Hill Descent Control - a useful feature that 'new drivers' often forget

The DAC downhill assist system helps control the vehicle's speed when going downhill, contributing to the driver's comfort... but in reality, many new drivers often forget or do not know how to use this feature.

As the name suggests, the DAC (Down Hill Assist Control) system equipped on cars helps control the speed of the car when going downhill, contributing to ensuring safety and limiting the phenomenon of brake failure due to the driver frequently applying the brakes.

Many pickup trucks, SUVs and even sedans are equipped with hill descent control systems.

Previously, DAC was only equipped on some pickup trucks, off-road vehicles... However, currently the DAC downhill support system, also known as HDC (Hill Descent Control), has appeared on many models in the SUV, Crossover segment or even high-end sedans.

How does hill descent control work?

When the vehicle is going downhill and the DAC system is activated, sensors or gyroscopes will work to detect the vehicle's tilt angle. The collected data will be processed through the ECU electronic computer system to control the operation of the clutch, the braking system and the distribution of engine torque to the wheels. From there, the system will automatically adjust the vehicle's speed to match the slope of the slope, helping the driver not need to brake.

Hill Descent Control System On/Off Button on Nissan X-trail

Normally when DAC is working, it will combine with the ABS braking system, traction control system and engine, to adjust the speed on each wheel, to avoid the vehicle slipping when going downhill.

How to use the hill descent control system

In fact, many car users, especially new drivers, do not fully understand the operating mechanism of the downhill assist system, so they are not confident when using it and even forget this feature when driving on steep passes or difficult terrain.

The driver does not need to brake, the speed of the vehicle when going downhill is still controlled.

Having only used a Hyundai Tucson gasoline engine for 2 months, Mr. Duc Hieu in Lam Dong shared: "When I first bought the car, the salesperson explained about this feature. However, in reality, when using the car, I rarely activate the downhill assist system even though I often drive on steep terrain, because I don't feel confident enough to let go of the brake when the car is going downhill."

Many “new drivers” when driving automatic cars on steep mountain passes often have the habit of leaving the car in D mode and frequently applying the brakes to control the speed of the car when going downhill. However, according to technical experts in the automotive field, if the driver frequently applies the brakes when going downhill, the brakes will heat up and easily lead to brake pads burning and brake failure. Therefore, when stopping on long steep slopes at a speed limit, drivers should get into the habit of using semi-automatic gear shifting or features such as downhill assist... to take advantage of engine braking to slow the car down.

Hill Descent Control is activated via the control button.

The DAC or HDC downhill assist system integrated into today's car models is very easy to use. When driving downhill, the driver only needs to activate the system through a button usually located on the center console or near the gear shift. When the downhill assist system is active, the driver does not need to brake but only needs to focus on observing and adjusting the steering wheel.

On steep slopes, if the vehicle speed is pushed up by inertia, the vehicle automatically applies additional braking force to maintain the appropriate speed. The system will deactivate when it senses the driver stepping on the accelerator or when the vehicle is moving on a flat road.

According to TNO