Here's a concise version that incorporates your personal story, the statistics, and a clear solution:

As a father of four boys under 10, I've seen how dangerous parking lots can be for children. When kids get excited, they sometimes run ahead without realizing the risks. They are small, difficult for drivers to see, and often hidden behind parked vehicles.

Every week in America, approximately 110 children are hit by vehicles in parking lots and driveways, and more than 5,000 children are injured each year in non-traffic areas such as parking lots and private property. Yet most parking lots still force pedestrians to walk directly behind backing cars with no protected path.

We build sidewalks on our streets and protected lanes for cyclists. It's time to bring the same safety-first thinking to parking lots.

This petition calls for protected pedestrian walkways to be included in all new commercial parking lots and major renovations, giving families, children, seniors, and all pedestrians a safer place to walk away from moving vehicles.

A simple design change could save lives. Please sign and share to help make parking lots safer for everyone.

For maximum impact on Change.org, I'd also include a link to your petition in every social post and keep the first sentence exactly as written—it immediately establishes why this matters to you personally.