While the home games played in Baltimore's M&T Bank Stadium are always sold out, and a hot ticket, the Ravens are also are very popular road team, as evidenced by these graphs.
graphs courtesy of kind Redditor /u/hobbang
If you're confused about the meaning of the graphs, allow the creator of them to explain.
"I thought looking at how attendance numbers shift when a team visits could be an interesting way to visualize the popularity of each franchise. All of the attendance figures are calculated relative to the average usage of the stadium capacity of home team during a season. For example, the Chargers during the 2014 season have a 92.3% attendance of full stadium capacity, and I see how this percentage shifts with each visiting team."
The study is pretty comprehensive, spanning from '05-'14. Essentially, the graphs show which teams are the most popular, and which fans travel the best. The heart of the numbers focuses on how attendance increases when a team visits, so for example, if the Ravens visited Cleveland's FirstEnergy Stadium, you could expect attendance numbers to increase by around 0.5% from the mean attendance.
Baltimore placed 13th with division games included (0.5% increase), and placed the same with division games excluded (-0.1%). While at first glance the numbers seem surprising (and not in a good way), you have to consider that Baltimore is one of the smallest media markets in the league, with estimates ranging from 27th to 31st in market size. This map shows how Baltimore is outshadowed by Washington, D.C. and Philadelphia for media markets. Taking this into consideration, the Ravens ranking is even more impressive, and shows that the team's fanbase is suprisingly large and willing to travel to support their team.
While I've never seen a Ravens game live, I certainly plan to hit the road and skies to make my pilgrimage to Baltimore very soon. How many of you will be traveling to see your Ravens this season?