We call that Road Diet....yep, skinny them lanes and people slow down. Same is opposite when we add 8' shoulders to a 2 lane highway that is only 24' wide. Once we make it 40', the public response is faster speeds.it's always amazing to me how people react to stimulus like road lines. I do a lot with our town for alternative transportation and one thing we deal with a lot is how to slow down high speed traffic in neighborhoods and smaller roads (many of our older neighborhoods were build with through roads). Simply adding or narrowing road lines is a very good way to reduce speed in many cases (to a degree, anyway).