Disheveled, with bloodshot eyes, I banged on my keyboard frantically into the night in an effort to solve America’s most pressing mystery: What the hell is that Chevrolet Sonic with four-wheel steering that a Milwaukee reader emailed to our tips line?
“Tips – Rear Wheel Steering Seen on a Chevy Sonic” reads the ominous email’s subject line. The email describes a vehicle so mysterious few even know it exists:
I work next to a stadium that occasionally rents out their parking lot for driver training. Today, for the first time, I noticed a Chevy Sonic (I think) that was turning surprisingly quickly. After watching it do another lap, I saw that it had rear wheel steering. I’m assuming that the instructor was controlling the rear steering, and the driver had to react and correct the “slide”. The company is called Driving Dynamics.
Included in the email was a video of the mysterious Sasquatch strutting its stuff in the Milwaukee Brewers’ parking lot. Behold perhaps the internet’s only footage of a four-wheel-steering Chevrolet Sonic:
Just look at that thing swing its arse around that parking lot, cutting in tight between cones in a slalom, making even my BMW i3’s turning radius look like that of a giant oil tanker. Amazing.
But mysterious.
So I did a bit of digging, and what I learned is that this thing has an official name: The Controlled Slide Car. Here’s a bit about the company behind it, Driving Dynamics, which has been sliding in a controlled fashion for many years:
Driving Dynamics is North America’s preferred partner in the field of advanced performance driver safety training and fleet risk management. Its unique and highly effective approach to behind-the-wheel driver education, web-based learning and driver risk management has helped numerous fleet-based organizations achieve significant reductions in their crash rates. Founded in 1987 and headquartered in Newark, Delaware, Driving Dynamics has exclusive rights in North America to use its Controlled Slide Car (US Patent 5823288) at training programs conducted in 55 major markets at more than 200 training sites.
Basically, this is a driving safety company that specializes in making sure fleet drivers know what they’re doing. Driving Dynamics even has a “Driver Safety Excellence Hierarchy,” which is nice and corporate-y:
Anyway, let’s look at the patent for this Controlled Slide Car, since our tipster, Sam, has been agonizing over that four-wheel-steering Chevy Sonic for far too long and deserves to know. The patent was published in 1998, which is when Driving Dynamics says it introduced the Controlled Slide Car, so clearly there was a Chevy Sonic predecessor. By the looks of it, that original car may have been a Dodge Neon:
But how does this thing actually work? Well, the short of it is that the Controlled Slide Car is mimicking oversteer and understeer conditions, which are caused by “the interrelationship between the front end, rear end, and the center of gravity of the vehicle,” per the patent, which breaks the whole system, writing:
Specifically, the controllable slide car of the present invention comprises a rear steering linkage assembly and a controller that attaches to the rear wheel mounting assemblies of an automobile. In effect, the invention selectively “steers” the rear wheels to produce “sliding” of the automobile. Through operator manipulation of a control unit, the controller facilitates steering of the rear steering linkage assembly.More specifically, the controller is powered by the battery of the automobile via a control unit. The control unit contains an operator interface such as a joystick through which the operator “steers” the rear wheels of the automobile. As such, oversteer and understeer conditions can be simulated in a moving automobile when the joystick is moved in a particular direction. For example, when the joystick is moved in the same direction as the turning front wheels (i.e., joystick moved to the left during a left-hand turn), the automobile simulates an understeer condition. Likewise, when the joystick is moved in the opposite direction with respect to the turned front wheels, the automobile simulates an oversteer condition. When the joystick remains in a middle position, i.e., neutral position, the controller remains in a neutral position that produces a straight rear tire alignment.As a result of using the invention installed on an automobile, the automobile can be safely, accurately and controllably placed in an oversteer and understeer condition at any speed.
So basically, it’s a joystick operated rear steering system, and it’s presumably understeering the driver by turning the wheels in the same direction and oversteering the driver by turning the wheels in the opposite direction. How the driver reacts is meant to provide an indication of their emergency maneuvering/crash avoidance skills. If you’re a big company with lots of drivers carrying precious merch and lots of personal injury attorneys foaming at the mount to rob you blind, such training could be useful.
At least what’s shown in the patent looks rather primitive, mechanically, employing some tie rods and an electrically controlled ram (240 in the photo below):
Specifically, the rear steering linkage assembly 120 is affixed to the frame or unibody 250 of the automobile 102 at bracket 252, to the shock absorbers 104 and 105 and to the wheel mounting assemblies 108. Specifically, the assembly attaches to the backing plates 202 and 204 of the wheel mounting assemblies 108. The rear steering linkage assembly 120 contains a tie rod 206, control arms 212 and 218, and torsion bars 224 and 230. The controller 140 contains an electrical ram subsystem 240 and a control unit (144 in FIG. 1). The control unit contains circuitry that applies voltage to the electrical ram subsystem via manipulation of an input device such as a joystick, rheostat, potentiometer, push buttons and the like. For ease of use, the input device is preferably a joystick.
The photo below is looking at the car from the rear. Basically, the ram, 240, pushes one of the knuckles/wheel carriers, which rotates, pushes/pulls the tie rod connecting to the other knuckle/wheel carrier, thus turning that wheel, too.
So there you are, tipster named Sam. Your agonizing can come to an end. You may now know the freedom that comes only with true enlightenment in the area of rear-steered Controlled Slide Cars.
I, meanwhile, just wasted far too much time on this and probably should be doing something more important. But happy to be of service.
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There used to be a Class A RV made with 4 wheel steering. You should get Mercedes to run one down and you could make it the moving command center for The Autopian.
I recognize this spot as a local. Same parking lot area they do auto X at the Brewers stadium. That area, Canal street & immediate industrial zone around there are fun to rip around on when it’s off hours. I43 S down to Mercedes home state and back are also enjoyable as well.
Based on my experience the Sonic could use 4WS. The thing has a pretty large turning radius for something so small.
Back in high school we figured out a much cheaper way to induce oversteer in a FWD car, it only cost a couple lunch trays from the cafeteria.
The Burger King and McDonald’s by my high school stopped giving trays to anyone who looked under the age of 25 because so many of them ended up under the back wheels of everyone’s FWD crapboxes. Boy did we have a lot of fun tray-sliding my friend’s first-gen Integra…
Same.
Now I’d love to do this at a Sonic — in a Sonic — just for the retro-lulz. While playing Sonic. And listening to Sonic…Youth.
There used to be a company that made Skid Monster. https://www.youtube.com/watch?v=z4zDY5xjXIo Years ago there was a driving school that used the parking lot of the community college near my house to do their training. The way that system works is that the instructor can lock the wheels in the straight ahead position or unlock them at will. It was interesting the glimpses I’d catch when driving by as they would have them drive across a sloped part of the parking lot and randomly unlock the casters.
That must be the most expensive Chevy Sonic ever made.
Also the coolest.