I look at it this way.. In NYC I cover three airports. If I can make it to the closest (EWR) in 2-2.5 ish hours in normal traffic (which I define as NOT rush hour) and I have 1500-0000 SC, and they call me at 1510 to go to JFK, they just added significant mileage, but TWO bridges (Outerbridger or Goethals, and Verazzano) plus miles of Belt Parkway which can be a parking lot at that time. But I still could have made EWR in the alloted time with normal traffic. I get to JFK when I get to JFK.