Couldnt agree more with Andrew..
the basics self-preserving reflexes you develop by being uke sink deeply in your system faster than the ones asociated with doing proper technique and since you're statiscally more susceptible to die falling from your bike than being attacked in the street , i would favor my ability to do safe ukemi over my developing of technique if i had to make the choice. (my background in aikido is 3+ years only , so it's gonna be a long time ukeing
Fall nine times , rise ten , they say...
It only matter that you stand again.