Prius Chat Friends, I am training my daughter to drive. She wrecked my Crown Vic by abruptly rotating the steering wheel half a turn to abort a lane change, causing a skid from which she was not able to recover. Likely three cars were a total loss and another sideswiped. BTW, the Ford oversteers, which is useful to a highly skilled driver, but was less than helpful to us. My question: What happens if you get a Prius going 60 MPH, then spin the steering wheel half a turn? i.e. Is the tendency to oversteer or understeer? Assuming the excessive initial control input mentioned, what is the correct set of control inputs of the steering, brake and throttle controls to recover? My knowledge of front wheel drive handling is limited. A suitable training facility is not available, so it looks like we will have to learn from books, not in-car experiences. thanks, Peter
The Prius has VSC. It will do its best with selective braking and power modulation to avoid any loss of control. Tom
Yes, I see that VSC may reduce power and/or apply brakes. However, this still doesn'y answer the question of how to to steer in this situation, or when to increase power. I guess I can wait for winter and find an icy parking lot, but I am interested in knowing sooner, to help understand how to steer out of this potential situation. Sadly, given that this driving error has already happened once, it might be repeated.
Where are you located? Some areas have car clubs that let you practice all sorts of maneuvers safely, on a track. Example is Northwest Alfa Romeo Club :: Welcome. No, you don't need to have an Alfa. I went to one of their Northwest Alfa Romeo Club :: Track Events events before. IIRC, there were some teens there w/their parents.
It varies on the situation though. The point of the VSC is to help mitigate some of the skidding by adjusting those wheels, steering wise, you try to turn the car towards the direction you are trying to go. The thing is, the steering practices and power adjustments are more for cars without skid/traction control safety features, which we can't really give you 'proper' ones per say because the systems will mitigate the need for it. The thing most people should be doing in a situation of that should be braking or reducing power in general than 'power through'. There is no real 'ideal' way to do it unless you want to take a professional driver's course and doing those very specific conditions. Unfortunately, this may not be the best place for the question at hand.
With VSC you steer where you want to go. That's just the point: the driver tells the car where to go, and the car figures out how to do it. Without VSC, most front wheel drive cars will under steer. To get out of a skid, point the wheels down the road (turn into the skid) and apply even accelerator. Too much gas will cause the front wheels to spin; too little gas will cause them to skid. Either leads to a loss of control. With VSC and ABS you want to teach people to keep driving and steer around any obstacles. Instead of focusing on technique, you focus on driving: steer, and brake if you need to. Tom
The whole experience of crossing all lanes of traffic, striking the guardrail at about 40 MPH, then being subsequently struck by a pickup truck at speed, was not a pleasing experience. After the wrecks got hauled onto the flatbeds, a Virginia State Trooper gave us a ride to a nearby hotel. On the way, he described the training he had received: dry skids, wet skids, gravel skids and even dirt skids. In his training, he was required to push the car beyond its limits, then recover. There is a somewhat similar course for civilians nearby. However, to enter the training course, you need to already have a full license, not a learner's permit. Obviously, training now would be better. The impression I am left with is that many drivers have no idea what happens when you abruptly spin the wheel at 60 MPH; they simply avoid doing that. The car club suggestion is one I've considered. There is an autocross club here. The way I understand it works locally is that they arrange a large parking lot at the Redskins football stadium, and you spend the day, getting two or three 30 second runs through cones.
This is exactly right. My son took a course in emergency handling on a race track with our Gen II Prius, and the instructors asked me if I knew how to disable the VSC to permit realistic training. I didn't, and subsequently rode with my son during a variety of maneuvers, including sudden lane changes, high-speed cornering, and panic stops. It's very difficult to get the car to become uncontrollable. You place your vote about what you want the car to do, and the computers make appropriate adjustments to keep it from going out of control. VSC is really impressive in these situations, and probably most important for youthful, inexperienced drivers.
Tom, In the particular crash, she first steered hard right. As the back end started to come around, she steered into the skid as you suggest, hard left. As is too typical, the correction then launched the car across all lanes, spinning out in the opposite direction. The back end was slightly ahead of the front end when we struck the center guard rail. After perhaps continuing to spin or being struck lightly by two other cars, the passenger side faced oncoming traffic and was struck by the pickup truck. I think you are right, steer in the direction to want the front of the car to go. However, an untrained driver has trouble with the feel of when to reduce the "steer into the skid" correction when it is starting to be effective. Racers sometimes say "There is no overcorrecting, only being too slow." For a severe skid, several different steering inputs may be required as the pilot "gathers it in" to reduce the fishtailing, which is essentially a pilot-induced oscillation. The design of the control system does make a difference, but experience also plays a hand. I guess she is continuing a family tradition. I once spun my Austin Healey Sprite on a lane change. Had a large passenger and the front/rear weight ratio had changed. thanks much, Peter
Rob, Kudos; sounds like your son is well trained. I had considered karting, but what you describe, using the actual vehicle with the actual mode (VSC on) sounds more realistic. Now, I need to find a good course. Autocross just doesn't sound exactly right. Peter
Despite the value this training provides, I don't necessarily recommend it. For some drivers, I think it reduces risk aversion, which might lead to needless accidents. I suspect this is the reason many insurance companies refuse to endorse this kind of training, conducted by racing drivers. Perhaps something conducted by AAA would be better, if available.
This is classic over-control, or driver induced oscillation. The driver corrects for a skid, but fails to remove the correction expeditiously and induces a skid in the other direction. The driver then over-corrects for that skid, returning the cycle to its initial state, but often at higher amplitude. The cycle continues until the car hits something. We learn all about this sort of driving from an early age, given our snowy winters. Without VSC it takes technique and practice. With VSC it's hard to get into a skid. Tom
Time to hit the gravel roads. If you know somebody with a grass field, use that for practice. Gravel roads will eat up paint, so use your worst car for that. Snowy roads are the best. If you have more time and money, autocross and other teaching venues as already mentioned would be great. My best learning was done on gravel roads as a kid and in snow. Just make sure to stay away from deep ditches where ever you do your practicing.
When you drive a car completely ham-fisted, recovery isn't always possible. If you yank the wheel hard at speed, any car is going to go into an unrecoverable spin. There isn't a car on earth that's going to make an instant 90* turn at 60+mph, and when you've got that much momentum behind the slide, the car is going to rotate so fast that it's going to be physically impossible (especially in a car with a slow steering ratio, high center of gravity, and soft suspension) to crank the wheel back fast enough to counter steer. Training her to drive should focus on accident avoidance without over-steering. If her first reaction is to yank the wheel as far and hard to the side as she can, the situation is doomed from the start. Your best bet for teaching general car control safety is snow driving. It's the only way to pratice at the limit handling while moving at low enough speeds that things happen slowly enough that reactions can be thought through, rather than relying on instinct. If all that fails, the counter intuitive solution that will fix 90% of skids (in cars that don't make much power), just floor it. It will stablize the car while you counter steer, sometimes even without counter-steering and will help prevent over-correction.
The other problem is that in some cases, using that method incorrectly, especially on cars that have a higher center of gravity, like SUVs, it is easier to 'roll' them as well as trying to correct a skid. The Prius cars shouldn't have a high center of gravity, but I think that is part of the reason why it isn't really encouraged nearly as much.
