Definitely give yourself 45 minutes to an hour early just in case. The shuttle's are fairly quick. I only waited 10 minutes.
Worst facility in the country for rental cars. Far away, shuttle infrequent, gas not convenient.
The are always attendant's available and it doesn't take much time.
The shuttles run every 15 minute. However going through security check point in BWI is getting crazier. I will say 1hr to safe.
There 24 hours, 45 + minutes
Yes they are there 24 hrs a day. I would give myself 45 min to 1 hr to get to terminal as I dont know how often the shuttle runs at that time of day.
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