The day before Thanksgiving, Loudoun County elementary school principal Kathleen Hwang died. She was trying to cross a road in her Sterling neighborhood.

How should we react to such a tragedy? Certainly we should mourn the loss of a beloved member of the community. But can we also learn from this experience as part of an effort to stop it from happening again?

Instead, our natural reaction seems to be to try to figure out which individual was at fault. Was it Hwang? The 18-year-old driver of the SUV that hit her? Police often hew to the assumption that the pedestrian was responsible. In many crashes, there’s no easy way to determine if the driver was distracted, so that possibility is rarely, if ever, a part of police and news reports. But the reported fact that Hwang was wearing earbuds — which might or might not have played a role — gave some people an easy way to dismiss the issue and move on.

Everyone — drivers and pedestrians — should pay attention on the road. But we know that many of us don’t. Our roads shouldn’t exact such a high price for our inevitable moments of carelessness, especially when the pedestrian pays the higher price for the error either way.

In her Nov. 27 Metro column on the accident [“In Loudoun, treasuring memories of a principal”], Petula Dvorak extolled the schoolchildren who responded to Hwang’s death with simple grief and chastised all the “grown-ups” who instead “launched tirades” against earphones, SUVs or suburban culture.

Fortunately for all of us, however, these sorts of grown-ups were around to respond when injuries at factories or construction sites were commonplace or when people died in large numbers from lack of access to clean water. Throughout its history, the nation has continually examined preventable and common causes of death and worked to eliminate them.

But we have a very large blind spot. In 2008 and 2009, motor vehicle crashes were the leading cause of death for Americans ages 8 to 34, according to a National Highway Traffic Safety Administration analysis. We rightly demand explanations and corrective action after crashes of trains, boats and airplanes. Why not for cars, the most dangerous things in the lives of the children Hwang nurtured at her school?

Where does the blame rest? The sad fact is that we — our society as a whole — created this problem. That’s because we relentlessly build communities that aren’t safe to walk in.

In suburban Sheffield, England, in 2007, a report chronicled the lives of four generations in one family who all lived in the same area. When George was 8 in 1919, he was allowed to walk six miles to go fishing. His son Jack, 8 years old in 1950, could go to the woods a mile away. Vicky, 8 in 1979, was permitted to go only half a mile to a swimming pool, and Vicky’s son Ed, 8 in 2007, is restricted to his own block, about 300 yards.

Many of our suburban children face the same restrictions. Their parents aren’t necessarily being overprotective; they are responding to an environment that has grown increasingly dangerous. Not because of abductions, which are really vanishingly rare, but because from 1919 to today we designed communities around high-speed traffic, leaving no room for our children.

But we don’t have to choose between imprisoning our children and the ability to get to work and the store. All that is required is to demand that our leaders design communities that work for walking as well as driving. We must be clear that we consider one road death to be too many and that, while it’s not about blaming someone, the response to such fatalities must include a grown-up analysis of what is wrong with our road design.

Many communities have already learned ways to better design their roads. Intersections without signals (where crossing is legal but often dangerous) can get some full traffic lights or special pedestrian signals called “HAWKs.” Roads can include medians with spaces for people to wait while crossing. New developments can avoid unnecessary curves and provide connections in more of a grid-like pattern, which give drivers more ways to traverse an area instead of funneling all traffic onto a few dangerous super-roads.

Our engineers design roads and intersections based on the goals set out for them. For too long, vehicular “level of service” has been the sole consideration. Creating “complete streets” that serve all users must become the default for every project. The price of continuing on our current path is tragedies like Hwang’s and children without freedom, and that is a price too high.

But to make any progress, we also must be willing to blame ourselves. We killed Kathleen Hwang and 15-year-old Christina Morris-Ward, who died on her way to school in Germantown in October, and many more. To say “it was just an accident,” or facilely pin the blame on one person, is excusing ourselves from our responsibilities. We owe it to these children and adults to do better.

The writer is the editor of the blog Greater Greater Washington.