Why yes they are. You need more than just solar panels though. You'll need thick tempered glass, power inverters, monitoring and management systems, transformers and high voltage power lines. Once installed, your glass blocks will provide the ride comfort, noise, safety, of brick or cobblestone roads but less durable and more slippery.
I seem to remember that cobblestone roads were almost as slippery as ice whenever it rained. I grew up in a town that actually had cobblestone streets (long story, Europe).
