What we do know: neighbors and local officials say drivers routinely blow through the four-way stop at that intersection. Police traffic enforcement in the area is reportedly down a staggering 90 percent. Let that sink in. Ninety percent.

So what's the city's response? SFMTA says it plans to install "playground warning" signs and implement "daylighting" — removing parking spaces near corners to improve sightlines — sometime this month.

Signs. After a toddler in a stroller gets hit by a truck. Signs.

Look, daylighting is actually a reasonable, evidence-based intervention. We'll give credit where it's due. But the broader pattern here is maddening. San Francisco spends enormous sums on its Vision Zero program — the city's pledge to eliminate traffic deaths — and yet when it comes to the basics, like actually enforcing traffic laws at dangerous intersections, we're operating at 10% capacity. You can redesign every intersection in the city, but if nobody's enforcing the rules of the road, people will keep running stop signs. That's not a design problem. That's a governance problem.

Workers at a nearby preschool aren't waiting around for the bureaucracy to catch up. They've launched a petition demanding raised crosswalks and flashing lights at the intersection — actual infrastructure changes that might slow vehicles down before they reach the crosswalk. A fundraiser has also been started for the injured nanny, because of course the community has to pick up the pieces when the city fails to do its one job: keep people safe.

Here's the uncomfortable math: we have a massive city budget, a well-funded transportation agency, and a police department that's apparently too understaffed or unmotivated to patrol a known problem intersection near a preschool. A child nearly died. The very least the city can do is move beyond signage and start treating traffic enforcement like the public safety issue it actually is.

More signs won't stop a truck. Accountability might.