Adam N. Satterfield
Senior Vice President of Finance, Chief Financial Officer & Assistant Secretary at Old Dominion Freight Line
Thank you, Greg, and good morning. Old Dominion's revenue for the first quarter of 2022 increased 32.9% to a company record of $1.5 billion. While our operating ratio improved 320 basis points to 72.9%. The combination of these factors resulted in a 52.9% increase in earnings per diluted share to $2.60 for the quarter. Our revenue per day increased 30.8% as the first quarter of this year included one extra work day. This growth was balanced between increases in our volumes and yield, both of which continue to be supported by a favorable domestic economy.
We continue to win a significant amount of market share as demand for our superior service and available network capacity to remain consistently strong during the quarter. As a result, the year-over-year growth in our revenue and volumes continued to trend above our longer-term averages. LTL tons per day increased 12% and our LTL revenue per hundredweight increased 17.4%. While changes in our freight mix contributed to the increases in this yield metric, the 10% increase in our LTL revenue per hundredweight, excluding fuel surcharges, reflects the success of our long-term pricing strategy.
Our consistent strategy is designed to offset cost inflation, while also supporting further investments in capacity by focusing on the individual profitability of each customer account. On a sequential basis, revenue per day for the first quarter increased 1.2% as compared to the fourth quarter of 2021. With LTL tons per day decreasing 1.4% and LTL shipments per day decreasing 2.2%. Our revenue per day performance during the first quarter, both with and without fuel surcharges, exceeded our 10-year average sequential trends, although our volumes were below our 10-year trends. It is important to remember, however, that our 10-year average trends include the doubling of our market share.
As a result, there may be quarterly periods where sequential performance may be below our 10-year trends despite solid year-over-year performance. The first quarter is a good example as we believe we won a significant amount of market share and produced solid profitable growth as a result. The monthly sequential changes in LTL tons per day during the first quarter were as follows: January decreased 5.8% as compared with December, February increased 5.1% versus January, and March increased 3.6% as compared to February.
The 10-year average change for the respective months are an increase of 1.6% in January, an increase of 1.7% in February and an increase of 5.6% in March. While there are still a few work days that remain in April, our revenue growth continues to be very strong and reflects the favorable demand environment described earlier by Greg. Our month-to-date revenue per day has increased by approximately 28% when compared to April of 2021. We will provide the actual revenue-related details for April in our first quarter Form 10-Q. Our first quarter operating ratio improved to 72.9%, with improvements in both our direct operating costs and overhead cost as a percent of revenue.
Within our direct operating costs, improvement in our salaries, wages and benefit costs as a percent of revenue effectively offset the increase in expenses for both our operating supplies and purchase transportation. The increase in operating supplies and expenses as a percent of revenue was primarily due to the increase in the cost of diesel fuel and other petroleum-based products. We improved overhead cost as a percent of revenue during the first quarter, primarily by leveraging our revenue growth and controlling discretionary spending.
As mentioned on our fourth quarter call, we expect our core inflation, excluding fuel, to be between 4.5% to 5% for the year, with higher inflation in the first half of the year that is expected to moderate in the back half. We believe our fuel surcharge program is effectively offsetting the increased cost of our fuel and our yield management strategy is effectively offsetting cost increases in other areas. As we continue to experience cost increases related to our real estate network as well as with our equipment, parts and repairs, it will be critical to maintain our focus on productivity while continuing to control discretionary spending to minimize the overall effect on our cost per shipment.
Old Dominion's cash flow from operations totaled $388.7 million for the first quarter and capital expenditures were $93.7 million. We currently anticipate our capital expenditures to be approximately $825 million this year, which includes $300 million to expand the capacity of our service center network. We utilized $438.4 million of cash for our share repurchase program and paid $34.2 million in dividends during the first quarter.
The total amount for share repurchases includes a $400 million accelerated share repurchase agreement that was executed during the first quarter. Our effective tax rate was 26.0% for the first quarter of 2022 and 2021. We currently expect our annual effective tax rate to be 26.0% for the second quarter 2022. This concludes our prepared remarks this morning.
Operator, we'll be happy to open the floor for questions at this time.