View Single Post
Old 02-04-2006, 05:15 PM
octothorpe octothorpe is offline
Join Date: Aug 2001
Location: Lost Wages, NV
Posts: 229
OK, i'm not going to say that this is a definitive answer by any means, but the non-obvious logic to the 9/10 (or any decimal portion for that matter) cent may have more to do with ensuring accuracy than the psycological effect it may have on the consumer's perception of true price.

To the best of my knowledge, the various state's 'weights and measures' departments (usually a subdepartment of the Agriculture Department) are responsible for ensuring that the consumer isn't defrauded at the pumps. Fuel pumps are supposed to be certified for accuracy annually. This used to be done by dispensing fuel into 'certified' vessels and comparing dispensed fuel to the indication on the pump. Back when i was pumping gas for spending money, the weights and measures people would come by once a year with 2 five-gallon containers and dispense 10 gallons from each pump. If the posted price was 59.9/gal (did i mention how long ago this was?), the the pump better read $5.99 and 10 gallons. If it did, they'd slap a sticker on the pump and be on their merry way. If not, they'd shut down the pump until it was fixed. After the tests, the fuel was poured back into the main storage tanks and a receipt was provided to the operator to make his books balance.

I still occasionally stop at 10 gallons when i'm filling up just to see if the pump's accurate (old habits...).