When Kramer brings home the highway signs, he shows Jerry how the kids changed the Speed sign from 65 to 165. The actual speed limit on the Henry Hudson is 50. That parkway also has 3 lanes instead of 4 (which Kramer reduces to 2). As an agressive driving New Yorker, I can assure you that NY drivers would never sit in traffic in 2 wide lanes!
The highway that Kramer adopts is actually the Henry Burkhardt - not the Henry Hudson.