The Bureau of Labor Statistics’ gasoline index rose 34.2 percent in the 12 months ended in September. Its motor vehicle insurance index fell 5.0 percent over the same stretch, the largest decline of any category on the agency’s chart of the September figures. Used cars and trucks slipped 1.5 percent, and new vehicles rose 0.6 percent while prices overall climbed 3.7 percent.
Put those numbers side by side and the September Consumer Price Index describes a car budget that has split in two. The fixed costs of keeping a car in the driveway, meaning the purchase price, the used-car value and the insurance bill, have stalled or turned down. The costs of each mile driven, fuel first and shop labor second, have jumped. For anyone setting a household budget, shopping for a car or deciding whether to keep an old one, the numbers that deserve attention this fall are different from the ones that mattered a year ago.
September’s gasoline numbers, in index points and in dollars
BLS published the September report on October 14. The gasoline index rose 9.1 percent in September alone on a seasonally adjusted basis, and the agency said that single item accounted for more than half of the month’s overall increase. Energy prices were up 20.4 percent from a year earlier. Strip out food and energy and the index rose 2.6 percent. A gap that wide is the signature of a fuel shock rather than broad inflation.
The Energy Information Administration’s pump survey puts dollars on it. Regular gasoline averaged $4.355 a gallon in September, against $3.166 in September 2025, an increase of $1.19. In the week of October 12, regular averaged $4.331, $1.27 above the same week last year, and on-highway diesel averaged $6.179, up $2.514. Regular is still below its June 2022 monthly average of $4.929. Diesel is not: the weekly figure of $6.529 on September 21 was a record.
The climb did not build slowly. Regular averaged $2.908 in February and $3.638 in March, and the CPI gasoline index jumped 21.2 percent, seasonally adjusted, in March by itself. The EIA’s October Short-Term Energy Outlook ties the price to constrained oil flows from the Middle East since the onset of hostilities there, with tankers moving through the Strait of Hormuz in convoys and attacks on Saudi Arabia’s East-West pipeline adding to the risk. The agency now expects Brent crude to average $105 a barrel in the fourth quarter, $14 more than it forecast a month earlier.
For a car rated at 25 mpg and driven 12,000 miles a year, the $1.27 increase works out to about $610 a year in extra fuel. That is The Auto Wire’s arithmetic, using the EIA weekly price change and round-number assumptions for mileage and economy.
Why the adjusted September gas number ran higher than the pump sign
Before seasonal adjustment, BLS said gasoline rose 6.5 percent in September. After adjustment, the figure was 9.1 percent. The difference comes from the fuel calendar. The EPA’s summer limits on gasoline vapor pressure apply from June 1 to September 15. After that, stations switch to winter-grade fuel, which can contain more of the volatile, inexpensive blending components that summer rules restrict, and pump prices normally ease in the fall. BLS’s seasonal factors expect that dip. When prices rise in September instead, the adjusted number exaggerates the move relative to what a driver saw at the station.
The agency’s technical note says unadjusted data are of primary interest to consumers concerned with the prices they actually pay. The 6.5 percent figure is the one that reached your card. The 9.1 percent figure tells you how unusual it was for September.
Premium buyers saw a smaller percentage and a larger bill
BLS breaks the gasoline index out by grade, and the detailed table shows regular up 35.2 percent over the year, midgrade up 31.1 percent and premium up 28.9 percent. On paper, the premium buyer got the mildest increase.
The EIA’s dollar figures say otherwise. Premium averaged $5.357 in September, up $1.255 from $4.102 a year earlier. Regular rose $1.189. The gap between the two grades widened from about 94 cents to almost exactly $1.00. Premium shows a smaller percentage only because it started from a higher price. A driver whose owner’s manual lists premium as required, as opposed to recommended, paid more extra per gallon than anyone filling up with regular.
Diesel inventories are the tightest part of the fuel market
Diesel averaged $6.29 in September, according to the EIA outlook, and the agency described the diesel market as extremely tight. East Coast distillate inventories, which include diesel and heating oil, were 32 percent below their five-year seasonal average in September. The EIA expects them to stay about 20 percent below the 2021 to 2025 average through the winter, and it said refiners chasing diesel demand are adding pressure on crude prices too.
That matters to more people than truckers. A heavy-duty diesel pickup averaging 15 mpg over 12,000 miles burns 800 gallons a year, so the $2.514 year-over-year increase adds roughly $2,011 to the fuel bill. Diesel also hauls the parts, tires and new cars that end up at dealers and repair shops. Our earlier look at a possible ban on diesel exports explains why squeezing diesel supply can push gasoline prices up as well.
Car insurance has fallen for seven straight months
The insurance decline comes after a steep run-up. From September 2023 to September 2024, the BLS motor vehicle insurance index rose 16.3 percent, by The Auto Wire’s calculation from the published index levels. The next 12 months added another 3.1 percent. The index peaked in February 2026, and in unadjusted terms it has fallen every month since, for a total drop of 5.7 percent through September.
Even after that slide, the index sits 14.0 percent above its September 2023 level, so the relief is partial. It also may be slowing. On a seasonally adjusted basis, insurance rose 0.1 percent in September after falling 0.3 percent in July and 0.8 percent in August. And the national average does not describe every renewal: in August, The Auto Wire covered an industry projection that 32 states would finish 2026 with higher premiums than they started with.
Allstate’s numbers line up with the BLS trend. Allstate’s second-quarter report showed its average Allstate-brand auto premium falling from $850 to $819 while its new auto applications rose 8.8 percent. The timing of the CPI decline, which began the same month gasoline spiked, invites a theory that drivers cut their miles and filed fewer claims. The CPI data cannot show that, and the BLS release does not address it.
BLS weights each item by its share of consumer spending, and as of August it gave gasoline a relative importance of 3.853 percent of the CPI basket and motor vehicle insurance 2.531 percent. By the agency’s own weighting, urban households now spend about half again as much on gasoline as they do on car insurance.
Repair shops are raising prices faster than parts stores
The motor vehicle maintenance and repair index rose 5.8 percent over the year. Inside it, maintenance and servicing rose 7.8 percent, body work 6.0 percent and repair 3.5 percent. The retail side barely moved: tires rose 0.2 percent and motor vehicle parts and equipment 0.8 percent.
The CPI does not separate labor from parts inside the service categories, but the spread between those lines points to the shop rather than the box on the shelf. A tire bought at retail cost about the same as a year ago. Having a technician do the routine work cost nearly 8 percent more. For owners stretching an older car another year because used prices look soft and insurance is easing, that service inflation is the cost that keeps compounding. State registration and license fees rose 3.3 percent, and car and truck rental, the bill many people pay while their car is in the shop, rose 9.1 percent.
What September’s prices mean for a car purchase
Vehicle prices are not the problem this year. Used cars and trucks are down 1.5 percent from September 2025, new vehicles are up 0.6 percent, and the index for leased cars and trucks is down 0.1 percent. What has changed is the value of fuel economy. Electricity prices rose 4.4 percent over the year while gasoline rose 34.2 percent, so the per-mile advantage of a plug-in widened in the same 12 months. AAA’s 2026 ownership-cost study, which found hybrids cheapest in every class it compared. Higher fuel prices strengthen that result.
A buyer should not price a six-year loan around September’s pump, though. The EIA forecasts regular gasoline will average $3.56 a gallon in 2027 and diesel about $4.50, with Brent falling to $84 as Middle East exports recover. The efficiency math changes with it. A 40 mpg car driven 12,000 miles uses 300 gallons a year, 180 fewer than a 25 mpg car. At September’s $4.355 average, those 180 gallons cost about $784. At the EIA’s 2027 forecast, they cost about $641. The efficient car still saves real money at the lower price, but the savings shrink by roughly $140 a year, and that difference belongs in any calculation of how much extra to pay for a hybrid or EV.
Dates and figures to watch through the winter
BLS publishes the October CPI on November 10, and the EIA releases its next outlook the same day. The October outlook counted the 40 million barrels of Strategic Petroleum Reserve crude exchanges announced September 29 but not the G7 announcement of October 2, so the November forecast will be the first to reflect it. Pump prices have already eased a little: regular fell from $4.465 in the week of September 28 to $4.331 in the week of October 12.
On the ownership side, watch whether September’s small seasonally adjusted rise in insurance becomes a trend at renewal time, and whether service prices keep running near 8 percent while parts stay flat. Diesel owners in the Northeast have the least room for comfort, with the EIA expecting distillate stocks there to stay well below normal until the second half of next year.
If you were buying a car this fall, would you pay more up front for a hybrid or EV to get away from $4 gas, or take the EIA at its word on $3.56 gas next year and buy the cheaper gas model?