When at a risk of a collision, the E-pretensioner system, working with the collision mitigation braking system (CMBS), retracts the driver's and front passenger's seat belt several times slightly to provide a tactile warming to the driver. And when a collision is imminent, the E-pretensioner system retracts the seat belt tightly to help reduce injury from the impact. The E-pretensioner system also works when the driver brakes hard and the brake assist system is turned on.