My street has a 7.5t limit but it's in a confusing place and is easy for drivers who have never been in the area to misjudge and by the time the see the sign it's too late. However it's not really a problem for us as the last place they want to end up is down my street as its a dead end so they end up having to reverse the distance. If the sign was 100yds earlier it would never happen.