San Diego- and Beijing-headquartered autonomous trucking unicorn TuSimple said Tuesday it has raised USD 120 million in a Series D2 round, according to an announcement on its official site.

TuSimple is the world’s first autonomous driving startup with a focus on the trucking sector.

Investors in this round are US logistics giant UPS, Chinese private equity firm CDH Investments, and South Korean auto parts provider Mando Corporation. The new financing will bring its total funding to USD 298 million.

Funds from the Series D2 round will be used to ramp up its planned autonomous driving transportation service, in addition to strengthening the partnership with automakers and its top tier suppliers.

KrASIA reported last month UPS disclosed that its venture capital arm UPS Ventures has taken a minority stake in the company, without disclosing financial details. UPS is one of TuSimple’s 18 clients in the US. Additionally, TuSimple is also working with the United States Postal Service, for whom its self-driving trucks has been delivering mail since May.

The D2 round comes in the wake of TuSimple’s last financing round of USD 95 million in February, which the company then announced as “Series D”, backed by a group of investors including Sina, NVIDIA, ZP Capital, and Compound Capital. TuSimple claimed a valuation of USD 1 billion after that round.

The company didn’t disclose its current valuation, but did say in its website announcement published Tuesday that it’s raised a total of USD 215 million in the two D rounds.

The autonomous driving sector has been a white-hot sector in China and the US, attracting billions of capital injections.

Hong Kong-based startup AutoX, which was set up in Silicon Valley in the first place, closed its USD 100 million Series A financing round from investors including Alibaba, KrASIA reported on Monday.

Autonomous driving, which has a direct impact on human safety, also faces difficulties in witnessing real-world applications.

On the World Artificial Intelligence Conference held in August, TuSimple signed a deal with state-owned Shanghai Lingang Sci-tech City Economic Development Company Limited to commercialize its self-driving trucks on a large scale in the city.