Self-driving truck startup TuSimple has added another $120 million to a Series D funding round led by Sina, operator of China’s biggest microblogging site Weibo, bringing the total haul to $215 million as it seeks to expand.

The company, which launched in 2015 and has operations in China, San Diego and Tucson, Ariz., hit unicorn status in February when it raised $95 million in the Series D round with a post-money valuation of $1.095 billion. This additional funding includes investment from UPS, which announced in August that it had taken a minority stake in TuSimple just months after the two companies began testing the use of autonomous trucks in Arizona.

TuSimple’s total funding is $298 million. New participants in the round include CDH Investments, Lavender Capital and Tier 1 supplier Mando Corporation.

The company plans to use the funds to continue developing its autonomous vehicle technology and expand its long-haul routes in Arizona and Texas.

TuSimple is working on a “full-stack solution,” an industry term that means developing and bringing together all of the technological pieces required for autonomous driving. TuSimple is developing a Level 4 system, a designation by the SAE that means the vehicle takes over all of the driving in certain conditions.

In late 2017, TuSimple raised $55 million with plans to use those funds to scale up testing to two full truck fleets in China and the U.S. By 2018, TuSimple started testing on public roads, beginning with a 120-mile highway stretch between Tucson and Phoenix in Arizona and another segment in Shanghai.

The company has more than 50 trucks and 18 contracted customers, according to TuSimple CFO Cheng Lu.

One of those customers is UPS, which initially tapped TuSimple to help it better understand how Level 4 autonomous trucking might function within its network. That relationship expanded in May when the companies began using self-driving tractor trailers to carry freight on a route between Tucson and Phoenix to test if service and efficiency in the UPS network can be improved. UPS and TuSimple conduct daily testing between Phoenix and Tucson.