In the 1970s, most children took themselves to school. The past is another land and people live there differently. The congestion now within a kilometre of a primary school confirms that most children are chauffeured to school. Here is one study on active travel on the topic.
Active travel data for the ACT.
Only about a third of children walk or cycle to school. It does not change much with age and saw small increases since 2007 to 2016 (see graph below). The ACT Government at one stage put a primary school within walking distance in every suburb. Now with the rise of mega-schools this is less common.