I’m all for everything else on your list, and I’m all in favor of protecting the children, but I draw the line at increasing the surveillance state. Big Brother gets to watch enough of what we do, already. Let’s not give him even more eyes.

This one wasn't off-topic, but it didn't really add anything. One of your other ones was off-topic, switching from driver risks to cycling risks, which had nothing to do with the article or the preceeding comments.

"Imagine we had the technology to reduce childhood cancer rates by 50%, but chose not to use it."

This is literally the case with traffic deaths today. About 45% of traffic fatalities are due to not wearing a seat belt. The technology has existed for decades but people choose not to use it. This then overstates the risks in the high level stats for the people who do use seatbelts. The number of childhood fatalities not buckled in was about 30-35%, and childhood restraint misuse is between 80-90%. If we want to make improvements in child survivability, then we should start by utilizing the most effect safety systems for the biggest focused gains.

"Traffic accidents kill more children than cancer. And we have the technology to reduce them: GPS-based speed limiters, automatic breaking system, speed bumps, red light cameras."

There is resistance to this because of the overstated risks, feasibility of implementation, and questions of effectiveness. For example, red light cameras have been shown to increase accidents because of the funding contracts many use. It's odd that you leave off enhanced driver testing when this is one of the most universal benefits. That and stricter enforcement are some of the main causes for lower fatality rates in many European nations, even in unrestricted speed sections of roads.

"Yet we choose not to act because ... people think that would be too uptight?"

No, that's more of a strawman than reality.