Regarding the horrible collision involving bicyclist Matt Burke, it brings to mind the issue of speeding in general.
I have lived and driven on both sides and throughout the country in both large cities and rural areas. Never before have I seen such a high incidence of speeding in residential and other areas marked with a speed limit.
There is simply no good reason to be traveling at a speed of 50 mph in a posted 35 mph zone. It's illegal. This is why.