I hadn't realized the practice had finally been codified. A motorcycle using the shoulder when traffic is stopped is illegal. Or at least it was when my friend tried it and got busted a couple of years ago. It remains expressly legal only in California, with an apparently slightly different allowance (called 'filtering' this time) being signed into law in Utah. If this source is to be believed, its in the process of being legalized in a half-dozen other states.actually, it’s expressly legal for motorcycles in CA since 2017 or sometime shortly after the passage of AB 51.
When addressing lane splitting and whether lane splitting is legal or illegal, you need to understand the parameters of the maneuver.