I don't know about worldwide, but in Germany[1] the number of children injured or killed in traffic has been on a downward slope for about 40 years. That includes pedestrians. And despite the fact that number of cars has gone up up up.

Of course parents being more restrictive with their kids may well be one of the reasons why the number has gone down (there are many confounding factors).

[1] and, at first glance, most of Europe https://www.destatis.de/DE/Themen/Gesellschaft-Umwelt/Verkeh... (pages 53 onwards among others)