Meanwhile I am assuming that the tendency of mechanical progress is to make life safe and soft. This may be disputed, because at any given moment the effect of some recent mechanical invention may appear to be the opposite. Take for instance the transition from horses to motor vehicles. At a first glance one might say, considering the enormous toll of road deaths, that the motor-car does not exactly tend to make life safer. Moreover it probably needs as much toughness to be a first-rate dirt-track rider as to be a broncho-buster or to ride in the Grand National. Nevertheless the tendency of all machinery is to become safer and easier to handle. The danger of accidents would disappear if we chose to tackle our road- planning problem seriously, as we shall do sooner or later; and meanwhile t
