Heck, you may even feel like just staying in the left lane, but can you? When it comes to left lane etiquette in Massachusetts (whether you're driving on the Mass Pike or elsewhere), you can't stay in the left lane indefinitely. Here's what the actual law says about left-lane driving in Massachusetts per malegislature.gov. In other words, you can legally drive in the left lane when actively passing another vehicle or taking a left turn, but camping out in the left lane for no special reason, as accepted by Massachusetts law, is illegal. If you violate left-lane driving in Massachusetts, you can actually be fined $100.