i also got a blurred pattern... but i was thinking it would have been sharp in the pdf...
if it's not sharp there, i guess it should be a topic for a further ticket...
and for the pattern having a few exceptions: just put a whit rectangle and the pedestrian / bicycle right there :-)
anyway, i hope that it's possible to create a lighter pdf by using symbols... not sure it's possible, but if it is, scribus should do it!