I always back in when I park -- it's much easier to pull past my
driveway, make sure the driveway is clear, then back into it, than it
is to make sure the street is clear before I start, and remains clear
while I back out onto the street.

The driveway is a much more confined space, there's no other vehicle
traffic coming onto it, much less pedestrian traffic, and no room for
bicycles or skateboards to be going fast. The street has
intersections, other driveways, public sidewalks, bicycles riding on
the wrong side of the road, etc. And a motorist entering the roadway
is required to yield to all the traffic already on the roadway, so
almost any accident backing out of a driveway is going to be the
backing motorist's fault.

If I remember correctly, around 20% of all car/pedestrian accidents
are children being hit by cars backing out of driveways.

--
is Joshua Putnam
<http://www.phred.org/~josh/>
Updated Bicycle Touring Books List:
<http://www.phred.org/~josh/bike/tourbooks.html>