I believe you might be trying to apply logic to the dates assuming there's only one or two variables changing across all those decades. The truth is there are multiple strongly correlated reasons pedestrian deaths declined sharply in the US over the years.

In the 1980's and 90's it was largely the safety standards being improved in vehicles. ABS being standard helped with stopping before hitting people. Road safety standards and road designs improved to allow for more pedestrian walkways away from the streets. Automatic headlights at night turning on, better road conditions, better tires were introduced to handle different weather patterns more easily (e.g. in the rain or snow where traction loss could lead to pedestrian deaths) as well as standards to increase vehicle inspections and what safety standards were being checked during those inspections.

In the 2000's, while many safety standards were still being improved and tweaked, a lot of the impactful ones had already been instituted, so the changes were less and less dramatic over the last 20ish years.

The specific question the OP was asking for was around the 2010 drop, and that is strongly correlated with high gas prices leading to sell-offs of SUVs, and SUVs are the leading cause of pedestrian deaths by far with modern cars with modern safety standards. Largely for the reasons others in this post have mentioned (larger, heavier, hood height, etc.).

I was very much a car nut during those years, and the gas prices drove many, many people to trade in their SUVs, trucks, etc. that had poor gas mileage. Gas prices were nuts, and a huge shock to everyone's budget when it jumped up suddenly. This wasn't really an inflationary thing, this was caused by a multitude of factors, but it stayed high for a long time due to those conditions.

When those conditions reverted, gas prices started falling like a rock, and everyone went back to thinking: "well, maybe I can afford that SUV again". And they did. SUV sales rose sharply once gas prices fell. So pedestrian deaths have gone back up as a result.

Today, it's also multiple factors, with the vehicle type being one of the large ones (hood height has been linked as a giant increase in the liklihood a pedestrian dies in a collision), but the other factor that rose sharply was smartphone use while driving from about the mid 2010's to today. It's probably the leading cause of vehicular deaths in general (I haven't checked, but I'd throw $20 at it being distracted drivers).

We children of the 80s were out there in them streets, walking and biking to our friends' houses and dodging the cars. Over the years our skills grew, and the numbers were finally on our side. And while it was sad on the rare occasion that we lost a friend to the streets as if they were an Oregon Trail character, it did help the numbers even more!