# Is it necessary/prudent to use parking brake? **URL:** \ **Category:** Factual Questions\ **Created:** [May 23, 2006, 12:49am UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844 "2006-05-23T00:49:17Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [May 24, 2006, 4:26pm UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/21 "2006-05-24T16:26:41Z")
> [@Asimovian](#): > > Without delving into any other aspect of this issue, I don’t know that most people have any idea how their car would react to applying the emergency brake while the vehicle is in motion. I certainly don’t, and the idea of possibly losing control in that situation scares me a bit. > > How did you figure out how far to pull up on the brake handle to slow down without, you know, screeching tires and what-not? Same way you figure out how hard to press on the service brake pedal to slow down without screeching to a stop - apply force gradually, and ease up or apply harder as needed. It can also be done with a pedal-operated parking brake with a separate release handle, but it’s trickier in that you have to keep the release handle pulled out the whole time so you can ease up as desired. I’ve never done it with a pedal-operated “push again to release” design, and wouldn’t recommend it. On a straight, dry road, I’ve never experienced any hint of losing control. Keep in mind we’re talking about a gradual apply, not suddenly yanking it all the way. On a slick road, or a curve, I would be concerned about possibly going into a skid. One technique for a bootleg turn, called the handbrake turn, is to yank the steering wheel and then immediately yank the handbrake on. You can spin 180 degrees mighty quick. It’s fun to mess around with at 5 or 10 mph in a snow-covered parking lot, but I wouldn’t want to experience it during normal driving. ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [May 24, 2006, 7:53pm UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/22 "2006-05-24T19:53:15Z")
> [@KlondikeGeoff](#): > > 1. I’ve read several times that parking on a really steep hill using just the Park w/auto transmission, may break or weaken the pawl, and then off ya’ go. Perhaps transmission pawls are stronger now. > > 2. IIRC, in San Francisco it is required that a car have the parking break on as well as be in Park with auto and in gear in manual. It may have changed now, but why take a chance? I almost got killed because of this, when I was a kid. The parking lot was on a hill. I was in the back seat, and was going to get out on the drivers side when my Mom told me to get out of the passengers side, facing down the hill. Just as I closed the door the car jerked - a car, parked up the hill without a parking brake, rolled down and hit our car on the rear driver’s side door. :eek: I don’t know what type of transmission he had. ---
**Author:** ![PoorYorick](https://avatars.discourse-cdn.com/v4/letter/p/ecccb3/32.png) [@PoorYorick](https://boards.straightdope.com/u/PoorYorick)\ **Post date:** [May 24, 2006, 8:10pm UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/23 "2006-05-24T20:10:39Z")
> [@Gary T](#): > > The parking brake is redundant on a car with an automatic transmission that is in park. It’s somewhat redundant on a manual transmission car that is left in gear. However, redundancy is not necessarily a bad thing, and it’s a significant aspect of many safety systems. The day may come when the key comes out of the ignition even though the car is not in park, or when the parking pawl doesn’t engage properly, or when the (manual) trans is left in neutral. Am I the only idiot who had to look up the definition of [pawl](http://www.webster.com/cgi-bin/dictionary?sourceid=Mozilla-search&va=pawl)? ---
**Author:** ![Sean\_Factotum](https://avatars.discourse-cdn.com/v4/letter/s/50afbb/32.png) [@Sean\_Factotum](https://boards.straightdope.com/u/Sean_Factotum)\ **Post date:** [May 24, 2006, 8:32pm UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/24 "2006-05-24T20:32:17Z")
My dad, a transmission man for GM dealerships for several decades, always advocated using the parking brake on a hill. Make sure, he said, to engage the parking brake _before_ putting the automatic transmission to Park. It prevent putting the weight of the car on bits and pieces inside the transmission, which will cause premature failure of the transmission. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [May 24, 2006, 9:27pm UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/25 "2006-05-24T21:27:40Z")
> [@](#): > > Originally Posted by **Sean Factotum** > _My dad, a transmission man for GM dealerships for several decades, always advocated using the parking brake on a hill. Make sure, he said, to engage the parking brake before putting the automatic transmission to Park. It prevent putting the weight of the car on bits and pieces inside the transmission, which will cause premature failure of the transmission._ The manual for my car (an automatic transmission Ford Taurus) recommends _always_ engaging the parking brake before shifting to park. For the same reason, to reduce stress on the transmission. Why put unneeded tension on the tranny? ---
**Author:** ![Lagavulin](https://avatars.discourse-cdn.com/v4/letter/l/ea5d25/32.png) [@Lagavulin](https://boards.straightdope.com/u/Lagavulin)\ **Post date:** [May 24, 2006, 10:14pm UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/26 "2006-05-24T22:14:22Z")
During nearly 22 years of driving in America I only used the parking brake if I was parking on an incline. I live in the UK now and recently had to get a UK driving license. I took a few lessons before the test and was told to use the parking brake any time I came to a stop, incline or not, and not just if I was parking. And during the practical test, one of the manuevers is a hill start, which involves a delicate balancing act of gas, clutch and parking brake. You roll backward even an inch, you fail the whole test. ---
**Author:** ![Nanoda](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Nanoda](https://boards.straightdope.com/u/Nanoda)\ **Post date:** [May 25, 2006, 1:14am UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/27 "2006-05-25T01:14:36Z")
I almost always use my brake when parking (and also in winter so I can ‘drift’ out of the office parking lot), but I hadn’t used it on dry roads to stop my car. My '04 Chevy Malibu has the pedal type **Gary T** echews, but in the interests of experimentation I used it on the way home today. From about 35 kph using a medium setting, it did slow the car (but at a rate far slower than that of the regular brakes, of course). Contrary to **kanicbird** ’s post though (and to my initial thinking), when I really punched it down (though it could probably go furthur), I _did_ lock the rear wheels - quite noisily, right in the middle of our quiet crecent, too :o. ---
**Author:** ![MrFantsyPants](https://avatars.discourse-cdn.com/v4/letter/m/7ba0ec/32.png) [@MrFantsyPants](https://boards.straightdope.com/u/MrFantsyPants)\ **Post date:** [May 25, 2006, 2:21am UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/28 "2006-05-25T02:21:05Z")
If I recall correctly, on some models of car, the parking brake is used to help keep the rear drum brakes well calibrated. I thought it was some GM vehicles, but not terribly sure. So, there’s another good reason to use it. ---
**Author:** ![Critical1](https://avatars.discourse-cdn.com/v4/letter/c/3e96dc/32.png) [@Critical1](https://boards.straightdope.com/u/Critical1)\ **Post date:** [May 25, 2006, 6:17am UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/29 "2006-05-25T06:17:56Z")
> [@Lagavulin](#): > > And during the practical test, one of the manuevers is a hill start, which involves a delicate balancing act of gas, clutch and parking brake. You roll backward even an inch, you fail the whole test. back when I had a stick I would do this with just the pedals, left foot clutch, right foot heel on the brake and toes on the gas…of course I was a smart ass kid back then and would prpbably just use the hand brake for simplicities sake nowadays ---
**Author:** ![Declan](https://avatars.discourse-cdn.com/v4/letter/d/ecae2f/32.png) [@Declan](https://boards.straightdope.com/u/Declan)\ **Post date:** [May 25, 2006, 6:43am UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/30 "2006-05-25T06:43:12Z")
I checked with the research boys at work, the park and hand brake are both designed with having a wire that runs to the rear wheels of the car, for both GM and DCX series of Brake systems that we manufactur. He also said that he was not aware of any vehicle that had the aux brake hooked up to the front wheels. Yorick A Pawl is simply a little gear, in the hand brake, thats about the size of a nickel, and has about 7 teeth, that inter connect with a pinion, thats about the size of a walnut, but has gear teeth around its circumference and keeps the brake handle from releasing ,without pushing the button. Declan ---
**Author:** ![Martini\_Enfield](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/martini_enfield/32/11123_2.png) [@Martini\_Enfield](https://boards.straightdope.com/u/Martini_Enfield)\ **Post date:** [May 25, 2006, 8:04am UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/31 "2006-05-25T08:04:04Z")
> [@Gary T](#): > > Greater than zero. > > In Russian Roulette, your chance of getting the bullet is about 15%. But if you’re in that unlucky 15%, you’re 100% dead. Assuming you’re playing with a standard, six-shot revolver, of course! If you’re playing it _a la Russe_, you’d be using a Nagant M1895 revolver- which holds **seven** shots. It’s also nearly impossible to “free spin” the cylinder on the Nagant N1895, but that’s getting off-topic. 😉 Back on topic, using the handbrake is a good thing- as others have said, it gives you extra security (knowing your car can’t roll away), not to mention there are certain driving manouevres that are facilitated by the judicious use of the handbrake at the appropriate moment… 😃 ---
**Author:** ![PoorYorick](https://avatars.discourse-cdn.com/v4/letter/p/ecccb3/32.png) [@PoorYorick](https://boards.straightdope.com/u/PoorYorick)\ **Post date:** [May 25, 2006, 1:10pm UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/32 "2006-05-25T13:10:23Z")
> [@Declan](#): > > Yorick > > A Pawl is simply a little gear, in the hand brake, thats about the size of a nickel, and has about 7 teeth, that inter connect with a pinion, thats about the size of a walnut, but has gear teeth around its circumference and keeps the brake handle from releasing ,without pushing the button. > > Declan Many thanks, **Declan**. ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [May 25, 2006, 1:46pm UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/33 "2006-05-25T13:46:35Z")
To clarify the meaning(s) of _pawl_: A pawl is little lever that engages into teeth on a wheel (or part thereof) to prevent motion of the wheel. The “park” function on automatic transmissions is achieved by a pawl that engages into a toothed wheel which is contiguous with the tranny output shaft. It prevents the wheel (and shaft) from rotating in either direction. This is what I referred to in post #5, and thought maybe **racer72** was referring to in post #11\*. In post #30, **Declan** is referring to a [ratchet wheel and pawl](http://www.webster.com/mw/art/ratchetw.htm) as used in a handbrake lever, which has not yet been part of the discussion here. The “little gear” he mentions is not actually the pawl, but the ratchet wheel (or more correctly ratchet quadrant) that works with the pawl. In contrast to the design of a transmission’s parking pawl, this design permits motion in one direction but not the other, until the pawl is released (by pressing the button in the handbrake lever). This is the set-up used in ratchet wrenches and clock movements. * * * \*I now suspect **racer** was seeing an ABS tone ring and mistook it for a ratchet wheel, and postulated but never saw a pawl (because there isn’t one). I also suspect he did apply the parking brake rather than shifting into park, and that the parking brake only functioned on the left rear side. ---
**Author:** ![js\_africanus](https://avatars.discourse-cdn.com/v4/letter/j/87869e/32.png) [@js\_africanus](https://boards.straightdope.com/u/js_africanus)\ **Post date:** [May 25, 2006, 2:13pm UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/34 "2006-05-25T14:13:22Z")
On some cars, so I’m told, the parking brake actually calibrates the regular brake, so that not using it can result in the brakes not applying the proper pressure when one presses the brake pedal. I’ve been told this by a couple of brake shops, so I assume it’s accurate; however, _caveat lector_. ---
**Author:** ![xiix](https://avatars.discourse-cdn.com/v4/letter/x/d6d6ee/32.png) [@xiix](https://boards.straightdope.com/u/xiix)\ **Post date:** [May 25, 2006, 2:24pm UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/35 "2006-05-25T14:24:56Z")
Perhaps I should have phrased the question like this: On a modern '06 vehicle, is there a significant (above oh, 1 in 10000) chance that my breaks will fail and the parking brake if on at the time would stop the car from rolling down a hill? I find it hard to believe that breaks on a modern car could fail. ---
**Author:** ![UncleBeer](https://avatars.discourse-cdn.com/v4/letter/u/977dab/32.png) [@UncleBeer](https://boards.straightdope.com/u/UncleBeer)\ **Post date:** [May 25, 2006, 2:49pm UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/36 "2006-05-25T14:49:01Z")
Any mechanical device can fail. But that has nothing to do with your brakes failing in a sloped parking lot on a stationary car. When you park your car, the “regular” brakes simply are not engaged. ---
**Author:** ![jbarro](https://avatars.discourse-cdn.com/v4/letter/j/9de0a6/32.png) [@jbarro](https://boards.straightdope.com/u/jbarro)\ **Post date:** [May 25, 2006, 9:56pm UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/37 "2006-05-25T21:56:06Z")
> [@Sean Factotum](#): > > My dad, a transmission man for GM dealerships for several decades, always advocated using the parking brake on a hill. Make sure, he said, to engage the parking brake _before_ putting the automatic transmission to Park. It prevent putting the weight of the car on bits and pieces inside the transmission, which will cause premature failure of the transmission. Thank you! I read in my driver’s manual to always put the parking brake on before switching to Park in my car, but my husband always does it the opposite way (he says he can’t imagine it makes any difference). Now I can explain it to him with a good reason. ---
**Author:** ![GorillaMan](https://avatars.discourse-cdn.com/v4/letter/g/50afbb/32.png) [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)\ **Post date:** [May 25, 2006, 10:20pm UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/38 "2006-05-25T22:20:10Z")
> [@Lagavulin](#): > > I live in the UK now and recently had to get a UK driving license. I took a few lessons before the test and was told to use the parking brake any time I came to a stop, incline or not, and not just if I was parking. And during the practical test, one of the manuevers is a hill start, which involves a delicate balancing act of gas, clutch and parking brake. You roll backward even an inch, you fail the whole test. Part of this comes from the predominance of manual transmission in the UK. My instructor explained to me a good reason for applying the handbrake when stopped in traffic: if someone hits you from behind, it’s their fault, but it still gives you a lot less bureaucratic insurance hassle if your car doesn’t then shunt into the one in front. Never mind the possibility of shunting into someone walking between the cars, or whatever else. Nice username, by the way 🙂 ---
**Author:** ![jjimm](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@jjimm](https://boards.straightdope.com/u/jjimm)\ **Post date:** [May 25, 2006, 10:24pm UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/39 "2006-05-25T22:24:41Z")
> [@xiix](#): > > no its an automatic…but what is the likelihood of my primary brake failing on me? Because I don’t believe it’s a primary brake - on an automatic it’s your clutch engaged with the engine that vaguely immobilises the car. ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [May 25, 2006, 11:11pm UTC](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844/40 "2006-05-25T23:11:52Z")
> [@xiix](#): > > Perhaps I should have phrased the question like this: On a modern '06 vehicle, is there a significant (above oh, 1 in 10000) chance that my breaks will fail and the parking brake if on at the time would stop the car from rolling down a hill? > > I find it hard to believe that breaks on a modern car could fail. Oh, anything can (and does) fail on at least some cars, but yes, modern cars are overall quite a bit more reliable than those of decades ago. Let’s separate this into two components: When you’re driving the car, you use the service brakes (normally just called “the brakes”) to slow down and stop. Conceivably you could have a failure of the service brakes (somewhat rare but certainly not unheard of nor impossible) and in such a situation the parking brake could be used as an emergency brake. It has nowhere near the stopping power of the service brakes but it’s certainly better than nothing. When you’ve parked the car, it is normally immobilized by the transmission being in “park.” This has nothing to do with any part of the brake system. Applying the parking brake is a back-up for the very rare instances where for some reason the (transmission) park setting fails to immobilize the car. There is probably a much less than 1 in 10,000 chance of this being an issue. What many of have suggested in this thread, though, is that even though there’s not much reason to apply the parking brake to keep a parked car from rolling down a hill, there are other benefits to applying it routinely. [Previous page](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844.md?page=1) [Next page](https://boards.straightdope.com/t/is-it-necessary-prudent-to-use-parking-brake/357844.md?page=3)