You should be able to safely get through if there are no runners and you are patient with the volunteers that are helping with traffic. Go out at least an hour before you have to leave and explain to the volunteers - maybe they can help coordinate it for you with the police that will be available. Remember to have patience since the runners will not be stopped to let a vehicle thru. You also may need to leave earlier than originally planned or need to sit and wait at the intersection until there is a good break between runners both ways.