Wonder why your car shifter is getting PRND? There is a good reason
welcome to More details, a series dedicated to the ubiquitous but little-known elements hidden on your favorite products. This week: something about your car’s automatic transmission that you might never have noticed.
If your car has an automatic transmission, the different positions you can shift to follow a specific pattern: PRND, usually followed by a few lower gear options or the ability to switch to manual control mode. In case you’ve never driven (or somehow only driven manual transmission cars, where, God bless you), these four letters mean Parking, reverse, neutral and Drive – or, in simple terms, Stopped, Back, Free-Roll and Before.
You’ve probably gone from Park to Drive a hundred thousand times, and from Drive to Reverse almost as much. But during all these times, have you ever wondered: Gee, why is it that every car’s shifter seems to shift from reverse to neutral when driving?
Well, there is actually a very good reason: the United States government says so.
When automatic transmission was young, automakers often installed their own gear levers, but they really wanted to. A common provision, found in General Motors and Chrysler models, among others, placed reverse gear at the end of the shifter, after neutral, driving and lower gears. In a way, it made sense; after all, you want reverse gear to be easy to find, so why not put it at the very end of the shift lever?
The problem that arose, however, was one of user error: people attempting to shift into low forward gear would end up overtaking in reverse without realizing it, or vice versa. Given the mass of, say, an eldorado of 59, suddenly traveling in the wrong direction could have very unpleasant consequences for people, animals or objects in the way.
It didn’t take anyone other than acclaimed security advocate Ralph Nader to help shed light on the issues with this arrangement. In the second chapter of his flagship book Dangerous at any speedNader spoke of five headline-grabbing examples of death, injury and destruction caused by the poorly designed PNDLR change arrangement.
“It takes no science and little forethought to accurately condemn a particularly dangerous shifting pattern – the PNDLR quadrant common to Cadillac, Buick, Oldsmobile, Pontiac, Studebakers and Ramblers over the past decade,” he said. -he writes. “The driver is obliged to see the gear lever to confirm the gear used. The driver must lift the lever to shift into reverse. If it does not raise it enough, the car will stay in the front low position while the driver looks back and expects the car to move in that direction.
Staying neutral between forward and reverse, Nader said, was a commonly accepted feature of mechanical design in things like power tools. But the design of the Hydra-matic transmission used in these models made it cheaper to reverse next to the front gears, according to an automotive transmission engineer cited by Nader; when that obstacle had disappeared in 1956, GM would have backed it up – using the rather circular reasoning that, indeed, there were already too many cars on the road using the PNDLR setup to stop using it now.
As if to encourage the adoption of seat belts, Nader’s outspoken advocacy ended up paying off. While American automakers all embraced the superior design of putting neutral between reverse and drive in 1966, in 1971 it was part of federal law in the form of US Department of Transportation Standard No. 102: “Location of the gear change positions on passenger cars. A neutral position must be located between the forward and reverse positions.
The recent return of push-button transmission selectors and the advent of electronic gearshifts mean that automakers have a bit more flexibility than ever before, in terms of the layout of the controls. Honda and Lincoln’s push-button shifters organize his choices vertically; GMC extends them horizontally; Mercedes-Benz, Bmw, Hyundai and Ford, among other things, make Park a separate search button. But the heart of the rule remains in force: if you want to switch from Drive to Reverse or vice versa, you must stop in Neutral.
Now some exotic cars with automated single-clutch and dual-clutch manual transmissions, like Ferrari, Lamborghini and Mclaren, arrange things even more differently – but that seems to be due to the fact that they do without a “Park” or, in some cases, even a “Drive”. (Ferrari, for example, only offer buttons for reverse and manual modes; neutral is achieved by pulling both paddle shifters at the same time, and parking occurs automatically when the car is turned off.)
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