Alphabet Inc's (GOOG  ) (GOOGL  ) autonomous driving technology unit, Waymo, has been at the receiving end of increased skepticism after its rival Cruise's recent involvement in an accident. Waymo has been responding to criticisms and striving to set itself apart from its troubled rival.

What Happened: Waymo on Friday shared a piece by Arizona State University Professor Andrew Maynard highlighting that no two autonomous driving systems are created equal. The professor noted in the article that a recent study between Waymo and Swiss Re indicates their cars are safer than human drivers when operating fully autonomously. "I've been keeping an eye on Waymo for a while now, and must confess that I like the company," the professor wrote.

"Safety is our priority as we responsibly advance the Waymo Driver," Waymo said in another post, while adding that it performs 'rigorous review' of its technology and operations before taking any incremental step. It performs ongoing evaluation to improve Waymo driver and will soon assess its performance by comparing it with a human specialist in Arizona, the company added.

Why It Matters: Last week, several unions and labor groups including United Auto Workers (UAW) wrote to the U.S. Department of Transportation and the National Highway Traffic Safety Administration (NHTSA) pressing for open investigations into automated vehicle operators including Waymo, Zoox and Beep.

"Let us be clear: ADS-equipped vehicle operations are unsafe and untenable in their current form. This industry is in dire need of federal regulation and leadership to restore a modicum of safety and establish a realistic path for these vehicles to operate without threatening other road users - including those represented by these unions," the letter stated. Likewise, criticism has also been circulating on social media.

Autonomous vehicle operators have been at the receiving end of flak since a Cruise AV got involved in an accident in early October. In the incident, a human-driven vehicle traveling adjacent to a Cruise AV collided with a pedestrian, sending the pedestrian across the vehicle and onto the ground in the path of the AV. The AV made contact with a pedestrian and pulled them forward by about 20 feet. The General Motors Co's (GM  ) autonomous vehicle subsidiary issued a recall for a subsystem within 950 of its automated driving systems following the accident.