Normal operating hours of the Pedway are 7am to 5pm, Monday - Friday, unless otherwise noted.
Does most of it follow that schedule? That seems like a very limited time. If you wanted to use it during your commute you'd be limited to work between 8am and 4pm.
Not sure if that was widespread but by 6pm the Loop proper was basically a ghost town.
Most common official working hours are 8-4, since there are so many banks and exchanges that want to be on the same work schedule as NYC markets.
Also it gets dark at 4:30 in December/Jan and millions of perestrians, cars, dark, and icy streets aren’t a very safe combo.