Children should be physically active at least 60 minutes a day to remain fit and healthy. De Vries advises urban planners and civil servants to pay more attention to creating a traffic-safe environment in (re)designing neighbourhoods. The construction of additional play areas is insufficient, in her opinion, in stimulating children to be more active. De Vries measured activity levels in 350 pre-schoolers and 500 elementary school pupils by means of activity diaries and high-tech step counters. The majority of these urban children proved to be insufficiently active. This is connected, among other factors, with the traffic infrastructure in their neighbourhoods. Children from neighbourhoods with many pedestrian crossings turned out to walk or cycle to school 3 to 5 times more often than children from neighbourhoods with fewer pedestrian crossings. Activity levels of urban children may also be positively affected by the presence of bicycle paths, pavements, parking spaces and roundabouts. Five out of the ten neighbourhoods studied have by now been redesigned. Repeat measurements will demonstrate whether children have become more physically active as a result of these improvements. Results will be known by July of 2010.