Originally Posted by
threeoh
Yes but an airside connection would still be nice. No need for ATS, a tunnel from the tip L to the tip of M would only be 1000 feet long (300 steps).
Compare, for example, the tunnel from B to C is 800 feet.
I wonder what the total budget of the TTB (buses, labor, constructing accessible entrances) and the various airline-operated buses that predated it were compared to the one-time cost of the tunnel construction.
An airside tunnel can't replace the ATS for a couple reasons: You can't practically do security screening at T5 for all INTL arrivals making connections (not to mention walking to T1 is way too far) and without the ATS, you can't rent a car at O'Hare.