It depends on what time of the day you plan on traveling. The traffic in this area greatly impacts arrival time. I suggest you Google bwi to Rosslyn Holiday Inn when you arrive. It will show you exactly what modes of transp are availoable and how long it will take to get there via car, bus and or train, or uber.
Traffic should be busy. Line 201 bus 305 is $4 to $11 and takes 2hrs and 59 minutes. https://www.rome2rio.com/s/Baltimore-Airport-BWI/Holiday-Inn-Rosslyn-at-Key-Bridge-Arlington
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