@skyfaller @bikenite A7. I've taken many precautions, though am not sure about their efficacy:
* I made flag pole lights. Pickup trucks have hoods that are 5+ feet tall and I needed something tall for visibility for me and my kid on their own bike.
* I have also ridden with a flag and a koinobori fish streamer.
* Loud music can help make sure others are aware of your presence, but your kid might not like that at all
* Bubble machines are fun and I believe that drivers give you more space because they might not like getting bubbles on their windshield (soap!)
* Sometimes I'd run lights during the daytime also
* I have a camera that I mount on a selfie stick to record our Bike Buses. I think it also makes drivers slow down or drive more safely because they either don't know what it is but it looks *weird* or they know it's a camera and know that they might be recorded if they do anything unsafe

Hope that helps! We have been car-free, riding with child for more than a decade.

#BikeNite