Amid tests of vehicles in Pittsburgh, questions are being raised about the safety of Waymo's autonomous vehicle technology after school bus violations. 

Videos from around the country show Waymo's self-driving cars not stopping for school buses or stopping too late. Right now, the ride-hailing service is testing vehicles in Pittsburgh. The first phase of that is someone driving the cars around. 

However, there are a few more phases before it goes all by itself. According to PennDOT, certifications and safety plans are submitted for companies like Waymo.

"We spent a lot of time, a good bit over a year, developing some guidelines for things they have to make sure they can do and prove to us that they can do," PennDOT Transformational Technology Section Chief Derrick Herrmann said.

With the school bus problems, Waymo says safety is its top priority, and no injuries have happened. It added that a software issue contributed to the incidents. The company, a subsidiary of Alphabet Inc., Google's parent company, believes an update should address this, but it is continuing to investigate.

PennDOT is watching how the National Highway Traffic Safety Administration investigation goes. Artificial intelligence advocates argue that they are still safer than human drivers.

"They're never distracted. They have to be right all the time. They always have to follow the rules of the road, and they have better vision. They have 360-degree vision," AI Strike Team CEO Joanna Doven.

PennDOT said there are seven other companies in the state right now using autonomous cars. Waymo stressed its safety record to calm any fears of self-driving cars.

"As we get closer to that commercial operation and whenever they launch that in Philadelphia, it's going to be a really good lesson for us, but I think we've done a ton of prep to try to be ready for this," Herrmann said.

Right now, there is no timeline on when the cars will go full autonomous in the Pittsburgh region.