Answer: It may be easiest to wait until they bloom next spring, but in the meantime you could seek out some photos of multiflora foliage and hips if you want to try to identify them now. Here is the url for a photo of the foliage:
Here is the url for a photo of the hips.
Here is the url for a photo of the flowers.
Note however that some of the old fashioned shrub roses, and some of the roses used as root stocks for grafted roses, could possibly be confused with this plant.
Q&A Library Searching Tips