How fast HV without battery capacity decline

Here in Marin County there are a lot of short ups and down on the north-south freeway through the county. Most are a couple hundred foot gain and loss. The grade leading south to the Golden Gate Bridge is about a 500 foot gain and 350 foot loss.

The ascents should be done on ICE. I wonder whether the descents will regen any significant amount back into the battery pack, and if so, how much more EV range they might provide for local driving.