It's very difficult to find information about Korea as the most dangerous place for a pedestrian in the world. That's quite a bold statement, and I can guarantee I've felt less safe in other parts of Asia, especially toward the sub-continent/middle-east.
A quick search claims Isreal, North Korea, Peru, and numerous other places as 'the most dangerous places in the world for pedestrians.' North Korea was mentioned in one article. I've yet to find South Korea.
However, what I did find is these statistics for world cities.
According to this, America is beating all records:
Pedestrian Fatalities per 100,000 residents
1. Atlanta 10.97
2. Detroit 10.31
3. Los Angeles 7.64
4. Baltimore 7.54
5. Philadelphia 6.22
6. Chicago 5.89
7. Washington D.C. 5.74
8. Milwaukee 5.68
9. San Francisco 4.33
10. Boston 4.24
11. Seattle 4.12
12. Copenhagen 3.92
13. New York City 3.49
14. Portland 3.39
15. Amsterdam 3.36
16. Paris 3.09
17. London
18. Hong Kong 2.1
19. Tokyo 1.7
20. Berlin 1.6
I didn't know North Korea had more than a dozen cars.