Hi.

Basically the source I added or modified highways was Amap, AKA Gaode Ditu
(https://ditu.amap.com/), one of the lagest online maps in China mainland, whose numbers of monthly activeusers were up to 800millions.
The region I mainly modified is a new Centrual Bussiness District of Guangzhou,China , where a great amount ofroads were constructed or upgraded in recent years.