The directional antennas work great when you take the time to aim them where you think there may be a wireless signal.
In order for these to work optimally you have to stop, aim and then use them. They aren't like other antennas which are omni directional and will search in all directions for a wireless signal.
If you search around you'll find pictures of people war-"driving."
these pictures are generally of people in vans, stopped in neighborhoods, not exactly driving around