the Y. Likewise, X chromosomes spend 2/3 of their time in females, and should be selected to produce female-biased sex ratios. Hamilton marshaled the evidence supporting biased sex ratios caused by genes on the sex chromosome. Because autosomes continue to favor a balanced sex ratio, the important implication is that individuals do not always have indivisible interests — instead there can be co...

road safety must be shared responsibility between the school, the parents/caregivers, the children, territorial authority, transport agencies, and police. children need to learn to use the roads safety, to walk and cycle in safety, and also to use their common sense when crossing a road or getting into a car. road safety is essential for children’s freedom, development, and exercise and of cour...

Walking, as an important transportation mode, plays a large part in urban transportation systems. This mode is of great importance for planners and decision-makers because of its impact on environmental and health aspects of communities. However, this mode is so complex in nature that makes it difficult to study or model. On the other hand, chaos theory studies complex dynamical nonlinear syste...

Stream sedimentation concerns might probably be incorporated into the road design process as a simplified, intuitive thumbnail model. Road Density (RD) and Stream Crossing Density (SCD) however guide designers towards minimizing minor, unused spur roads that have minimal sediment impacts. Crossing Area Served (CAS) on the other hand, focuses design attention towards the most heavily traveled se...

Past research has shown that road users accept shorter time gaps when the waiting time/number of vehicles they let pass before attempting to merge into the traffic increases. While elderly pedestrians are known to be an extremely vulnerable group of road users, very few studies dealt with the effect of environmental constraints and crossing complexity on this population's safety. The present st...

Social information use is common in a wide range of group-living animals, notably in humans. The role it plays in decision-making could be a key to understanding how social groups make collective decisions. The observation of road-crossing behaviours in the presence of other individuals is an ideal means to study the influence of social information on decision-making. This study investigated th...

About 54% of pedestrians killed on French roads are over 60 years old (ONISR, 2012), whereas this age group represents less than 24% of the French population (INSEE, 2013). Factors such as slowdown of decision-making, reduction of walking speed, and difficulty of adopting sufficient safety margins can explain that over-representation of older pedestrians in traffic accidents (e.g. Lobjois & Cav...

Risk-sensitive adaptive spatial organisation during group movement has been shown to efficiently minimise the risks associated with external ecological threats. Whether animals can draw on such behaviours when confronted with man-made threats is generally less clear. We studied road-crossing in a wild, but habituated, population of meerkats living in the Kalahari Desert, South Africa. We found ...

OBJECTIVE Pedestrian injuries are a major cause of morbidity and mortality to children, especially boys. Adults serve as pedestrian role models and provide learning opportunities for children when walking to school. The research objectives were to investigate adult pedestrian behavior when accompanying boys and girls. METHODS Behavioral observation of 140 adult pedestrians accompanying 4- to ...