Mercedes-Benz parent Daimler is investing in a Chinese self-driving startup, in another instance of a Western auto maker seeking out a Chinese partner to get a foothold in a challenging market. The German automotive giant made its first ever investment in a Chinese startup this week, taking part in a $46 million funding round for Momenta, a Beijing-based firm providing road sensors and high definition mapping software. It joins peers such as Hyundai Motors in aligning with Chinese firms as the race to develop an autonomous vehicle revs up. Western auto makers face high hurdles entering China because the country considers the kind of mapping needed to make self-driving cars work a national security issue and limits it to domestic companies. Foreign software and car companies also could face difficulty gaining approval to conduct test drives in the country, The Wall Street Journal recently reported.