Unfortunately, we need to be extremely careful anywhere we are walking outside. My husband was walking on the sidewalk and was hit by a car on Friday night. Yes, walking on the sidewalk. Luckily, the car was not going too fast, but fast enough my husband couldn't get out of the way (the car came up behind him - no warning honk or anything). He wasn't hurt - just a little sore. We've learned there isn't much you can do with these kind of things, so he didn't call the police or anything. (For example, we've tried calling 119 when a drunk old Korean man was trying to break into our apartment at 2:30 a.m. one morning and there was not English speakers, so we just had to wait it out.)
I live in Incheon and we have seen many cars driving on the sidewalk in my neighborhood. My only explanation is that there is some construction and driving on the sidewalk tends to be a little faster than driving on the regular roads...
I'm so sorry this happened to your friend. It is such a needless shame.