Douglas Chambers
Analyst · JPMorgan
Good morning. Let me touch briefly on postpaid connections results during the fourth quarter, shown on Slide 8. Postpaid handset gross additions decreased due to lower switching activity and decreased store traffic due primarily to the impacts of COVID-19. This decrease was partially mitigated by increased demand for connected devices. Total smartphone connections increased by 47,000 over the course of the past 12 months. That helps to drive more service revenue given that smartphone ARPU is about $21 higher than feature phone ARPU.
As mentioned, we saw connected device gross additions increased by 12,000 year-over-year. This was driven by gross additions of hotspots, routers and fixed wireless devices as a result of an increase in demand by customers seeking wireless products to meet their need for remote connectivity due to the impacts of COVID-19. During Q4, we saw an average year-over-year decline in store traffic of around 30% related to the impacts of COVID 19. The decrease in store traffic had a negative impact on gross additions although connected device activity remains stronger than the prior year.
Next, I want to comment on the postpaid churn rate, shown on Slide 9. Currently, as you would expect, churn on both handsets and connected devices is running at low levels. Postpaid handset churn, depicted by the blue bars, was 1.01%, down from 1.11% a year ago. This was due primarily to lower switching activity as customers' shopping behaviors were altered due to the pandemic.
The FCC keep Americans connected pledge ended on June 30, and about 60% of the customers that were on the pledge at June 30 are actively paying. Our churn was not materially impacted by the pledge in the fourth quarter or the full year 2020. Total postpaid churn, combining handsets and connected devices, was 1.21% for the fourth quarter of 2020, also lower than a year ago.
Now let's turn to the financial results on Slide 10. Total operating revenues for the fourth quarter were $1.073 billion, a modest increase year-over-year. Retail service revenues increased by $17 million to $683 million. The increase was primarily due to a higher average revenue per user, which I will discuss in a moment.
Inbound roaming revenue was $33 million. That was a decrease of $9 million year-over-year driven by a decrease in data volume. One of the factors contributing to this data volume decrease is the merger of Sprint and T-Mobile and the migration of Sprint roaming traffic to T-Mobile's network. Other service revenues were $60 million, an increase of $5 million year-over-year, partially due to a 9% increase in tower rental revenues.
Finally, equipment sales revenues increased by $8 million year-over-year due to an increase in average revenue per unit for new smartphones, partially offset by lower accessory sales.
Now a few more comments about postpaid revenue, shown on Slide 11. Average revenue per user or connection was $47.51 for the fourth quarter, up $0.94 or 2% year-over-year. On a per account basis, average revenue grew by $3.88 or 3% year-over-year. The increases were driven by several factors, including increased device protection revenues, an increase in regulatory recovery revenues and having proportionately fewer tablet connections, which on a per unit basis contribute less revenue than smartphones.
Turning to Slide 12. As we continue our multiyear network modernization and 5G rollout, control of our towers remains very important. By owning our towers, we ensure we maintain the operational flexibility to add new equipment and make other changes to our cell sites without incurring additional costs, which is very important particularly when you were going through a technology evolution. While the towers support our network strategy, we also recognize that they are valuable in providing a financing alternative, which we evaluate along with our other financing options. As you can see on the slide, with the assistance of our third-party marketing agreement, we have seen steady growth in our tower rental revenues. Fourth quarter tower rental revenues increased by 9% year-over-year. We will continue to focus on growing revenues from these strategic assets.
Moving to Slide 13. I want to comment on adjusted operating income before depreciation, amortization and accretion and gains and losses. To keep things simple, I'll refer to this measure as adjusted operating income. As shown at the bottom of the slide, adjusted operating income was $178 million, a decrease of 2% year-over-year. As I commented earlier, total operating revenues were $1.073 billion, a 2% increase year-over-year. Total cash expenses were $895 million, increasing $24 million or 3% year-over-year.
Total system operations expense increased year-over-year. Excluding roaming expense, system operations expense increased by 7%, driven partially by costs associated with our network modernization and 5G deployment, including higher maintenance and support costs for network operations, higher cell site rent expense and an increase in cost to decommissioned network assets. Note that total system usage grew by 36% year-over-year.
Roaming expense increased $3 million or 9% year-over-year due to a 68% increase in off-net data usage, partially offset by lower data rates. Cost of equipment sold increased $14 million or 5% year-over-year due primarily to an increase in the average cost per unit for new smartphones, partially offset by a decrease in accessories sales.
Selling, general and administrative expenses decreased $4 million or 1% year-over-year, driven primarily by a decrease in bad debt expense. Bad debt expense decreased $10 million due to lower write-offs driven by fewer non-pay customers as a result of a better credit mix and improved customer payment behavior. Also contributing to the decrease was lower advertising expense due to reduced sponsorship expense from canceled events related to COVID-19.
Turning to Slide 14, and adjusted EBITDA, which starts with adjusted operating income and incorporates the earnings from our equity method investments, along with interest and dividend income. Adjusted EBITDA for the quarter was $222 million, flat year-over-year. Equity and earnings of unconsolidated entities increased by $4 million or 11%.
Now let's turn to Slide 15, where we show our full year financial results. Total operating revenues were $4 billion, a modest increase year-over-year. This was driven by an increase in retail service revenues due to higher average revenue per user, partially offset by a decline in the average postpaid subscriber base. Also contributing to the increase were higher tower rental revenues and miscellaneous other service revenues. These increases were partially offset by decreases in inbound roaming revenues and equipment sales.
Total cash expenses were $3.2 billion a decrease of $29 million year-over-year. This was due primarily to a decrease in selling, general and administrative expenses, driven by decreases in bad debt expense and advertising expense. Also contributing to the decrease was lower cost of equipment sold. Such factors were partially offset by an increase in system operations expense. System operations expense increased by 3% despite a 54% increase in total system usage on our network and a 59% increase in off-network data usage. Adjusted operating income and adjusted EBITDA grew by 5%.
Next, I want to cover our guidance for the full year 2021. For comparison, we're showing our 2020 actual results. Our guidance assumes that COVID-19 does not cause any significant incremental economic consequences that would negatively impact our business. As such, COVID-19 financial impacts, consistent with those experienced in the second half of 2020, have been contemplated in establishing the assumptions used in developing our financial guidance.
For total service revenues, we expect a range of approximately $3.025 billion to $3.125 billion. This reflects our expectation of low single-digit growth in billed revenues and ongoing pressure with respect to inbound roaming revenues as legacy Sprint roaming traffic continues to decline and other carriers take measures to manage their roaming traffic.
We expect adjusted operating income to be within a range of $800 million to $950 million and adjusted EBITDA within a range of $975 million to $1.125 billion. This guidance reflects our estimates for moderate growth in both revenues and cash expenses. Cash expenses are impacted by estimated increases in loss on equipment due to a higher expected transaction volume and bad debts as this expense trends toward pre-pandemic levels.
For capital expenditures, the estimate is in a range of $775 million to $875 million. This reflects our expectation of lower network capital spend. We have provided a breakdown by major category for our 2020 and estimated 2021 capital expenditures. We were able to pull some network spend forward into 2020 from 2021 and completed our VoLTE deployment, which contributed to the decrease in expected 2021 capital expenditures compared to 2020.
I will now turn the call over to Jim Butman. Jim?