The exact definition of an autonomous, or self driving, car varies considerably depending on the context. But self-driving cars can be best described as a vehicle that is able to sense aspects of its environment and respond to it without direct human intervention. This can range from automated parallel parking to journeying between two points with no driver intervention.

The following brands have been moving this technology forward at an impressive pace:

1. Tesla

Tesla is the first company most people think of when the subject of autonomous vehicles comes up. The company’s autopilot is getting steady upgrades over time and it’s sure to keep improving. One point where they differ from the competition is user monitoring. More and more companies are using facial recognition. However, the people who really started the trend are sticking with steering wheel monitoring rather than facial recognition to assess a driver’s focus.

2. Waymo

It’s hard to get more high-tech than google. The company has pioneered many aspects of modern AI. And Waymo’s autonomous vehicles use a considerable amount of technology originally developed through Google. The company is also notable for pioneering aspects of environmental adaptation. So people who live in areas with unpredictable weather might want to give this brand some special attention.

3. Pony.ai

This Chinese startup is getting a lot of attention in the West. They’ve recently received permission to begin testing of fully driverless vehicles in California. The company has already neared the point of offering a fully driverless experience through their robotaxi services. However, a human would always remain behind the wheel to ensure safety and compliance with local laws. What’s more, the company is also receiving some heavy backing from Toyota. A $400 million investment is sure to make a big impact as the company moves forward with its research and implementation. All of this paints a clear picture of a company that’s right on the verge of some major breakthroughs.

4. Volvo

Most people think of this company as one of the solid pillars of the industry. But they’ve taken on the role of pioneer far more often than one might think. They’ve been particularly noteworthy for research that’s helped promote vehicular safety. With that background, it’s little wonder that they’ve been working on self-driving cars. Their current major effort is the Pilot Assist II. It’s still lagging a bit behind most of the other major players. But given the company’s background and resources, it’s still well worth keeping an eye on them.

5. Voyage

Voyage is something of an outlier among self driving car companies. They entered into the business specifically with the hope of improving the lives of seniors. Many people aren’t aware of just how much a toll the aging process can take on people. Even seniors in relatively good health often experience impaired reaction times. It’s quite common for sensory issues such as impaired eyesight or hearing to make driving even more difficult. This company seeks to find ways to use self-driving cars to lessen the impact that age has on people’s quality of life. It’s an impressive goal, but the company is already seeing real world results. They’ve been working with retirement communities to help seniors live with full mobility even in their golden years.