I am trying to find out the length of each of the tunnels driving from Rome to Florence...haven’t found a map source that clearly identifies that information...thank you for your assistance...
There are very few tunnels in that segment, not even 5, and each one of them very short, you’ll be underground just seconds. The longest is certainly the one before reaching Firenze Sud exit, under the village of San Donato (I think it’s called San Donato Tunnel). Even that one is definitely no longer than a kilometer.
For what it's worth, my TomTom European Navi allows me to specify no tunnels for my route. Comes in handy with my convertible.
Greatly depends by the road you want to drive on. If you use the highway there are some short tunnels, as Roberto says. But you can choose smaller roads whom pass over the mountains, that often are even much more scenic; of course are even slower.
BTW: If you use Google map, when you zoom in the road or highway became grey when is underground. Try to look for "Firenze Impruneta" and zoom in: when you are close you can see that some roads are underground. Another way is use the "satellite layer" in Google Map: when the road disappear means it's underground, so is a tunnel.
While it's probably not your main concern, Italy is a world leader in tunnel engineering with companies working and advising on projects world wide. Also Italian and European tunnel safety design and maintenance standards are top notch and patently better than most countries.
But you can choose smaller roads whom pass over the mountains, that
often are even much more scenic; of course are even slower.
Which is the way to drive between Rome and Florence in my opinion! If you just want to get there are fast as possible, the train is a better option.
However, the railway has several 5-mile long tunnels. They do not take much longer than 2 minutes to cross, but still.