Almost all locomotor animals respond to visual looming or to discrete changes in optical size. The need to detect and process looming remains critically important for humans in everyday life. Road traffic statistics confirm that children up to 15 years old are overrepresented in pedestrian casualties. We demonstrate that, for a given pedestrian crossing time, vehicles traveling faster loom less than slower vehicles, which creates a dangerous illusion in which faster vehicles may be perceived as not approaching.
Bicycling in cities is booming, for many reasons: health and environmental benefits, time and cost savings, more and better bike lanes and paths, innovative bike sharing programs, and the sheer fun of riding. City Cycling offers a guide to this urban cycling renaissance, with the goal of promoting cycling as sustainable urban transportation available to everyone.
The first edition of Collection of Cycle Concepts was published in 2000 and enjoyed a wide circulation among everyone interested in bicycle traffic. The simultaneous publication of the English version spread the Danish bicycle traffic experience to many parts of the world.
The second edition, Collection of Cycle Concepts 2012, updates the field, featuring new challenges and the latest knowledge.
This article seeks to answer the question whether mandatory bicycle helmet laws deliver a net societal health benefit. The question is addressed using a simple model. The model recognizes a single health benefit – reduced head injuries, and a single health cost – increased morbidity due to foregone exercise from reduced cycling. Using estimates suggested in the literature of the effectiveness of helmets, the health benefits of cycling, head injury rates, and reductions in cycling, leads to the following conclusions.
