The "gas only" mental model dramatically understates road trip costs. The IRS standard mileage rate (67 cents per mile in 2024) bundles gas, oil, tires, maintenance, depreciation, insurance, and registration — use it for the wear-and-tear line item. Then add tolls, hotels, meals, and the dollar value of driving time.
The formula
Total = (Distance × $0.67) + Tolls + (Hotel × nights) + (Meals × days × travelers) + (Hours × hourly value)
Note: hotel nights = driving days − 1 (last day you arrive home). Meals cover all travelers for all days.
When driving actually wins
Three scenarios favor driving: (1) Multiple travelers — driving cost scales sub-linearly with passengers; flying scales linearly. A family of 5 driving 1,000 miles often beats 5 plane tickets. (2) Lots of gear — ski trips, camping, moving. Baggage fees add up. (3) Vehicle needed at destination — if you would rent a car anyway, driving saves the rental. For solo trips over 500 miles, flying usually wins.