the car's environment that may cause a collision. Systems can respond to a possible collision situation with multiple actions, such as sounding an alarm, tensing up passengers’ seat belts, closing a sunroof, and raising reclined seats. Crosswind stabilization helps prevent a vehicle from overturning when strong winds hit its side by analyzing the vehicle's yaw rate, steering angle, lateral acceleration, and velocity sensors. This system distributes the wheel load in relation to the velocity and direction of the crosswind. Cruise control can maintain a specific speed pre-determined by the driver. The car will maintain the speed the driver sets until the driver hits the brake pedal, clutch pedal, or disengages the system. Specific cruise control systems can accelerate or decelerate, but require the driver to click a button and notify the car of the goal speed. Electronic stability control (ESC) can reduce the speed of the car and activate individual brakes to prevent understeer and oversteer. Understeer occurs when the car's front wheels do not have enough traction to make the car turn and oversteer occurs when the car turns more than intended, causing the car to spin out. In conjunction with other car safety technologies, such as anti-lock braking and traction control, the ESC can safely help drivers maintain control of the car in unforeseen situations. Emergency driver assistant facilitates emergency counteract measures if the driver falls asleep or does not perform any driving action after a defined length of time. After a specified period of time, if the driver has not interacted with the accelerator, brake, or steering wheel, the car will send audio, visual, and physical signals to the driver. If the driver does not wake up after these signals, the system will stop, safely position the vehicle away from oncoming traffic, and turn on the hazard warning lights. Hill descent control helps drivers maintain a safe speed when driving down a hill or other decline. These systems are typically enacted if the vehicle moves faster than 15 to 20 mph when driving down. When a change in grade is sensed, hill descent control automates the driver's speed to descend down the steep grade safely. This system works by pulsing the braking system and controlling each wheel independently to maintain traction down the descent. Hill-start assist also known as hill-start control or hill holder, helps prevent a vehicle from rolling backward down a hill when starting again