The U.S. average price of regular gasoline reached $4.319 per gallon for the week measured September 14, up 16.2 cents from one week earlier and $1.151 from a year earlier, according to the Energy Information Administration's September 15 fuel update.
On-highway diesel rose even faster, reaching $6.285 per gallon. That was an increase of 31.8 cents in one week and $2.546 from the comparable week of 2025.
The figures are weekly national averages that include taxes. They do not predict what an individual dealership will pay, establish a transportation surcharge or prove that shoppers will change powertrain preferences.
Why it matters
Fuel prices touch dealership operations in two different ways. Gasoline changes the ownership-cost conversation for shoppers, while diesel is a direct input for many vehicle carriers, parts deliveries, towing operations and commercial customers. A higher national average can therefore affect both customer questions and store expenses even when retail demand remains stable.
Cox Automotive identified diesel above $6 as the week's main auto-market issue and said transportation costs deserved close attention. That observation is industry context, not proof that carriers will impose a particular surcharge or that vehicle prices will increase by a predictable amount.
The immediate dealer task is measurement. Stores should separate actual fuel, delivery and transportation expenses from broad headlines, then watch whether lead mix, trade activity or model-level turn changes in their own markets.
Regional averages remain materially different
EIA put the Gulf Coast gasoline average at $3.852 per gallon, compared with $5.467 on the West Coast. The Midwest average was $4.091 and the Lower Atlantic average was $4.041.
Diesel averaged $6.027 on the Gulf Coast, $6.096 in the Lower Atlantic and $7.250 on the West Coast. The Lower Atlantic posted the largest regional weekly diesel increase in EIA's table, rising 49.1 cents.
Those differences make national figures unsuitable for quoting a customer's fuel expense or setting a storewide logistics assumption. Dealers should use local invoices, carrier notices and the customer's actual driving pattern.
Use ownership cost without turning it into a sales claim
Sales and BDC teams should expect more questions about fuel economy, hybrids, EVs and diesel ownership. Product comparisons should use the EPA rating for the specific configuration and a customer's stated mileage and use case—not a promise about savings or future fuel prices.
Used-vehicle and acquisition teams can monitor search activity, appraisal close rates and turn by powertrain. A national fuel-price increase alone is not evidence that a gas-powered truck, hybrid or EV should receive a different bid.
F&I teams can include fuel in a transparent household-budget discussion, but the published pump averages do not change lender underwriting, program eligibility or the customer's verified ability to pay.
Track operating exposure before changing policy
Dealership groups can quantify weekly spend for fuel, dealer trades, home delivery, mobile service, towing and vehicle transport. Carrier surcharges should be documented against contracts or invoices rather than assumed from the EIA average.
Managers should also distinguish a fuel-driven expense increase from changes in route volume, delivery distance or operating efficiency. That prevents a higher total bill from being attributed entirely to price when the store's activity also changed.
AI-assisted reporting disclosure
This article was researched and generated with AI-assisted systems using the references listed below. Dealership Tech Report applies automated accuracy and risk checks, but errors or later changes remain possible. Verify time-sensitive market information with the cited sources before acting.
EIA's figures are weekly national and regional averages that include taxes. They are not a local pump-price quote, forecast, carrier rate, dealership expense index or measure of vehicle demand. Week-to-week changes can reverse, and observed fuel prices do not establish why an individual customer's purchase decision or a dealership's operating cost changed.
Cited references
- U.S. Energy Information Administration — Gasoline and Diesel Fuel Update — Federal weekly price release; published Sep. 15, 2026 for prices measured Sep. 14
- Cox Automotive — Auto Market Weekly Summary — Commercial industry commentary; published Sep. 14, 2026