ありがとうございます。 質問の解釈はほとんど合っています。

Thank you very much. Your answer is almost perfect for my question, and I understood very well.
>DDRHW-4 requires a large interchange
わかりました、日本の都市高速のように小さなインターチェンジ(単純な合流分離)は作れないんですね。日本では比較的頻繁に見かけるスタイルなので、できると思っていましたが仕方ないですね。
Thanks and I understood, unfortunatelly DDRHW-4 cannot make smaller interchange such simple branch or combination.....
I thought it is possible because it's often used typical smaller interchange for "Urban Expressway" in Japan.
However I understood it's not possible now.
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"Urban Expressway" is a smaller highway. It is used as an intra-city highway for aviding traffic jam or fater trip.
We can find some "Urban Express" ways at downtown in big cities in Japan such Tokyo, Osaka, Fukuoka and so on.
They are often constructed double-decker styled highway (furthermore there is often a local street underneath!) due to lack of space.
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>DDRHW-4 is not stable and the lane directions reverse.
ありがとうございます、今後の改善に期待しますね。
Thanks,and I understood.
I'll wait and wish for improvement.
>Please, in the future. try to post in simpler language.
了解しました。
Noted with thanks.
I'm sorry for my bad English.