It’s late at night on the interstate and you’re following what appears to be an impaired or fatigued driver in front of you. All of the telltale signs are there: failure to maintain a consistent position in a single travel lane, changes in velocity and what appears to be slower than normal reactions to traffic and roadway conditions. Being proactive, you conduct a traffic stop and discover that the driver isn’t drunk, but suffering from sleep deprivation.
What you can’t—or didn’t—see is that the entire time you were following this vehicle, the vehicle itself was doing whatever it could to alert and protect this sleepy driver, including making lane corrections on its own, sounding buzzers, applying brakes independently and even vibrating the steering wheel. The vehicle couldn’t pull itself over to the shoulder or the nearest off ramp, park and shut off on its own—at least not yet—but it was employing just a few of the proactive dynamic safety devices currently available in modern vehicles.
Active Safety Devices
Why is it important, you might ask, to know more about these devices? There are a few reasons, but let’s first define what active safety is.
Simply put, there are two types of safety: active and passive. Active safety is everything the car does to keep you out of a crash, while passive safety encompasses the items that protect you during an actual crash—e.g., airbags, seatbelts (you DO wear them every day, right?) crush zones and safety cages. Passive safety is certainly important, but if you consider that the “safest” vehicle is the one that doesn’t get into a crash in the first place, then the importance of active safety becomes elevated.
Now that we have defined the difference, let’s return to why it’s important you understand modern active safety devices. The first reason is that the patrol vehicle you drive every day likely has a good deal of them already installed, but if you aren’t aware of them, or haven’t been trained, you can be confused when they activate in real-world situations when you’re behind the wheel.
In the past, ABS (Anti-lock Braking System) was the only real active safety device on patrol vehicles, and training for that was still missing in some academy EVOC curriculums for many years. The addition of traction control, stability control, pre-charged braking systems and other active safety technologies that are in modern patrol vehicles right now still haven’t been addressed in standardized lesson plans. Companies like SkidCar offer classes that train officers on the capabilities and limitations of stability control systems (known as ESP, Stabilitrak, ESC and other proprietary monikers), but the vast number of agencies still don’t train on these systems. So, you need to educate yourself on them, and understand their functions.
A second reason is that the technology discussed in this article is coming to patrol vehicles—maybe not tomorrow, but someday. So, better to be ahead of the curve. A third reason is that understanding the role of these systems will become increasingly important when you’re evaluating driver behavior on the roadway and in crash investigations. As an example, a vehicle without an advanced stability control system will react differently than one with such technologies if both are exposed to identical dynamic situations. Furthermore, knowing which systems are on what vehicles can support or rebuke a civilian driver’s assertion that the cause of the crash was attributable to a dynamic behavior that would be highly unlikely given the presence of a given active safety technology on the vehicle in question. I could expand on these reasons significantly, but the bottom line is that active safety technologies are increasingly filling the confines of modern vehicles.
So let’s look at some of those technologies. Some may seem farfetched, but each of them is installed and operational in a vehicle somewhere in the world today.
Emerging Technologies
Lane Keeping Assist— Mercedes-Benz
Failure to maintain lane is one of the primary factors in collisions. In fact, according to Mercedes-Benz, it accounts for one in six roadway crashes in Germany. In response, the company developed Lane Keeping Assist, a feature for passenger cars that warns the driver or even takes corrective measures automatically via ESP (Electronic Stability Program) as soon the system detects that the vehicle has left its lane.
How does it work? A camera mounted in the windshield area films the lane in front of the vehicle and passes the data to an electronic control unit that detects the lane and markings using differences in contrast. At the same time, it determines the position of the vehicle itself. If the control unit detects that the vehicle has left the lane unintentionally, a vibration motor in the steering wheel warns the driver by subtly vibrating the wheel. The warning doesn’t activate if the driver accelerates before passing another vehicle or merges onto a freeway, brakes heavily or enters a corner.
Active Lane Keeping Assist serves a dual purpose: It can also detect oncoming traffic and occupied adjacent lanes and reduce the risk of the vehicle leaving its lane unintentionally by applying the brakes on one side. As soon as the system detects a driver input, it ends the automatic intervention.
XDS—Cross Differential System—Volkswagen
Understeer, which can be defined as the front wheels taking a larger path, or radius, through a corner than intended, is a common factor in crashes (e.g., too much speed into a corner, too much throttle exiting a corner, over-application of steering input, tire slip angle exceeding optimum). Volkswagen developed XDS to reduce under-steer during cornering, while also reducing the tendency of the inside front wheel to spin under acceleration during heavy throttle applications, a common issue with many front-wheel-drive (FWD) vehicles.
According to Volkswagen, the XDS electronic differential lock is an extension of the familiar EDL (Electronic Differential Lock) function. However, XDS responds not to loss of traction but to the unloading of the front wheel on the inside of the corner when cornering fast. XDS applies pressure from the ESP hydraulics to the inside wheel to prevent it from spinning. This improves traction and reduces the tendency to understeer as it also “slows” down the inside wheel, causing the nose of the car to want to rotate around that wheel.
Think of how a battle tank works. To turn, the metal track on the side of the intended direction is slowed, while the speed of the track on the other side remains the same. The difference in track speed causes the tank to turn toward the “slower” side. XDS works in a similar fashion, between the additional centripetal force created by additional inside wheel traction plus the difference in speed between the front two wheels. The sensation the driver feels is similar to that of a limited slip differential.
Smart Obstacle Avoidance Technology—Ford
In driver training, we teach employing visual scanning and finding an “out” when encountering an obstacle that presents a hazard. In other words, since we drive where we look, then looking around the obstacle to find a safer place to steer the vehicle is key.
Unfortunately, most drivers are not taught this, so they “stare” themselves right into the very obstacle they are trying to avoid. Ford recognizes this, and in response has developed Smart Obstacle Avoidance Technology. Although this technology is still in testing phase, it has been featured in a Ford Edge Concept, and it seems headed for mass adoption in future Ford products.
According to Ford, the system uses automatic steering and braking to avoid collisions with vehicles that are stopped or slowing in the same lane ahead. The system issues warnings first if it detects slow-moving objects or stationary obstacles ahead. If the driver fails to steer or brake following those warnings, the system will then automatically steer and brake to avoid a collision. Obstacle Avoidance uses three radars, ultrasonic sensors and a camera to scan the road as far as 656 feet ahead. If the system detects a slow-moving or stationary object, it first displays a warning, then sounds a chime. If the driver does not steer or brake, the technology applies the brakes, scans for gaps on either side of the hazard, and takes control of the electronic power steering to avoid a collision. Obstacle Avoidance has been tested at speeds greater than 38 mph and incorporates sensors and technology also used for parking assist.
Forward Collision Warning—Chrysler
Those of us who have investigated traffic crashes know that failure to reduce speed or inattention to driving frequently contribute to rear-end collisions. In response, Chrysler has developed Forward Collision Warning and Warning Plus, which use forward-facing radar sensors to detect when the vehicle may be approaching another vehicle too rapidly, and alert the driver accordingly. FCW-Plus adds to this: If the driver does not respond to the alerts, the vehicle’s brakes automatically pulse as an additional warning; if the driver still is unresponsive and a collision remains imminent, brakes are applied to slow the vehicle before impact.
Pedestrian and Cyclist Detection—Volvo
Collisions between vehicles and pedestrians or bicyclists are common issues on our roadways. Volvo, whose name is synonymous with safety, has developed a system that addresses both of these hazards. According to Volvo, the Pedestrian and Cyclist Detection with full auto brake detects and automatically brakes for cyclists swerving out in front of the Volvo, or a pedestrian that steps out into traffic.
The system is an enhancement to detection and auto brake technology present pre-2014, and is now featured in the entire model lineup. The advanced sensor system scans the area ahead using radar and a series of cameras, determining the shape and profile of approaching objects. It monitors the speed and trajectory of the object and if it determines it to be a pedestrian in danger, or if a cyclist heading in the same direction as the car suddenly swerves out in front of the car as it approaches from behind, it will prompt the driver to act with a flashing red warning light on the windshield, along with an audible alarm. If the driver doesn’t react to the warning and a collision is imminent, the car immediately brakes with full braking force sufficient to engage ABS. The system can’t guarantee a collision won’t occur, but it can go far in minimizing the impact speed and forces.
The BIG Caveat
Ok, so the technologies we just discussed are significant, relevant and, for the most part, are in 2014 model vehicles, and in some civilian models of modern patrol vehicles (Ford’s Curve Control on the Explorer, for example). These active technologies can go far in helping to reduce collisions, but until we reach a time where driving a vehicle is like hopping a subway—where we have no responsibility for the actions of the vehicle—these technologies should not be relied on to replace common-sense, aware driving behavior bolstered by regular training.
Take some time to thoroughly research the active safety systems on your patrol vehicle. If it has brake assist, learn what it is and find a way to get trained on it. If it has stability control, required on all vehicles produced since 2012, then make sure you enroll in training with companies like SkidCar to understand fully what the implications and dynamic behaviors of such systems can and cannot provide. The time to learn is not in the middle of a critical incident. As officers, we are held to a higher standard and, like the firearm we carry, we have the responsibility to understand the capabilities of our vehicles. Doing so might just save your, or someone else’s, life someday. LOM