I've thought about doing something like that but I'm not sure if the plastic wheels and gear box can handle it, and I'm not sure how much more effort I want to

I've thought about doing something like that but I'm not sure if the plastic wheels and gear box can handle it, and I'm not sure how much more effort I want to invest in a limited platform. In the situations he's in now, anticipation is just as good as brakes; being able to see that he's going to run into a person or obstacle and slowing down is what I'm aiming for. In a "racing" situation, braking is necessary to slow down from high speed quickly in order to take a corner without losing traction, but the plastic wheels already have so little traction that we would exceed the performance envelope of the wheels before really getting much speed advantage out of it. Probably what I'll do is upgrade to a basic electric kart at the next birthday and leave this car as it is for Sunday driving and/or the next kid (it'll be easy to reduce the power again by reducing the number of batteries)