The company I work for has a lot of drivers, and they want those drivers to be safe. To help with that, all drivers have to take a Control Clinic class where they learn to respond to emergency situations in a vehicle. Turns out anyone at my company can take this class, so I took advantage of this and took the course last week.
In spite of working for a car company these days, I’m not really a car person. I work for a car company so that people in general can pay less attention to their cars. My thought is that most drivers already don’t pay enough attention, so we might as well make the cars safe for that.
The Control Clinic was at a race track, taught by car-guys, and gave me a bit of a window into their world. It was awesome, and I understand now why people get into racing. The drop in your stomach as you accelerate down a hill, racing your prior time, is exhilarating. In the control clinic, I only felt this as a passenger, but it has me planning to race again soon.
It wasn’t just fun though. I learned a lot from the clinic.
Geometry and Control
Cars have a lot more agility than I realized. I ended up doing a lot of different exercises, all of which pushed my ability to drive the car with enough control. In each case, the limitation was me and not the vehicle. When I was able to see and react, the car did exactly what I asked of it. One exercise had us braking and swerving to avoid a kid-simulating cone. At 70mph, I was able to do this even when starting my swerve only 20ft from the cone.
The main limitation on controlling a vehicle is often the driver. This is especially true on public roads where drivers are often not well trained and not focused.
On a racing track, I was surprised by just how much of racing is the driver being able to predict the curves of the track. A lot of racing, at least at the low level I’m at, is just a geometry problem. How do you create the smoothest curve around the whole track?
For our training, they put out cones on the edges of the road. You look from cone to cone, as soon as you’re at one your eyes are looking at the next, or maybe the cone two or three down. The cones help you identify the optimal curve around the track as you drive it. Once you know where the car needs to go, the rest of racing is a control problem. How do you keep your car as close to that curve as you can?
The emphasis in the control clinic was the positive goal: you steer where you look. This is exactly what they told me 20 years ago in driver’s ed, back when they showed pictures of cars that crashed into the only tree in a field. The driver was looking at the thing they were scared of, and their hands pulled the wheel to match their gaze.
As I learned with the cones at the edge of the track, it’s best to look far away. You want to be looking to the next waypoint you want to hit instead of where your car is immediately going. This lets you visualize where the optimal curve of the track is. Following this optimal curve, two “turns” in the track could be a single long and shallow pull on the steering wheel.
The control part of racing is the part that encompasses the vehicle. What I was really surprised by was the Control Clinic’s emphasis on traction budgets. As they put it, you only have so much traction available to the vehicle. If you’re allocating all of that traction to steering, you have none left over for braking. If you have all of your traction allocated to braking, your vehicle will under steer.
This, by the way, is the purpose of anti-lock brakes. ABS systems aren’t primarily intended to help you stop sooner. They give you steering control while you’re stopping. You have to use that steering control to be sure that you don’t hit anything as you slow down. Highly skilled racers will threshold brake, where they brake just to the point that ABS would kick in, then hold it under the threshold. This minimizes stopping distance while maintaining steering.
The idea of a traction budget reminds me a lot of the concept of control authority in aviation. Control authority is a measure of how much impact control inputs (like steering, braking, or accelerating) have on the actual vehicle motion. When a car goes into a skid, you lose traction and thus control authority.
Observability
One surprising thing about driving fast is that you can get a really good sense for what a car “wants” to do. Where is the steering wheel pulling when you lose traction in your back wheels? What’s the feel of the brake pedal as you approach ABS? Where is the momentum of the car pointed during the turn?
The more you learn to understand what the car is telling you, the more you can control how the vehicle moves through space.
One training tool the clinic used was a car with what were essentially training wheels on each back wheel. Those training wheels barely touched the ground, but they reduced traction enough that you could make the car spin out very easily. This simulates driving on ice or snow. The first time you feel the car skidding out, it feels like there’s no possible way to maintain control. After experiencing it a few times, I learned how to listen to the vehicle. While fishtailing, you can feel where the car wants to go, or where it has steering authority. If you control when you hit the accelerator just right, you can drive out of surprisingly serious skids.
One of the keys to this was that I kept my eyes locked where I wanted to go. That, along with my sense for how the vehicle was moving, was enough to let me guide the car even when there was no traction in the rear wheels.
In some ways, driving under these circumstances is a good metaphor for life. Driving like this requires you to know what the vehicle is doing now, where you want to go, and have the ability to control the vehicle in between. This reminds me a lot of the Likke model of strategy: means, ends, and ways.
The human element
The instructor I had riding shotgun for the class was very snarky. He joked a lot about me and the other students, guessing at our skills. He wasn’t particularly mean about it, but he also wasn’t nice. At first I thought this was just his personality. The more the class went though, the more I realized he was trying to get us to take it less seriously. His snark about what we were doing focused us on the task, but it also made us laugh.
Being able to smile was surprisingly helpful. I noticed that I performed a lot better when I was relaxed but focused. I didn’t want to be taking it easy, but I did want to avoid psyching myself out.
In a similar vein, driving with other people near you on the track is very distracting. This is basically the same on the track as it is on a daily commute. Driving can be pretty fun when nobody else is around. As soon as others are driving near me, the inherent unpredictability adds a lot of stress.
In the course, we did a stopping exercise with two cars. An instructor drove one car, while I drove another immediately behind him. I was one lane over, but trying to maintain 1 to 2 car lengths between the cars. The goal of the exercise was that when the instructor in front slammed on his brakes, I could stop my car before going past his. In a highway scenario, failure would amount to rear ending a vehicle if it has to stop suddenly.
The instructors did a great job trying to be distracting, and successfully got me to glance at my speedometer during this exercise. That half-second switch of my eyes caused me to be late on braking, blowing past the forward car. What I realized doing this is that can only really pay attention to one and a half things on the road.
I drive on public roads because other people are highly predictable. I don’t actually need to pay attention to them much at all. But sometimes that’s not true, and having been paying attention to the right things can save your life.
In the long term, one of the reasons I’m hopeful about autonomous vehicles is that they are always paying attention. In the short term, I’m glad I have a few more tools in my driving tool belt after taking this class.