Insurance — Commercial automobile liability — Coverage — Insurer of truck that collided with two vehicles, one immediately after the other, when driver crossed the center line sought declaration of its obligations under two insurance policies issued to driver’s employer and owner of the truck and policy issued to company which listed the truck as covered auto — District court did not err in concluding that coverage existed under policy that specifically listed the truck but not the owner’s policies where dispositive question is whether an enforceable lease granting exclusive use rights existed, and there is no genuine issue of material fact that such lease existed because defendants failed to produce any evidence that nonowner company had “exclusive use rights” at time of the accident, an essential element of defendants’ case on which they would bear the burden of proof at trial — Defendants needed to prove content of lease, that there was a contractual relationship giving exclusive use rights at the time of the accident, and the best evidence of content of lease is writing itself — Even if an exception to best evidence rule applied, there was not enough evidence of writing’s contents at summary judgment stage to conclude an enforceable lease granting exclusive use rights existed — Reconsideration — District court did not abuse discretion in denying motion for reconsideration of its summary judgment order where motion was based on evidence purporting to establish that lease granted insurer exclusive use rights, but evidence was available and could have been presented at summary judgment stage — Number of accidents — Under policies at issue and Georgia law, the multi-auto collision in instant case was a single accident — Under Georgia law, cause theory applies to determine number of accidents — Applying the cause theory, the chain of events constituted a single accident where driver did not regain control of truck as he crossed the center line and collided with the two vehicles and evidence indicates that truck moved into the southbound lane and, as an uninterrupted consequence of that move, hit two vehicles