# Auto transmission drives without foot on the pedal. Why is this still an issue? **URL:** \ **Category:** Factual Questions\ **Created:** [March 28, 2016, 7:12pm UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477 "2016-03-28T19:12:55Z")\ **Posts on this page:** 15\ **Page:** 6
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [March 31, 2016, 11:13pm UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477/101 "2016-03-31T23:13:28Z")
> [@Machine\_Elf](#): > > If your 10-MPH riding lawn mower stops dead in the middle of your yard, there’s no problem. > > If you’re doing 75 MPH on the interstate when you lift your butt of the seat to scratch your ass or fish for the Skittles you just dropped, and the engine shuts down or the brakes kick in, you’ve got a Major Problem. Absolutely. However, you have created a situation unrelated to the OP. Lets review the original criteria: After the vehicle has been engaged in “normal” driving operation then, (and) with engine at or near idle, (and) ground speed is VERY low, (and) door is open, (and) seat sensor indicates it is unoccupied, (and) transmission is engaged in (not) park… Then a safety interlock is activated. My logic string may be imperfect, but the point is, this scenario is controllable. Confusing the issue at hand, with the complicating factors involved in the act of ass scratching @ 75 MPH, is immaterial (and non effectual) in this case. > [@kayaker](#): > > Yeah, that’s one of the safety interlocks I’ve disabled on our Kubota. My gf barely weighs enough to be detected. If she shifts her weight even slightly (like you do mowing a mild grade) the tractor used to shut down. Understood. But faulty engineering on behalf of the manufacturer does not negate the original intent and validity of the notion. Perhaps you need to feed your gf a little more.😃 ---
**Author:** ![SpyOne](https://avatars.discourse-cdn.com/v4/letter/s/82dd89/32.png) [@SpyOne](https://boards.straightdope.com/u/SpyOne)\ **Post date:** [April 1, 2016, 12:43am UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477/102 "2016-04-01T00:43:50Z")
Ignore this. (Handled by a Mod, didn’t mean to pile-on.) ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [April 1, 2016, 12:50am UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477/103 "2016-04-01T00:50:27Z")
SUccessful man/machine interface design also depends on simplicity. We fight this a bunch in aviation. The engineers can conceive of a chain of 12 if/then’s that result in the ideal behavior for the circumstances. But to us operators the damn thing seems to have a random mind of its own because there’s always one more subtle distinction you forgot about in your systems knowledge or you didn’t notice applied to the current circumstances. It’s also often the case that the sanitized version of reality the engineers designed to doesn’t match the unsanitary reality we operate in. So some modes they expected would be exceedingly rare become the most common ones and vice versa. Given how few people know anything about their car except how to start it and push two pedals (usually not simultaneously), and steer sorta, I’m not thinking that \*subtle \*is a very good design goal. ---
**Author:** ![SpyOne](https://avatars.discourse-cdn.com/v4/letter/s/82dd89/32.png) [@SpyOne](https://boards.straightdope.com/u/SpyOne)\ **Post date:** [April 1, 2016, 1:10am UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477/104 "2016-04-01T01:10:38Z")
> [@ZurBob](#): > > Manufacturers of riding lawnmowers and heavy equipment such as fork trucks solved this concern years ago. Agree with the concept or not, driver’s seat occupancy sensors stop the engine (or lock the transmission/brakes) when the seat is vacated. Inclusion of this scheme in the auto world would address the OPs question, and by today’s standard, would not involve cutting edge technology and development, nor require much expense on behalf of the manufacturers to implement if they so choose. > > They choose not to. So be it. Years ago I was reading a car magazine and on the letters page a guy had written in to ask about a part on his car he couldn’t identify. He had bought a classic muscle car, and it had a box mounted to the firewall, but the wires that came out of it didn’t attach to anything and he could not find mention of it in the manuals. The editors identified it immediately, and said it came on only one model year of car. See, in the early 1970s, Congress decided to require that the driver’s seatbelt be buckled to start the engine. The editors explained that this law lasted roughly “Until members of Congress began taking delivery of (model year) cars.” It was an idea that looked good on paper, but had same annoying drawbacks in practice. Sort of like the sensors that sounded a warning buzzer if the front seats were occupied but the belt wasn’t buckled. Which is why my neighbor had to buckle in their groceries in a 1970 Ford. An interlock that shuts off the engine if the seat is unoccupied sounds decent on a brand-new car. I have never owned a brand-new car. I have, however, owned cars that were particularly hard to start. Hard enough to start that I would leave the engine running (and lock the doors) when I went into a store. An interlock that shuts the engine off if I get out of the driver’s seat is a feature I would pay extra not to have, right up there with headlights you can’t turn off. ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [April 1, 2016, 1:49am UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477/105 "2016-04-01T01:49:55Z")
> [@SpyOne](#): > > Years ago I was reading a car magazine and on the letters page a guy had written in to ask about a part on his car he couldn’t identify. He had bought a classic muscle car, and it had a box mounted to the firewall, but the wires that came out of it didn’t attach to anything and he could not find mention of it in the manuals. > The editors identified it immediately, and said it came on only one model year of car. > See, in the early 1970s, Congress decided to require that the driver’s seatbelt be buckled to start the engine. > The editors explained that this law lasted roughly “Until members of Congress began taking delivery of (model year) cars.” It was an idea that looked good on paper, but had same annoying drawbacks in practice. > > Sort of like the sensors that sounded a warning buzzer if the front seats were occupied but the belt wasn’t buckled. Which is why my neighbor had to buckle in their groceries in a 1970 Ford. > > An interlock that shuts off the engine if the seat is unoccupied sounds decent on a brand-new car. I have never owned a brand-new car. I have, however, owned cars that were particularly hard to start. Hard enough to start that I would leave the engine running (and lock the doors) when I went into a store. > An interlock that shuts the engine off if I get out of the driver’s seat is a feature I would pay extra not to have, right up there with headlights you can’t turn off. Again, reading comprehension. Engine ON, tranny IN DRIVE, door OPEN, with seat UNOCCUPIED… What part of this statement is difficult to understand? ---
**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:** [April 1, 2016, 4:29am UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477/106 "2016-04-01T04:29:42Z")
> [@ZurBob](#): > > Manufacturers of riding lawnmowers and heavy equipment such as fork trucks solved this concern years ago. Agree with the concept or not, driver’s seat occupancy sensors stop the engine (or lock the transmission/brakes) when the seat is vacated. Inclusion of this scheme in the auto world would address the OPs question, and by today’s standard, would not involve cutting edge technology and development, nor require much expense on behalf of the manufacturers to implement if they so choose. > [@ZurBob](#): > > Engine ON, tranny IN DRIVE, door OPEN, with seat UNOCCUPIED… What part of this statement is difficult to understand? The parts that weren’t in your first post above, which mentions only the seat. ---
**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:** [April 1, 2016, 4:35am UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477/107 "2016-04-01T04:35:49Z")
> [@HoneyBadgerDC](#): > > A young girl was killed at a drive through a couple of days ago when she dropped something at the pick up window and opened her door to reach down and pick it up, her foot came off the brake and car went forward trapping her. > [@Telemark](#): > > Here’s the story - [http://myfox8.com/2016/03/24/28-year-old-woman-killed-in-freak-accident-at-drive-thru/](http://myfox8.com/2016/03/24/28-year-old-woman-killed-in-freak-accident-at-drive-thru/) I read the story and watched the video and still haven’t figured out how she got pinned between the car and the building. Can anyone enlighten me? ---
**Author:** ![UDS](https://avatars.discourse-cdn.com/v4/letter/u/ecae2f/32.png) [@UDS](https://boards.straightdope.com/u/UDS)\ **Post date:** [April 1, 2016, 4:48am UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477/108 "2016-04-01T04:48:42Z")
> [@Gary\_T](#): > > I read the story and watched the video and still haven’t figured out how she got pinned between the car and the building. Can anyone enlighten me? Well, at a guess: When the car went forward it didn’t travel parallel to the wall, but drove into the wall at an angle. Possibly the car was aligned at an angle to begin with; possibly the driver still had her hand on the wheel and it turned when the car began to move (and she, with one foot on the ground, didn’t); possibly she grabbed the wheel in a panic. Anyway, the car moved forward and closer to the wall. The door was open and the driver was partly out, leaning down to recover what had been dropped. The open door would be the first, or one of the first, things to strike the wall. It would then pin her, possibly by the head or neck, and continue to close, compressing or choking her, until the car came to a halt, most likely when the front driver-side wing hit the building. ---
**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:** [April 1, 2016, 4:59am UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477/109 "2016-04-01T04:59:49Z")
> [@UDS](#): > > Well, at a guess: > > When the car went forward it didn’t travel parallel to the wall, but drove into the wall at an angle. Possibly the car was aligned at an angle to begin with; possibly the driver still had her hand on the wheel and it turned when the car began to move (and she, with one foot on the ground, didn’t); possibly she grabbed the wheel in a panic. > > Anyway, the car moved forward and closer to the wall. The door was open and the driver was partly out, leaning down to recover what had been dropped. The open door would be the first, or one of the first, things to strike the wall. It would then pin her, possibly by the head or neck, and continue to close, compressing or choking her, until the car came to a halt, most likely when the front driver-side wing hit the building. I can see that, but I can’t see how it could be described as her being pinned between the car and the building, which is what someone said in the video. That’s being pinned between the door and the door jamb. Maybe they were just being sloppy with their words. ---
**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:** [April 1, 2016, 5:08am UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477/110 "2016-04-01T05:08:33Z")
Or maybe I’m being too picky about it. It’s late and I’m tired. **UDS** is probably right. Good night. ---
**Author:** ![SpyOne](https://avatars.discourse-cdn.com/v4/letter/s/82dd89/32.png) [@SpyOne](https://boards.straightdope.com/u/SpyOne)\ **Post date:** [April 1, 2016, 5:29pm UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477/111 "2016-04-01T17:29:08Z")
> [@ZurBob](#): > > Again, reading comprehension. > > Engine ON, tranny IN DRIVE, door OPEN, with seat UNOCCUPIED… What part of this statement is difficult to understand? How about that that isn’t what you said. > [@ZurBob](#): > > …driver’s seat occupancy sensors stop the engine (or lock the transmission/brakes) when the seat is vacated. I don’t see anything I did that justifies your attitude. ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [April 1, 2016, 11:54pm UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477/112 "2016-04-01T23:54:29Z")
> [@SpyOne](#): > > How about that that isn’t what you said. > > I don’t see anything I did that justifies your attitude. To be clear: I’m not advocating for any new interlocks to be introduced. My posts on the topic were intended to comment on what appeared to be two consensus trends that developed here. One, being the opinion that the OP’s scenario could not be practically addressed, and two, the general nasty tone of the replies the OP has generated. In the course of this, there seemed to be quite a few comments that ran off the tracks of relevancy as related to the OP. Hence my comment on “comprehension”. Sorry if you got caught up in my generalization of such. I was merely trying to make the point that random inclusion of new sensors, (a seat occupancy sensor in this case) was not the point. Rather, how it could be incorporated in a logical fashion to address the OP, and ONLY the OP. ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [April 2, 2016, 12:22am UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477/113 "2016-04-02T00:22:16Z")
> [@Gary\_T](#): > > The parts that weren’t in your first post above, which mentions only the seat. Read the thread. I didn’t delineate the logic sequence of my seat sensor suggestion as related to the OP in my EVERY post, sorry. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [April 2, 2016, 1:23am UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477/114 "2016-04-02T01:23:49Z")
There is a seatbelt sensor in most cars, and there are door sensors in most cars, so a simple switch that prevents the car from moving itself forward if both of those switches are open. Automatics cannot be push-started nearly as easily as a manual, and creep is really only an issue with automatics. On the other hand, my aunt’s '02 Taurus has an open-door light lit on the dash all the time, so relying on valid inputs for something as important as doing what a car is meant to do might prove somewhat risky. ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [April 2, 2016, 2:15am UTC](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477/115 "2016-04-02T02:15:12Z")
> [@eschereal](#): > > There is a seatbelt sensor in most cars, and there are door sensors in most cars, so a simple switch that prevents the car from moving itself forward if both of those switches are open. Automatics cannot be push-started nearly as easily as a manual, and creep is really only an issue with automatics. > > On the other hand, my aunt’s '02 Taurus has an open-door light lit on the dash all the time, so relying on valid inputs for something as important as doing what a car is meant to do might prove somewhat risky. As was the ignition key introduced back in the 1900s. It just depends on what we choose to consider necessary by today’s standard. [Previous page](https://boards.straightdope.com/t/auto-transmission-drives-without-foot-on-the-pedal-why-is-this-still-an-issue/750477.md?page=5)