There are several issues at work here when it comes to Gasbuddy:
Regular prices can be fairly reliable, but:
During times of rapidly changing prices, even if people are reporting prices honestly and reliably, it may take a number of accurate reports before GB updates the price. That’s because GB has what they call a “reasonableness” check-any report that significantly differs from the last displayed price will require a number of additional reports at that new price before the site finally accepts it.
I often have to report something half a dozen times or more to finally get it to stick-in some cases I’ve reported them dozens of times (until I run out of time after reaching the current time), sometimes to no avail. But enough reports will ensure the price gets correctly updated, sooner or later.
That’s for regular.
For plus or premium however (and likely diesel), caveat emptor most certainly applies:
Most stations don’t report those prices on their marquees, so you have to drive up to a pump to see what they are. The vast majority of (accurate) reports however are by people who are driving by, so only regular tends to get accurate reports.
But, John, you say, most reports on GB DO show the non-regular prices! Indeed, they do, most of the time.
“So why does this Exxon over there say 4.41 reg, 3.69 plus, and 4.05 prem today?” you might ask. (from an actual report I saw today, Jacksonville FL)
Gasbuddy, in their infinite wisdom, has this points program, you see. The more prices you report, the more points you get, and thus a greater chance of winning one of their lotteries to get free gas cards, or a blow up doll, or something. The quaint notion that people would be willing to report prices for the greater good without some preschool level stick-and-carrot nonsense is apparently utterly beyond their ken.
So what will happen in such a scheme? If nobody reported the non-regular prices, they’ll eventually go blank, after 72 hours iirc. But somebody is reporting them, obviously.
Obviously.
If you click and see who was the last person to have reported for a given station, you’ll almost invariably see that they live several states away. How noble it is then to have all of these selfless souls constantly scouring the country reporting hundreds of prices per hour-whatever would we all do without their tireless efforts?
Of course, they in fact haven’t moved their fat asses from their devices all day long (except to go get a beer from the fridge periodically). They’re simply clicking on a given station and simply parroting the most recently accepted GB report, no matter how outdated/inaccurate it may be.
The local regular prices will eventually get corrected if sufficient local residents chime in. But since so few report the other grades, these stay at home points whores (as I like to call them) will tend to win the battle, at least for a number of days (until either they finally go blank after nobody reported anything for 3+ days, or the locals somehow manage to outreport them).
But, certainly, if there is a reasonableness check for regular, there MUST be one to check for the gaps between grades! After all, NO station anywhere will have +/premium cheaper than regular, would they?
You might think that would be an awesome notion that undoubtedly got implemented eons ago, but you would be wrong. The GB site has no such check, so the other grades can be pretty much anything. Oh, but they do have their own checks. In the example above, it is likely the actual + price is at least a dollar above the reported one. Which means, thanks to the in-grade check that it would likely require HUNDREDS of accurate reports to override the reported one now. That means that no prices would need to reported before the time limit cancels them out, so that then a local soul can finally get the right price in.
But our stay-at-home agoraphobics definitely keep themselves busy in any event. All this means that Gasbuddy during a period of wild swings in prices is pretty much worthless for those who use non-reg grades. For a local (I myself require premium) you can get to know what the typical intervals between grades are for a given station or chain, add that on to the reported regular price, and off you go. But on vacations it is often a crapshoot even when prices are stable.
HTH.