I've had a bit of experience with Route 9 in Framingham. You have this one light near a Whole Foods which causes a massive backup, it can go for miles. The reason? There's another street that comes in at around a 30-40 degree angle to route 9, and it gets its own light cycle rather than having an on-ramp.

Big problem in RI, if you've ever driven down to the south county beaches on Rt 1, you'll actually be on a "highway" that has 6-7 lights. Why not just have off/on-ramps? Infrastructure is hard, apparently no one wants to spend on that.