Nissan’s ProPILOT Assist is a hands-on, driver assistance system. It is not an autopilot system. The technology basically incorporates two features – vehicle acceleration and braking assistance which Nissan calls Intelligent Cruise Control (ICC). ProPILOT Assist combines this with vehicle steering assistance. Nissan’s claim is that this system will reduce driver stress and fatigue in stop and go commute traffic and on long trips. I’ve been able to experience ProPILOT Assist for an extended period of time in both of these situations and have found that the system does pretty much what it says it does. Here are my observations.
Intelligent Cruise Control
Just like conventional cruise control, when the vehicle reaches your desired speed, the driver sets the target vehicle speed. Pressing the button with a blue icon on the steering wheel activates the system. Pressing the set button enters the desired speed. This activates the Intelligent Cruise Control, which will maintain the vehicle’s set speed. When approaching a vehicle moving slower than the vehicle set speed, a radar sensor in the grill detects the speed of the slower car, and will slow the vehicle speed to match that of the leading vehicle. When that car accelerates or moves out of the lane, Nissan’s ICC will accelerate back to the set speed.
I’ve experienced ICC on various Nissan products for quite some time now, and it works amazingly well. Many other manufacturers have a similar system, and it goes by many names, such as adaptive cruise control. Following distance can be set to long, medium, or short. This is done with the button with three lines on it. System activation defaults to the long following distance every time you turn it on. The following distance varies with the set speed of the vehicle. The faster the set speed, the more space is provided between the cars. This operates pretty much the way that you would normally allow some room between you and the car in front of you. You can tailor that following distance to your personal preference.
When driving in stop-and-go commute traffic, the system will adjust vehicle speed to maintain a safe distance to the car ahead. As freeway speeds vary, your vehicle speed will vary with the car in front of you. As commute congestion increases and speeds slow, your vehicle will pace the vehicle ahead. If traffic ultimately stops, you will come to a stop behind the car in front of you. When traffic starts moving again, a press of the resume button will reengage ICC.
If you’ve never experienced an advanced cruise control system like this, I recommend that you start with the long following distance to acclimate yourself to its behavior. Once you get more familiar with it, you may be comfortable in reducing the following distance, which can be useful in more congested driving situations.
Integrated steering assistance takes the system to the next level. Nissan positions a camera at the top center of the windshield, near the rear-view mirror. The camera is looking for the lane markers on each side of the lane that you’re driving in. If there are lane markers on only one side of the lane, the system will not work. Once it recognizes both sets of lane markers, your target path is the center of the lane.
Once you activate the set speed of the system, the camera will notify you when it acquires the lane markers. It does this with an audible tone and by changing the display on the instrument panel. You will see two green lines indicating the sides of your lane, and a green steering wheel just to the left of the lane marker indicators. Once the camera locates the lane markers, the steering wheel will also provide some resistance to your steering input. You still have steering control to override the system if needed, but there is a distinct firmness to the steering wheel response. You will also feel the steering wheel start to make minor adjustments, just as you would if you were steering the car. If the camera loses the lane markers, you will get a double chime and the green lane markers and steering wheel in the instrument cluster will turn gray. Also, the firmness of the steering wheel response is released, and the steering response will return to its typical light touch.
How does it work?
The system works fine. Nissan benchmarked it against similar systems offered by luxury brands. In several weeks of driving in pretty much every imaginable scenario that the system was designed for, it worked great. So, what driving situations is it designed for? Single lane control on a freeway or major highway. It cannot change lanes. In other words, you can’t use it around town or just say “Home, James” and expect to arrive at home in an hour or so.
Let’s start with the simplest scenario. Long distance freeway driving with minimal traffic. Once activated, the system easily maintains vehicle control and centers the vehicle in the lane. It works on concrete freeways with aged white lines which did not provide very good line visibility. It works extremely well on newer paved dark surfaces with freshly painted white lines. In a relatively challenging scenario, where the concrete freeway lanes do not coincide with the lane markers due to freeway expansion over time, the system easily tracked the lane markers rather than the contours of the actual concrete lanes.
One scenario that the system found challenging was a concrete freeway with only Botts dots as lane markers, and no painted white lines. While the system worked fine in good light, when passing through shadows (such as an overpass or trees), the camera would not always recognize the Botts dots. Interestingly, while writing this article I learned that Botts dots may be phased out due to this particular issue.
One other issue that I found was in construction zones. Where temporary K-rails or Jersey barriers were in use there were occasional issues. For instance, if there was no shoulder and the K-rail was adjacent to the lane. With one lane marker in shadow with the other in bright sunlight, sometimes the system could not detect both lane markers.
Finally, with the sun low in the horizon and in your eyes, it is also in the camera lens. In this instance, the system warned that it could not see the lane markers.
Possibly a more typical scenario would be commute traffic. Stop-and-go traffic while tired at the end of a long day is never fun. Once the desired speed is set, the system once again works great most of the time. It will try to maintain your set speed, but if traffic moves more slowly, your pace will be matched to the car ahead of you. This is where shortening the following distance is sometimes helpful. Other drivers often squeeze into the space left by the system (at least in Southern California) if left in the default long following distance. If traffic creeps along at two miles per hour, you creep along at two miles per hour. When the guy in front of you slows to a stop, you will stop roughly a car-length behind him. The system will hold you in place and when the car in front of you starts moving, just tap the accelerator or hit the resume button on the steering wheel and you will continue with your set speed unchanged. Sometimes at extremely slow speeds, it took the camera a little longer to find the lane markers.
When do you need to take control?
The system is designed to work with gentle curves and relatively flat roads. Driving down a 4,000 foot mountain pass with few straights and many bends, the system just said no. I think there is probably a certain level of torque that the system is capable of providing to turn the wheel, and if this threshold is exceeded it can’t keep you centered in your lane.
Another variable is freeway construction zones. If there is a lot of jogging back and forth and changing lane widths, the system did not excel, although it tried hard to maintain its lane centering function.
Finally, if driving in a large city, it’s best not to be in the far right-hand lane. Frequent on-ramps and off-ramps will have the system losing its way if they have no lane markings. Some states use dashed lines where the on-ramp enters or off-ramp exits, and in these situations the system should work fine.
What happens if you take your hands off the wheel?
If you take your hands off the wheel, you will get a visual warning on the instrument panel. If you don’t put your hands back on the wheel, the warning starts flashing and is accompanied by increasingly annoying audible alarms. The system is designed as an assistant for the driver, not a replacement. The system is looking for the resistance that you provide when holding onto the wheel. There is not a grip sensor built into the rim of the steering wheel.
ProPILOT Assist does exactly what Nissan says it will do – reduce stress and fatigue in commute traffic or on long drives. While the driver is still in control of the vehicle, and should be prepared to take full control at any time, it makes for much more relaxed driving experiences. Nissan has announced that ProPILOT Assist will be available on the 2018 Rogue and 2018 LEAF. You can likely look for it to make an appearance on future Nissan models as well.