Other mistake: In the scene when Robert gets caught up in the trap by Grand Central Terminal, there are no traffic lights on the upper street that they show him being suspended from.
Other mistake: How did Anna drive from Maryland to New York, where Dr. Neville was, if all the bridges were blown out?
Answer: In the alternative ending Dr.Neville, Anna and Ethan are seen driving a car over a bridge that wasn't destroyed. The army would need to leave a entry/exit point, but it would have been heavily guarded until everyone died.