They increased the width of roads because all vehicles sizes were increased as well.
Once upon a time, vehicles were pretty much all 4-studs wide. Now trucks are 6-stud by default but some are also 8-stud (and more to come in summer 2009), while even some car is now 6-stud.
And construction vehicles are even larger: 12-stud the XXL mobile crane (reduced to 8-stud the new version in the 2009 construction works center), 10-stud the 2009 roller, 20-stud the 2009 bulldozer!
The world economy is in recession, but in Legoland inflation is rampant