Twice in the couple days I've had occasion to drive on Rt 128 southbound down below Rt 9, where four lanes become three and "breakdown lane traffic" becomes legal from 6:00-10:00am and 4:00-7:00pm. It's terrifying.
Most obviously, folks driving in the breakdown lane means you have nowhere to go if your car actually breaks down. With my '97 Subaru with a non-functioning gas gauge, the possibility is always at the back of my mind so I like to keep my escape routes open! Beyond that, the road simply isn't designed for high-speed travel in that lane. It's about two feet narrower than the actual travel lanes, and it has no white line on the right-hand side—nothing between you and the barrier. This is especially bad when exits and on-ramps are involved. You have to be a special kind of person to just drive right over the lines designed to corral you onto the road, at high speed.
And high speed is really the big issue. In stop-and-go traffic I can maybe understand the value of another lane, especially for folks who are exiting soon. But that's not what I've seen the last couple days. Instead, traffic has been moving fine and a few drivers are treating the breakdown lane like another fast lane. Nothing like getting passed on the right just as you're about to exit! Even worse is trying to merge onto the road: with cars moving along the far right of the road, the designed merge area is a danger zone. Instead of having time to check the traffic situation while driving straight, you're forced to merge immediately—like those terrible Rt 128 on-ramps up north in Peabody and Danvers but with four lanes instead of two and faster traffic.
I didn't enjoy it. I suppose if you do it every day you get used to it?