MACK, Colo (KKCO) It happened around 4:30am Sunday morning. Colorado State Patrol responded to an accident involving a pick-up truck towing another pick-up truck on I-70 near the Mack exit. The driver lost control of his truck, causing the towed truck to swing around, knocking the driver's truck on its side. Once the towed pick up truck broke loose, it traveled about 550 feet before stopping near a wire fence. I-70 west bound was shut down while the accident was cleared. Authorities believe speed and poor tires are factors in the accident.