You should also note that today's call includes references to free cash flow, adjusted EPS, EIBTDA and adjusted EBITDA, each of which is non-GAAP term. Speaking today for United Rentals is Michael Kneeland, Chief Executive Officer; William Plummer, Chief Financial Officer; and Matt Flannery, Chief Operating Officer. I will now turn the call over to Mr. Kneeland. Mr. Kneeland, you may be gin.
Thanks, Operator. Good morning, everyone, and welcome. With me today is Bill Plummer, our CFO, and Matt Flanner, who became our Chief Operating Officer in April with other members of our senior management team.
We'll take a look at the quarter review and we're going to update you on the RSC integration and give you our thoughts on the balance of the year. And after that, we'll take your questions.The second quarter, as you know, was a transformation for us. It includes one month of our results as a standalone company and two months in combination with RSC. That meant our employees had to manage an incredible amount of change during the quarter and they still turned in some great results despite the attention required by the integration. As we reported last night, we had a 61.3% increase in rental revenue year-over year, a 7.4% increase in rates and a 63.7% increase in rental volume and $418 million of adjusted EBITDA and an adjusted EBITDA margin of 42.1%. That's seven points higher than a year ago and it's a company record for us. Time utilization came in a little softer than we expected in the quarter and it was down by two-tenths of a percentage point year-over-year. That's primarily tied to the deployment of our fleet and we brought $1 billion of fleet into the market and it performed very well for us with the exception of a few regions.