The correlation between diesel prices and truckload rates is a topic of interest in the freight industry. The average retail price of diesel, which is the primary fuel source for Class 8 trucks, has increased by over 41% since March 2. This rise in fuel costs has had an impact on truckload rates, with the average spot rate for dry van truckloads increasing by 7.5% over the same period.
It is important to note that the correlation between fuel prices and truckload rates is not always straightforward. While there is a positive correlation of 0.7 between diesel prices and truckload rates, indicating that they move together fairly well, this relationship can be influenced by various factors. In March 2022, for example, the correlation was inverted at -0.8, meaning that the two moved in opposite directions at nearly the same rate.
Fuel costs account for approximately 25% of the total operating cost of a truck, although this figure can fluctuate as costs shift. According to the American Transportation Research Institute (ATRI), fuel costs fell from 28% to 21% of total operating costs between 2022 and 2024. Despite these fluctuations, fuel remains a significant portion of operating costs for carriers.
When fuel prices rise sharply, their influence on trucking costs also increases. In the spot market, where rates are typically quoted as all-inclusive totals with no component breakouts, short-term fuel price changes do not directly affect contract rates. Instead, a portion of fuel costs is separated out as a variable surcharge tied to the average price of diesel.
The truckload market experienced a collapse in 2022, with demand falling rapidly as shippers realized they had over-ordered and freight consumption declined. At the same time, truckload capacity had expanded significantly over the prior two years, leading to an imbalance between supply and demand.
Despite the challenges faced by carriers during this period, the current market environment is different. Truckload service values are rising, and carriers are better positioned to pass along higher costs in the spot market. However, it is important to note that a cost increase does not automatically translate into a price increase, as market dynamics play a significant role in determining rates.
In conclusion, the relationship between diesel prices and truckload rates is complex and influenced by various factors. While there is a correlation between the two, it is important to consider the broader market context when analyzing their impact on freight costs.

