Article formerly published by CarDash. The ideas and opinions presented in this article are solely those of CarDash and do not reflect the ideas and opinions of RepairSmith.
Many newer cars have sophisticated safety and convenience technology on board, including adaptive cruise control, lane departure warning, and collision detection and mitigation. Although these features may be an intermediate phase as we move toward completely self-driving cars, they still have the potential for very significant standalone value.
CarDash to test some of these features, and began with the Forward Collision Warning system on a 2018 Jeep Cherokee. This is a similar system available on many Fiat Chrysler vehicles. Below is a video of our results, with further analysis below.
We first searched the internet for information on the FCW but couldn’t easily find answers to some basic questions, such as:
- How does the detection system work? Is it radar, LIDAR, visual, other, or some combination?
- Does the vehicle do any sort of intelligent analysis of the target in front of the vehicle, or is it just looking for any solid object? For example, can it distinguish between a car, a child, and very thick fog?
- What sorts of objects will the car brake for? One might expect it to stop for a traditional car, but what about a big rig who’s rear may be several feet off the ground? What about a dog that runs in front of the car? What about a cat? A squirrel? And how is it determined?
- Most importantly, how well does it brake? Will it stop before the object, or just slow you down?
These are all questions that are difficult for a FCA / Jeep owner to test on their Forward Collision Warning system because the system is only triggered when an accident appears inevitable else the owner would get far too many annoying false alarms. However, who wants to risk triggering an accident to test their safety system? FCA / Jeep owners are therefore always left wondering if their system is actually working.
It’s therefore nearly impossible to know if the system is working correctly. It would be like a new airplane not being able to test its ability to extend its wheels for a landing until it actually has to land. Not very safe, and not a good time to learn if your systems are working.
A recommendation for FCA / Jeep is to integrate a self-diagnostic feature. It would work like this:
- FCW diagnostic feature can only be engaged while the vehicle is in park and not moving.
- Once engaged, the system simulates a speedometer of a certain speeds, say, 10, 30, and 50 MPH, at the owner’s discretion via the regular dashboard controls.
- The FCW would be triggered based on the above simulated speeds. So for example if you were parked in your garage and engaged the FCW self-diagnostic at 10MPH, it would immediately brake (or simulate braking) because you are likely a few feet from your garage wall and simulating 10MPH movement. If you park 50 feet from a building, it should engage at the 50MPH speed, since you are simulating the movement toward an object at 50MPH that is only 50 feet away, and therefore an accident would be simulated as immediate (0.68 seconds to be precise). However, it may not engage at 10MPH (3.4 seconds away from an accident).
These self diagnostic tools would give analytically and safety oriented owners some peace of mind that the safety features they invested in are working as expected, versus the current complete unknown.
The results of our test
As shown in the video above, the results of our test showed that the Forward Collision Warning system does not perform consistently, and also is quite difficult to trigger. We tested everything in the range of 5–15 MPH, and the manual says the system should work at any speed.
The results were as follows:
- 12 drives toward a life sized vinyl poster of a rear of a vehicle led to 1 complete stop (no contact with the object) and 1 incomplete stop (the system began to brake but not in time to prevent an accident.
- We then added aluminum foil to the vinyl poster hoping that the metallic signature would help the sensors detect the object. On 9 drives, the FCW did not activate once.
- We then tried 3 times with a combination of the vinyl poster, aluminum foil, and a twin XL mattress. It attempted to brake 1 of the 3 times, slowing down but not preventing collision. 2 times it failed to trigger completely.