Personal opinion, you were going too fast for the situation and are lucky to not be injured/dead right now.
As a rule of thumb, I work on a difference in speed principle, in that I don't go 30kph (roughly 18mph) faster than any lane of traffic next to me.
Our reactions as human beings are only that quick, and the rules of physics is absolute, so give yourself enough time to react and you will be okay.
On top of that, smacking something at 30kph (the difference in speed) is likely not as serious as doing it at 60kph.
Cagers do the unexpected, so please slow down, give yourself time to judge each cager and time react before you pass them.