Also: Culturally speaking, Germans have (like the Dutch), always valued good product design. There's a nice cultural fit between IKEA (economical, good design) and the german market.
At least in NYC, they don't ban left turns, but the majority of streets are one-way; and they alternate street by street (or avenue by avenue). So you often need to put together 3 rights to make the left. There are exceptions (e.g., 42nd, 34th, and 23rd are all two way streets); but not too many.
In my city, many largest streets have left turns prohibited at all minor crossings - if you're "getting off the main road" and need to be on the opposite side, then three rights is the only way to get there.
Don't forget that if you're using animation and video to design a captcha, there are a lot of other design options possible: letters appearing one after the other, going in and out of blur, playing with colors, etc... A lot more graphical gimmicks can be added while maintaining comprehension for humans, and hopefully, improving blocking bots.
agree with rouxbe.com. their how-to videos/classes are very well put-together and the community of users incredibly active, insightful and participative.