Five-year-old Harris Nyumah of Brooklyn Center was killed last Thursday by a garbage truck after chasing a ball into the street. There's little doubt it was an accident. There's no doubt his family's grief looms monstrously large, as does the grief of Mai Yer Moua's family. In April, the 3-year-old girl rushed across a street in St. Paul to follow her father. She was hit by a truck.

I'm a huge proponent of fighting against our primal fears for our children and pushing them outside to play, particularly in Minnesota, where summer is equal parts beautiful and brief. But my unscientific polling of young parents, in light of these recent tragedies, compels me to pass along information I didn't know myself when my kids were that age:

Children, literally, do not see the world the way grown-ups do.

Their vision, especially peripheral vision, is not fully formed until they're into their early teens. That means they simply may not see an approaching car out of the corner of their eyes. Even if they do see it, they are poor at making the connection between that car and what their next move should be.

"They may not necessarily know that a car is coming fast and they need to get out of the way," said Chrissy Cianflone, spokeswoman for Safe Kids USA in Washington, D.C. "They don't appreciate the risk, because they can't understand it yet."

More than 600 children die in pedestrian accidents annually, which may seem like a small number. But Cianflone notes that an additional 38,500 children are injured, suffering everything from bumps and bruises to traumatic brain injuries. Almost two-thirds of them are boys, "who are more likely to take risks. They dash out into traffic or don't cross at crosswalks or lights."

More than 80 percent of childhood deaths occur at non-intersection locations, such as near a school zone or their own home.

"Part of the issue is that parents often overestimate their child's intelligence and abilities," Cianflone said. "They'll say, 'My child won't dash out in front of a car, because I've told her no.' You can say, 'Don't cross the street,' but their instincts are what will drive them."

'All they want to do is play'

Dr. Seth Silbert, a pediatric ophthalmologist with Hennepin County Medical Center, appreciates what a difficult issue this is for even the most vigilant parents. "The visual system is a very complicated pathway. It's not surprising that we're not ready to use it in an adult manner until much later."

Still, what parent can watch a child every second? To this day, Silbert said he owes his life to a "very alert driver" who stopped on a dime as the then-7-year-old Silbert dashed into the street. Now he's a dad to a 3-year-old daughter who loves to explore.

"A kid is not going to recognize a threat at a young age," he said. "All they want to do is play."

And we should help them to do just that, with maybe a bit more vigilance than we assumed was necessary.

Silbert and Cianflone offer some good hands-on ideas. Never allow a child under age 10 to cross the street alone. Then teach them how to cross safely using traffic signals and crosswalks only. Show them how to make eye contact with the driver by lifting up their hand.

With younger children, hold their hands, especially in parking lots. Always walk around your car before backing out.

Silbert also would like to see neighborhood speed limits reduced to 15 or 20 miles per hour. "There is so much that has to go into the brain before the right decisions are made," he said. The biggest challenge as a parent is also the toughest, he added: "being able to anticipate something before it happens."

Cianflone agrees.

"If you know your child has that adventurous tendency, don't trust that 'I've taught them this.' It's not going to work because of the curious nature of a child."

Gail Rosenblum • 612-673-7350 • gail.rosenblum@startribune.com