# Gas pumps and pre pay **URL:** \ **Category:** Factual Questions\ **Created:** [September 10, 2011, 3:48am UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791 "2011-09-10T03:48:44Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![obbn](https://avatars.discourse-cdn.com/v4/letter/o/d6d6ee/32.png) [@obbn](https://boards.straightdope.com/u/obbn)\ **Post date:** [September 10, 2011, 3:48am UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/1 "2011-09-10T03:48:44Z")
Hello Again, Something really irritates me and hopefully there is a logical explination. When you pre-pay for gas around here (and you must if you use cash) the pump always comes to a crawl about .50 cents from the full amount. It takes the stupid pump about the same time to pump out that remaining few cents as it did to pump out the first $19.50 (on a $20 purchase). Why is it that when pre-paying the gas pump has to slow down the fill up so far from the total. The obviously have the technology to stop it at a pre-determined number, so why not stop it .10 cents from your total so I don’t have to stand there in the rain waiting for the last .50 cents to pump? It’s very irritating. Is there a reason for this or are the guys behind the counter getting a big laugh? My wife said it is to keep people from over filling the tank, ie: you think your car needs $20, but will only hold $19.50. I don’t buy that because the nozzle will stop when the tank gets to near full by itself. ---
**Author:** ![Full\_Metal\_Lotus](https://avatars.discourse-cdn.com/v4/letter/f/df705f/32.png) [@Full\_Metal\_Lotus](https://boards.straightdope.com/u/Full_Metal_Lotus)\ **Post date:** [September 10, 2011, 4:55am UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/2 "2011-09-10T04:55:26Z")
The pump itself takes a few revolutions to shut down the flow completely. When you pump by free flow the gas nozzle is squeezed to turn on the pump, and released to shut it off, the pump continues its cycling/pumping until the back pressure sensor turns it off, and the excess fuel is returned to the storage tank via a overflow line. When the machine controls it, in a pre pay situation, the only thing is to shut the pump off. If it was running at full pressure, there would be a big chance of dribble, leakage or too much gas coming out of the nozzle. I guess, in simple terms, the pump has to slow down to a crawl to insure that the corredct amount is dispensed accurately and safely. It takes long enough by simple control of the pump that the 50cent margin has to be used. Hope that helps/ ---
**Author:** ![Balthisar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/balthisar/32/2825_2.png) [@Balthisar](https://boards.straightdope.com/u/Balthisar)\ **Post date:** [September 10, 2011, 2:38pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/3 "2011-09-10T14:38:17Z")
If you have to pay cash for some reason, then the quick solution is to tell them you want (e.g.) $80 of gas when you know then tank will only hold $60. Give them $80, fill quickly, collect your change. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [September 10, 2011, 3:56pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/4 "2011-09-10T15:56:06Z")
> [@Balthisar](#): > > If you have to pay cash for some reason, then the quick solution is to tell them you want (e.g.) $80 of gas when you know then tank will only hold $60. Give them $80, fill quickly, collect your change. and watch as you inevitably stop it at $60.01 😉 ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [September 10, 2011, 4:10pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/5 "2011-09-10T16:10:22Z")
Let’s be realistic - I’ve never seen a pump take more than 10 seconds to do the final slow pumping. ---
**Author:** ![Absolute](https://avatars.discourse-cdn.com/v4/letter/a/b2d939/32.png) [@Absolute](https://boards.straightdope.com/u/Absolute)\ **Post date:** [September 10, 2011, 4:26pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/6 "2011-09-10T16:26:48Z")
Just pay with a debit card or credit card. The pump stops immediately when your tank is full. Simple. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [September 10, 2011, 4:29pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/7 "2011-09-10T16:29:09Z")
> [@beowulff](#): > > Let’s be realistic - I’ve never seen a pump take more than 10 seconds to do the final slow pumping. The pumps by me slow down for the last $1, I’m quite sure they take more then ten seconds. The other day I was filling up at a place that didn’t have prepay. It’s the first time in months I’ve had a full tank since I normally just put $20 in at a time so I don’t have to go back in. ---
**Author:** ![obbn](https://avatars.discourse-cdn.com/v4/letter/o/d6d6ee/32.png) [@obbn](https://boards.straightdope.com/u/obbn)\ **Post date:** [September 10, 2011, 6:49pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/8 "2011-09-10T18:49:26Z")
> [@beowulff](#): > > Let’s be realistic - I’ve never seen a pump take more than 10 seconds to do the final slow pumping. You should come down to my local BP station. Last night I timed it. To finish the last .48cents it took 26 seconds. :smack: ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [September 10, 2011, 8:14pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/9 "2011-09-10T20:14:53Z")
don’t fill up in the rain, find a station with a rain canopy, take reading material. ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [September 11, 2011, 1:25pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/10 "2011-09-11T13:25:13Z")
> [@Absolute](#): > > Just pay with a debit card or credit card. The pump stops immediately when your tank is full. Simple. That assumes they take a credit card. Last time I filled my tank in St. Albans, VT (7 miles from the border) they wouldn’t accept a CC unless you could tie it to a US ZIP code.😕 ---
**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\ **Post date:** [September 11, 2011, 3:12pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/11 "2011-09-11T15:12:16Z")
It’s the other way around too, **Hari** - some tanks up here won’t take US credit cards, though there’s no requirement to give the postal code that I know of. I won’t go to a station that doesn’t let me pay at the pump with a credit card. I don’t see why I should ever have to set foot inside a gas station building when all I intend to buy is gasoline. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [September 11, 2011, 9:13pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/12 "2011-09-11T21:13:06Z")
> [@mnemosyne](#): > > I won’t go to a station that doesn’t let me pay at the pump with a credit card. I don’t see why I should ever have to set foot inside a gas station building when all I intend to buy is gasoline. Me too. Any station that assumes I am a thief, and treats me that way, doesn’t get my business. Especially ones that make me come inside and wait in line to leave my credit card, go outside and fill my tank, then come back in and wait in line again to pay. I just drive off and go elsewhere. ---
**Author:** ![Ambivalid](https://avatars.discourse-cdn.com/v4/letter/a/a5b964/32.png) [@Ambivalid](https://boards.straightdope.com/u/Ambivalid)\ **Post date:** [September 11, 2011, 9:30pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/13 "2011-09-11T21:30:35Z")
> [@t-bonham@scc.net](#): > > Me too. Any station that assumes I am a thief, and treats me that way, doesn’t get my business. Especially ones that make me come inside and wait in line to leave my credit card, go outside and fill my tank, then come back in and wait in line again to pay. I just drive off and go elsewhere. I didn’t even know such stations existed. ☹ ---
**Author:** ![JoelUpchurch](https://avatars.discourse-cdn.com/v4/letter/j/f05b48/32.png) [@JoelUpchurch](https://boards.straightdope.com/u/JoelUpchurch)\ **Post date:** [September 11, 2011, 10:57pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/14 "2011-09-11T22:57:10Z")
> [@jamiemcgarry](#): > > I didn’t even know such stations existed. ☹ How about a debit card? I always use and a debit card and never had a problem. I assume if a station didn’t trust people, they would have a camera in the pump and maybe photograph the license plate also. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [September 11, 2011, 11:01pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/15 "2011-09-11T23:01:02Z")
I love where I live. Pump, then pay, the way Og intended. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [September 11, 2011, 11:03pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/16 "2011-09-11T23:03:52Z")
> [@t-bonham@scc.net](#): > > Me too. Any station that assumes I am a thief, and treats me that way, doesn’t get my business. Especially ones that make me come inside and wait in line to leave my credit card, go outside and fill my tank, then come back in and wait in line again to pay. I just drive off and go elsewhere. Is that a common method in the US? I’ve never seen that here in the UK. You either fill first then pay inside (vast majority of filling stations) or pay at the pump with a debit/credit card before filling (rare, mainly big supermarket petrol stations or motorway services). In fact, now I come to think of it, I don’t think I’ve ever seen a petrol station that is _only_ pay-at-pump. Even the ones that offer it still have the option of filling first then paying inside. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [September 11, 2011, 11:13pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/17 "2011-09-11T23:13:30Z")
> [@Colophon](#): > > I don’t think I’ve ever seen a petrol station that is _only_ pay-at-pump. Even the ones that offer it still have the option of filling first then paying inside. I’ve seen some where the store was closed, but the pumps could be operated with a credit card. That’s _only_ pay-at-pump. ---
**Author:** ![FoundWaldo](https://avatars.discourse-cdn.com/v4/letter/f/dfb087/32.png) [@FoundWaldo](https://boards.straightdope.com/u/FoundWaldo)\ **Post date:** [September 11, 2011, 11:23pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/18 "2011-09-11T23:23:44Z")
Using credit cards at gas stations is an extremely common way to test stolen (or fraudulently generated) cards. Try a small transaction at a gas station (which requires no interaction with a human, and gives instant approval or denial), and if it works, you know you have a good card. Then you go make your larger fraudulent transactions elsewhere. Because of this, some gas stations receive an enormous volume of chargebacks. Chargebacks not only cost them money, but can result in their ability to accept credit cards being revoked completely. Requiring the cardholder to enter the billing zip code, which is then checked as part of the authorization, is an easy way to dramatically reduce this type of fraud. It raises the bar for fraudulent activity, and makes a big difference. In some cases, the choice basically boils down to asking for the zip code or not accepting cards at all. Why do people object to this, and why do they think it’s “assuming you’re a thief”? First, if you’re a credit card holder, it’s also protecting you because it prevents someone else from using your card at a gas station. Second, it effectively saves you money because the station isn’t paying so many chargeback fees and will be able to have a lower processing rate. Finally, it takes all of five seconds to enter, so you can’t argue that it’s an inconvenience. So why the objection? I’m completely serious. I just don’t get it. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [September 11, 2011, 11:37pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/19 "2011-09-11T23:37:20Z")
> [@Musicat](#): > > I’ve seen some where the store was closed, but the pumps could be operated with a credit card. That’s _only_ pay-at-pump. OK, yes I’ve seen it as an out-of-hours option, but I don’t think I’ve ever seen one where you couldn’t pay inside if you wanted to during normal business hours. ---
**Author:** ![alphaboi867](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alphaboi867/32/3898_2.png) [@alphaboi867](https://boards.straightdope.com/u/alphaboi867)\ **Post date:** [September 11, 2011, 11:39pm UTC](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791/20 "2011-09-11T23:39:23Z")
> [@Colophon](#): > > Is that a common method in the US? I’ve never seen that here in the UK. You either fill first then pay inside (vast majority of filling stations) or pay at the pump with a debit/credit card before filling (rare, mainly big supermarket petrol stations or motorway services). In fact, now I come to think of it, I don’t think I’ve ever seen a petrol station that is _only_ pay-at-pump. Even the ones that offer it still have the option of filling first then paying inside. It depends on where in the US you are and wether you’re at a chain gas station or a mom & pop operation. I used to work in what was the last gas station in the city to allow customers to pump first and then pay (& even then only during daylight). It was a chain to, the small independant stations were all pre-pay/pay-at-pump only. Drive-offs were a constant problem. Coporate was more concenced (or less unconcerend) so all the cameras faced the front of the store. It was also impossible to see the licence plates from inside; even assuming one of us did nothing besides stare out the window. Not every “drive-off” was “intentional” either. Sometimes people would “accidently” pump more gas than they had money to pay for. :rolleyes: Sometimes they’d want to pay with a credit/debit card afterward and the care would either be expired or just keep getting rejected. Some people even though they could get away with paying with a personal check. When we stopped allowing post-pay sales those problems stopped. We had a few minor problems with customers who just wanted to leave a credit or debit card or ID inside, pump, then come in to pay. Our point-of-sale system was setup to make it impossible for the clerk to open a pump without ringing a sale through the register. Most gas stations (I think) give the clerk, or at least a manager that option. Ours didn’t. [Next page](https://boards.straightdope.com/t/gas-pumps-and-pre-pay/595791.md?page=2)