We continue to diversify our business model with the goal of achieving a balanced portfolio of revenues comprised of One-Way Truckload (which includes the short-haul Regional, medium-to-long-haul Van and Expedited fleets), Specialized Services and VAS. Our Specialized Services unit, primarily Dedicated, ended the quarter with 3,495 trucks (or 48% of our total fleet).
The driver recruiting and retention market remained challenging in second quarter 2012 and was similar to first quarter 2012. Driver pay increased 1.5 cents per mile year-over-year as we made certain pay adjustments over the last year to attract and retain drivers for specific fleets. While historically higher national unemployment rates have aided our driver recruiting and retention efforts, we believe that an improved freight market, extended government unemployment benefit programs, a reduction in available truck driving school graduates and changing industry safety regulations tightened driver supply. While we are not immune to fluctuations in the driver market, we continue to believe we are in a better position in the current market than many competitors because over 70% of our driving jobs are in more attractive, shorter-haul Regional and Dedicated fleet operations that enable us to return these drivers to their homes on a more frequent and consistent basis.
Gains on sales of assets were $5.7 million in second quarter 2012 compared to $5.6 million in second quarter 2011 and $4.7 million in first quarter 2012. The market for the sale of used trucks and trailers remains strong. Gains on sales are reflected as a reduction of Other Operating Expenses in our income statement.
We continue to buy new trucks to replace older trucks we sell or trade. We continue to invest in environmentally friendly equipment solutions such as more aerodynamic truck features, idle reduction systems, tire inflation systems and trailer skirts which improve the mile per gallon efficiency of our fleet. Over the last year, we reduced our annual carbon footprint by almost 98,000 tons. Our net capital expenditures in second quarter 2012 were $39 million which puts year-to-date net capital expenditures for 2012 at $122 million. We expect our net capital expenditures for the full year 2012 to be in a range of $180 million to $210 million. The average age of our truck fleet as of June 30, 2012 was 2.3 years, and we expect to further reduce our average truck age to approximately 2.1 years as of December 31, 2012. We remain committed to the ongoing investment required to maintain a best-in-class fleet while focusing on the lowest operating cost model for our customers.