11. Commitments and Contingencies As of December 31, 2011, we had approximately $20.3 million of obligations remaining under operating lease arrangements related to terminal facilities. Future minimum lease payments under noncancelable operating leases (with initial or remaining lease terms in excess of one year) as of December 31, 2011, are approximately $20.3 million, with payment streams as follows (in millions): 2012 - $8.0; 2013 - $5.0; 2014 - $3.2; 2015 - $2.3, 2016 - $1.3, and 2017 and thereafter - $0.5. Total rent expense was $24.8 million in 2011, $21.8 million in 2010, and $19.4 million in 2009. At December 31, 2011, we had outstanding commitments to acquire approximately $308 million of revenue equipment and facilities in 2012. During 2011, we issued financial standby letters of credit as a guarantee of our performance under certain operating agreements and self-insurance arrangements. If we default on our commitments under the agreements or other arrangements, we are required to perform under these guarantees. The undiscounted maximum amount of our obligation to make future payments in the event of defaults is approximately $8.5 million. We are a defendant in certain class-action allegations in which the plaintiffs are current and former California-based drivers who allege claims for unpaid wages, failure to provide meal and rest periods, and other items. Further proceedings have been stayed in these matters pending the California Supreme Court s decision in a case unrelated to ours involving similar issues. We cannot reasonably estimate at this time the possible loss or range of loss, if any, that may arise from these lawsuits. We are involved in certain other claims and pending litigation arising from the normal conduct of business. Based on the present knowledge of the facts and, in certain cases, opinions of outside counsel, we believe the resolution of these claims and pending litigation will not have a material adverse effect on our financial condition, our results of operations or our liquidity