Vehicle experiences steering vibration when at highway speeds (above 65mph). I have brought the vehicle in for service four times and the issue still returned after multiple alignments, rotations, and road force balances. The local service techs are working with Kia, but it has currently been in the shop for 24 days with no resolution. According to the service advisor, tires have been inspected and even swapped with new ones but the problem is still present. I am concerned with the safety of the vehicle because it creates issues with control at high speeds which could result in an accident. Even at low speeds, the rear end fishtails over small bumps creating a temporary loss of control. I am unsure if the two are related. I can provide Kia service order numbers and Kia customer care case number upon request. Multiple other owners have experienced the same concerns and have posted a growing number of instances where the vehicle was purchased back by Kia as a result.