Despite yet another recent accident where the driver placed the blame on Tesla's autopilot feature, car manufacturers aren't slowing down when it comes to getting semi-autonomous driving technology onto the roads. What they are doing, however, is pointing out the difference between fully autonomous systems and those that are only designed to aid drivers.

Nissan's new semi-autonomous driving system - ProPilot - is set to appear in the $28,758 Serena minivan, which goes on sale in Japan next month. While the company hasn't commented directly on the Tesla incidents, it specifically warned users not to overestimate what its feature is capable of.

"These functions are meant to support drivers, and are not meant as self-driving capabilities" which let drivers look away from the road, said Executive Vice President Hideyuki Sakamoto. "These are two very different things."

ProPilot is designed for single-lane use. Like Tesla's system, it requires drivers to keep their hands on the wheel even when in use. If the hands are removed, a warning sign will flash after four seconds and an alarm will sound after ten seconds.

The feature will automatically control the distance between the car and the vehicle in front, using speeds preset by the driver of between 18mph and 60mph. It can also keep the car in the center of a lane using its 360-degree camera system and on-board processors. ProPilot is meant to ease driver workload when highway traffic is heavy and on long commutes.

If the car in front comes to a complete stop, so will the Serena. It won't resume moving without direct input from the driver; tapping on the gas or pressing the ProPilot button will release the brakes.

While the ProPilot in current form is intended as a driver's aid, the company will be introducing more autonomy to the system over the coming years. The ability to handle multiple-lane switching is set to arrive in 2018, and it should be able to take on urban roads and intersections by 2020.

Nissan said it also plans to implement the ProPilot into the Qashqai sports utility vehicle crossover models in the next few months. The system is set to launch in Europe sometime during 2017, and it will arrive in the US and China at later date.