Betcha it was winterberry. I think they are more likely to be heavy fruiters than the viburnum which often need a particular pollinator at exactly the right time.

I thought winterberry would be large?
Unless they were younger plants...

Could've been Burning Bush (Euonymus alata). Once the leaves drop, small bright red berries remain. It is considered invasive in some areas, including the Mid-Atlantic area (and pops up on the side of the road):

Viburnums are very good berry producing shrubs. The birds especially appreciate the native ones. I had a group of robins feasting on my Viburnum acerifolium berries yesterday.

it was very likely a viburnum, deciduous ilex (winterberry holly or winter red holly), euonymous (the invasive alata or the native american) or possibly a barberry that you saw on the side of the road - I hope it wasn't an old bittersweet - please don't consider planting that...