How do you escape a marathon?

Not, as you might think, the first half of a hilarious new joke, but a real-life problem. This weekend was the Baltimore marathon and half-marathon and unfortunately we live (the photo is runners going down our street) and also rented a car inside the course! It took us an hour and a half to find a street where the po-lice were letting people cross when there were gaps.
Incidentally the house over the road from the car rental place is the house where the american flag that inspired the national anthem was sewn by Mary Pickersgill during the 1812 war. If you're extremely observant, you'll see that the flag only has 15 stars on it - an old-style version of the flag as it was then (each star representing a state) which is flown at historical sites round Baltimore.