The data and records group at SDOT has put together a map of pedestrian fatalities over the past five years (PDF).
Unsurprisingly, you can tell that pedestrian fatalities are more common where there are more people out walking. There are no statistics on pedestrian volumes throughout the city, so it’s hard to tell from this what intersections are the most dangerous.
3rd Ave has the highest concentration of bus stops of any avenue downtown and is the deadliest street downtown. 23rd Ave is one of the deadliest streets in the city and the Central District has an unfair share of fatalities among neighborhoods.