Obviously, most accidents happen while the bike is in relatively high speed, which
1) makes it harder to respond to unexpected situations,
2) makes it harder to come to a stop,
3) worsens the impact (obviously)

If I maintain a reasonably medium or low speed on the city street, it will be less risky? (Of course there are occasions when faster means safer, such as when you are avoiding a car coming right at you: in that case beling slow would mean waiting to be hit )

I say "reasonably" because I don't mean to be so slow that I am blocking the traffic or becoming an odd ball on the street.