One of the most unpredictable things for any planning is the human factor. The behaviour of the driver, such as speeding, taking breaks, or deviating from the route, can influence the schedule. Moreover, if a driver is experiencing a health issue, they may not be able to drive safely, which can delay or disrupt the delivery process and put the driver at risk of car accidents. Accidents also cause delays, damage to the goods being delivered, and even result in injuries to the driver. This leads to additional costs for the business, and can negatively impact customer satisfaction.