Head’s up, Florida pedestrians. It just may save your life. A new study about the most dangerous American cities for those who get around by foot finds that the top four are in Florida.

The top 10 US offenders, via Smart Growth America:

1. Orlando, Fla.
2. Tampa, Fla.
3. Jacksonville, Fla.
4. Miami, Fla.
5. Memphis, Tenn.
6. Birmingham, Ala.
7. Houston, Texas
8. Atlanta, Ga.
9. Phoenix, Ariz.
10. Charlotte, NC

So why do cities in the South and Southwest fare so poorly?

At the Washington Post, Emily Badger observes that, generally speaking, these are car-dependent cities that grew up “in the age of the automobile.” When they were booming in the post-World War II years, urban planners didn’t give much thought to pedestrian safety.

Contrast that with some of the most-safe cities, including Boston (the safest at No. 50), New York (48), and Chicago (43), which were laid out before the car became king. The top five safest, in order, are Boston, Pittsburgh, Seattle and New York (tie), and San Francisco.

This week the advocacy group Smart Growth America released a report tallying America’s 47,025 pedestrian deaths over the decade from 2003 to 2012. The total number of such fatalities has been on the rise since 2009, reversing the recent pattern, and pedestrians are now involved in a rising share of all traffic deaths, as this graph from the report illustrates:

That second trend, shown in the green line above, partly reflects the fact that while walking can be dangerous, riding in a car has become historically less so. This graph from the National Highway Traffic Safety Administration, charts the decline of motor vehicle fatalities since the 1950s, the overwhelming majority of which have involved people riding inside cars:

1. So, why are we making clear safety advances for people riding in vehicles but not for pedestrians traveling along some of the same streets? In large part, we’ve been able to address the first problem with technology and laws — with airbags and mandatory seat belts and steeper penalties for drunken driving. Pedestrian fatalities, however, aren’t a problem of technology, or even of the law (although many advocates would like to see tougher charges for drivers who cause those deaths). Rather, pedestrian fatalities are a problem of design.

And that makes them much harder to address. That means instead of retrofitting our vehicles with better technology, we need to retrofit streets and neighborhoods in some fundamental ways. We need to put sidewalks where they don’t exist. We need to engineer roads that aren’t so easily traveled at 50 miles an hour. We need to design intersections that prioritize both people and cars. We need to build places as if we actually think people might want to walk there — something we’ve seldom done along major arterial roads and commercial strips.

This problem of design is apparent in Smart Growth America’s rankings of the metro areas with the highest pedestrian fatality rates.