch?v=h9VWF1DXQ8s