I am sad to report that we never even tried the Roman bike share system. I got the best photos I could but most of the racks we saw were completely empty of bikes and we only saw one other couple riding them, once. I fear it's a bike share that failed.
It's all really too bad, because we discovered that in the city itself one bank of the Tiber is devoted to a bike lane, providing a high-speed safe beeline right through town. A cyclist could easily beat a taxi or subway rider on any cross-town adventure. Next time we're going to bring Bromptons.