Oops, I forgot to add my nominations:

First, any road in the Greater Boston area, again due to the seemingly deliberate ignorance of MUTCD (Federal) standards regarding signage, lane-widths, and lane-striping. Even the new Big Dig stuff is not in compliance. Plus Massachusetts allows driving in break-down lanes/shoulders on some roads! Too bad for you if you actually have a breakdown or want to exit safely.

I-95 betweem Philadelphia and Delaware. Badump-badump-badump.

The Pennsylvania Turnpike due to its narrowness of ROW (it was built to be a railroad, no?)

The Million Dollar Highway in southwestern Colorado, only because it has few if any guard-rails and narrow shoulders (which double as cliff-edges!). It is thrilling and beautiful, but difficult to defensively-drive.

I-15 between Cajon Pass (far eastern Los Angeles area) and the CA/NV line right now due to the widening project. Not fun to do those Jersey barrier chutes with people who want to go 90 mph!

The Pasadena Freeway, only because it still should not have the title "Freeway" when it has many 5 mph on/off ramps and is forbidden to trucks (including you Madame Weekend Ryder Renter!). Call it the Pasadena Parkway please.

The Lions' Gate Bridge in Vancouver, B.C. because of the transition on BC99-NB from 4 lanes to 3 by Stanley Park (which varies by time of day).

The Chicago "Skyway" (towards Gary), unless they have replaced it recently. The last time I used it I thought "They should be paying me a toll!"

While I agree that the Robert Moses roads are bad now, it is amazing that they got built, and I wonder how NYC would function today without them. They, along with L.A.'s freeways, are simply overused/overcapacity (and because of that perhaps not properly maintained), not necessarily of poor design.

Good topic!