There is one trail/path west of Philadelphia that was originally “sold” and funded as a commuter route. It is paved and stays in excellent condition. As it was designated a commuter route they must plow the snow off. And they do. County Park service so not the folks who do the roads. But there are sections that rarely see the sun due to terrain and tree cover so I have to keep a sharp eye out for ice.
That trail is the only one I’m aware of. I mostly ride around the neighborhoods (10 to 15 miles) during the winter. And only between 9:00am and 3:00pm (no cars).