Sensors: More, Not Less (Number & Usefulness)

The number of sensors on the average vehicle continues to rise, but it’s how you take that information and relay it to the driver that really matters.

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Which is more important: knowing how many sensors a modern luxury car has, or taking the information they provide and giving it to the driver in a way that is useful? In many ways, the answer to that question depends upon whether your paycheck comes from Purchasing or Engineering. If the former, you undoubtedly will be grasping your chest as you count off the eight ultrasonic sensors (four per bumper), three front-facing radars (two short range and one long range), camera (or a pair of cameras if you desire pedestrian detection) located next to the rain sensor behind the insider rearview mirror, another camera peering out the back to see what’s behind when reversing, twin short-range radar units in the rear for blind spot detection, tire pressure monitoring units (four) yaw rate sensors, rollover sensors, steering wheel rotation sensor, light sensor, front seat occupant sensors, capacitive sensors in the door handles (or a proximity sensor in the key fob), multiple climate control sensors (front, rear and side temperature sensors, a humidity sensor or two and heat load sensors), GPS . . . and the list goes on. This doesn’t even include the sensors being tested to check the health of the driver through galvanic skin response, heart rate, etc.

Look at this array of sensors from the engineering side, and you see a lot of information being gathered, weighed and disseminated around the car, including a good bit that combines the output of discrete sensors in order to expand safety system capabilities. Useful information all, but worthless without a proper alert system for the driver. “Right now we have two extremes,” says Tejas Desai, Continental North America’s Head of Interior Electronics Solutions. “We are either always yelling at the driver or doing nothing until it’s almost too late, and braking hard. We have to understand driver intent. I know from the car where he is going and what is happening around the vehicle — good or bad. But I have to know if he is paying attention, and where that attention is focused, to be able to bring him back into the loop.”

As you might have guessed, this means adding yet another sensor to the list enumerated above. That’s when Zachary Bolton, Project Engineer at Continental North America’s Algorithm Development group (, introduces the Driver Analyzer. A single camera with an LED light source to either side of the lens, it looks for facial curvature, a nose and a jaw line. From that information it can tell the orientation of the driver’s head, and estimate where he is looking. This is nothing new, technology like this has been around for more than a decade. However, the cost of the camera and light sources, as well as the software to keep track of an independent variable (a human head) in three dimensions within a confined space, has improved considerably in that time.

“When I add this information to what the safety systems are gathering, I get a much more complete picture of what’s happening,” says Bolton. This still doesn’t settle how to turn this information into something useful for the driver, however. What’s necessary is a man-machine interface that has several layers of alerts and responds accordingly. Ideally, it would draw the driver’s attention and focus it in the direction of the threat; the more dire the threat, the more intense the warning provided.

Continental’s “Halo” is not a sensor, it just reacts to what the sensors tell it. A 360° LED light strip that wraps around the interior of the vehicle within the driver’s and passengers’ line of sight, it can broadcast any color. This supports its second function as reconfigurable ambient lighting. Yet its main function is to move a notification through its discrete elements in the direction the driver needs to focus. “Depending on the threat level and how the OEM has set the alert hierarchy,” says Desai, “you can use this to get the driver to look where he should by, in essence, tapping him on the shoulder. From there you can engage the other warnings [alarms, vibrating seat, etc.] if the threat increases.”

It sounds so simple. However, the system also has to be forgiving enough that it doesn’t send out false warnings or continual alerts in non-threatening situations. “The last thing you want to do is desensitize the driver to the alert,” says Bolton. Therefore, the system looks at the driving style and situation, and suppresses the alert under certain conditions. Thus, a luxury SUV equipped with this safety suite and pulling a trailer may not alert the driver that he is hugging the right lane divider, if his eyes are forward and his path consistent. Similarly, backing up through tall grass toward a trailer won’t set off an alarm.

This system’s capabilities can be enhanced by using the front-facing radar to look under the car ahead to determine what is happening up the road, and provide an early warning. “If the traction is limited,” says Desai, “you could reduce acceleration while flashing a yellow band under the windshield. This would inform the driver that some-thing ahead is causing the car to react this way.” This adds prediction as well as reaction to a system designed to aid the driver in situations of overwork or inattentiveness, and increases its value to the buyer.

Though currently ported to a Cadillac XTS fitted with GM’s optional Enhanced Safety System, this technology soon will find its way into the mainstream. And with less expensive solutions (using the rearview camera to provide blind spot detection, replacing the front radars with lidar units and a camera, etc.), it’s only a matter of time before this technology becomes commonplace. It will be helped along by regulation, should Euro NCAP follow through on its idea of adding stars for collision avoidance systems while NHTSA proposes removing them for not having one. One thing is for certain, the number of sensors per vehicle will continue to rise, but the warnings they give will be more insightful.