One factor to consider which goes hand in hand with it is traction. Modern brake systems such as V and disc can easily overcome the tractive ability of the tires used on a rainy or off-ideal scenario. A large number of my few roadie crashes were related to front brake exceeding the traction(on a 1974 Schwinn with chrome rims and good pads), and a little bit of wet on crosswalk lines. Not the fault of the machine, but still a braking/friction/traction fail.
As was sort of alluded to earlier by another reply, my dad always said when he taught us how to drive; "Never go faster than you want to hit or dodge around something."