One of the fundamental ideas in taijutsu practice is to take it slowly and build the muscle memory, and only speed up later. However, there is an area where it's not practical to slow down as far as we do elsewhere: ukemi, or rolling and falling. At some point, when you roll, you have to do two things at once while moving. That is because your own inertia is part of the technique.
Still, you can break it down to elements, and practice that way. Also, some rolls are simpler than others.
We went out to the park today and rolled to our heart's content on the grass. Usually at this time of year, Fudou Myou migrates indoor. But the weather was great, the grass was dry (mostly).