John J. Morris
Executive Vice President, Chief Operating Officer at Waste Management
Thanks, Jim, and good morning. We're more than pleased with the strong operational performance our team achieved in 2023, showing continuous improvement throughout the year, with standout results in the fourth quarter. During this period, operating expenses as a percentage of revenue improved 240 basis points year-over-year, landing at 60.3% and marking our second best quarterly performance ever. This improvement was primarily fueled by our collection and disposal business, benefiting from the robust operating leverage of our strategic cost optimization.
Our proactive measures to accelerate and improve cost efficiency include leveraging technology to manage labor, managing repair and maintenance costs, and optimizing our overall cost structure. These initiatives led to a substantial improvement in WM's cost to serve metrics, bringing estimated unit cost inflation to low-single-digits by the fourth quarter. When combined with solid results from our pricing initiatives, we greatly enhanced overall margins.
Our strong second-half performance translated into full-year operating expenses as a percentage of revenue of 61.7%, an improvement of 70 basis points. That momentum has carried into 2024 and is evident in our January results even as we face severe weather in some areas we serve.
Two of the key cost categories driving our operating improvements are labor and repair and maintenance. On the labor front, this begins with our persistent focus on reducing turnover. In the fourth quarter, we achieved a noteworthy milestone as driver turnover reached its lowest point at 18.4%, showing improvement as the year progressed. Additionally, our strategic automation initiatives are yielding positive results in the collection -- in collection efficiency, with all three lines of business improving meaningfully in the fourth quarter compared to last year. The results of our technology and automation investments gained traction in the latter part of 2023, leading to significant strides in labor cost management. We expect this to continue into 2024 as we broaden the deployment of our tools across additional sites.
Turning to repair and maintenance. With a full allotment [Phonetic] of trucks received in 2023, we successfully removed over 1,000 excess assets from our operation, improved the age of our routed fleet, and reduced truck rental utilization by nearly 60% since the beginning of 2023. Throughout 2023, our emphasis remained on streamlining maintenance processes, which has resulted in enhanced technician productivity, reduced overtime expenses and diminished reliance on external repair services. This has paid off in the form of lower repair and maintenance costs in both dollars and as a percentage of revenue compared to 2022. We accomplished all this with an unwavering commitment to safety and by enhancing the quality of our fleet. We're proud of the strides we made throughout 2023 and look forward to sustained progress.
Another core element of the equation that fueled our strong financial results is disciplined organic revenue growth. Growth from price and volume in the collection and disposal business totaled 6.3% for the year, which outpaced our expectations. Our pricing programs continue to be focused on striking the right balance between maximizing customer lifetime value and increasing price to recover higher costs. Our full-year churn rates remain at the lower end of historical range at about 9%, and the year-over-year improvement underscores our consistent delivery of quality service to our customers.
Looking ahead to 2024, we anticipate sustained momentum in our disciplined pricing programs to result in core price between 6.0% and 6.5% and yield approaching 5%. We remain committed to maximizing customer lifetime value, while securing pricing that exceeds our cost inflation. We have seen that spread improve as 2023 progressed and we are confident that our teams are poised to deliver another successful year ahead.
Turning to volumes. Our fourth quarter collection and disposal volume grew by 1.9% on a workday adjusted basis. Growth was primarily driven by MSW landfill and commercial collection, two bellwethers for demand of our services. Overall growth in landfill volumes was somewhat muted due to the elevated volumes from the Hurricane Ian cleanup in 2022. Similar to recent quarters, residential collection volumes declined modestly due to our intentional shedding of low margin contracts, as we work to ensure that we achieve acceptable returns for all parts of our business. You can see the benefits of this focus, because while our residential collection volumes decline, total revenue and earnings in this line of business both improved. This is a winning equation and we'll continue to execute on this strategy in the year ahead.
Organic revenue growth in all collection lines of business remains positive and operating EBITDA continues to grow. In the fourth quarter, new business grew and net services increases remain firmly positive, reflecting our quality of service and focused differentiation. Looking ahead to 2024, our guidance anticipates collection and disposal volume approaching 1%, mirroring the performance achieved in 2023.
Finally, I want to convey my appreciation to our frontline teams for their unwavering commitment to delivering safe and reliable service to our customers and communities on a daily basis. It's their efforts that made 2023 successful and laid the groundwork for growth in the years ahead.
I will now turn the call over to Devina to discuss our 2023 financial results and 2024 financial outlook in greater detail.