Ravenna is easy to get to from the A14. Follow the signs for A14D from the A14 East. The A14D ends some kilometres before Ravenna, but the roads to the town are clearly signposted. Once in the town, head for the centre (Centro). The town streets vary (as in all Italian towns and cities) with the main routes being large and navigable, the back streets being small and unsuited to large vehicles. As there are a number of ways in, make sure you have a town map before getting to the town, although this is good advice for any Italian town.
Parking is easily attained, some free away from the old town centre, and typically 3 euro for 2.5 hours on the main street near the entry to the old town within 200 metres of the Basilica.
There is a train station in Ravenna; there are main lines to Bologna and Rimini.
You can take a bus from any nearby town, it costs only a couple of euros.
There is an airport in the town of Forli' about 20 km from Ravenna. It serves Ryanair. The more expensive airlines fly to Bologna, about 80 km from Ravenna.
Occasionally Ravenna pops up on Mediterranean cruise itineraries as the drop-off point for Bologna and San Marino. If your cruise includes this stop, be warned that cruise ships dock at Porto Corsini, about 15km away from Ravenna city center. Most cruise lines will offer a shuttle service to the city, sometimes for a fee. Note that there is nothing of any particular interest in Porto Corsini except a couple of long beaches frequented by locals, and buses are quite scarce. Unlike many ports, you don't tend to get many tour companies coming to offer tours of the area, so it may be wise to pre-book a shore excursion from your cruise line - these are normally tours to Bologna, San Marino and Ravenna itself.