Advanced Driver Assistance Systems are an example of active safety technology, acting like a bigger brother to the ESP® that now comes as standard with all new vehicles. Whereas passive safety technologies such as the airbag or three-point seatbelt reduce harm in the event of a collision, active safety technologies are designed to reduce the likelihood of collisions.

There are lots of different systems from different manufacturers which are examples of ADAS. In a Mercedes Benz you would find ‘Mercedes Benz Driver Assistance’, while on a Cadillac you would find ‘Cadillac Super Cruise’. Though there is some variation between systems, both in variety of function and performance level, they all have the same key elements.

SENSE - Additional sensors capture information about the environment around the vehicle. Radar is widely used for evaluating the proximity of objects, along with LIDAR. Combined with cameras these sensors help the system build a sophisticated 3D reconstruction of the environment around the vehicle.

DETECT – The ADAS system will use the information from its sensor array to detect objects like other vehicles, cyclists, or pedestrians. Many have lane centring or lane keeping functions which detect the white line markings on roads. ADAS systems can also monitor the driver for signs of drowsiness or inattentiveness.

ACT – The ADAS will then act in response to what it detects. These actions will frequently be warnings or signals, but the system will be capable of engaging the braking and steering systems, and reducing acceleration. The sophistication of the system will dictate what interventions the system is capable of making, and when choosing between systems it’s good to understand exactly what you get as standard and what is available as a cost-increasing option.

Lane Departure Warning, Lane Keep Assist and Lane Centring Assist

ADAS typically offers one of these three functions to assist the driver in keeping the vehicle centred in the lane it's travelling in.

Lane Departure Warning (LDW) systems, alert the driver when the vehicle is approaching or crossing the lane markings without having indicated. This alert will be a visual warning plus either an audible alert, or haptic signal such as a vibration in the steering wheel or driver’s seat. Where you have the choice between audible or haptic (silent) alerts you might want to consider the haptic alert. Audible alerts can suggest to passengers that you are not paying due care and attention to the road, and no long journey really needs an additional tension between driver and passenger.

Lane Keep Assist systems nudge the vehicle back into lane, either by braking the opposite front wheel or turning the steering wheel. While these actions are initiated without driver input, the driver can easily countermand the system by steering against it.

At the top end of these systems are the Lane Centring Assist systems which continually adjust the steering to keep the vehicle centred in its lane. These are the most advanced lane monitoring systems and count as a level 2 autonomous driving technology.

All of these systems utilise mounted cameras, typically mounted high in the windscreen, which capture the road markings ahead. They will work less capably in rain or snow, and when visibility is limited will shut off with an alert to the driver. Where lane markings are old LDW can also struggle.

Automatic Emergency Braking (AEB)

Exactly as described, AEB systems will automatically brake in the event of an emergency. These systems will be linked to Forward Collision Detection, Object and Pedestrian Detection, and automatically apply the brakes when the driver is not acting in response to a detected threat.

The EU NCAP safety rating system attributes safety points to cars that have city-AEB and urban-AEB. City-AEB looks 6 to 8 m ahead, detects vehicles and large obstacles to avoid low speed impacts up to 20 km/h to avoid whiplash. Urban-AEB looks up to 200 m ahead and operates over the speed range of 50–80 km/h to avoid driver injuries.

Traffic Sign Recognition (TSR)


These systems utilise the forward mounted cameras to read speed limit signs, traffic lights, and as we move forward an increasing range of road signage. With the increased use of variable speed limits on motorways, the ability of these systems to read speed limit information from roadside and gantry mounted signs is incredibly useful.

Ford’s Traffic Sign Recognition system, for example, captures road signs and displays them graphically on a colour screen. It's able to display two simultaneously, and flashes if you are exceeding the speed limit.

Traffic light forecast functions alongside TSR, but operates using Vehicle to X (V2X) technology to communicate with devices outside of the vehicle. Traffic light forecast assists drivers at junctions by providing information to the driver, and system, about traffic lights ahead. These forecast services include Time To Green (TTG), which relays real time information about the traffic light cycles, and Green Light Optimised Speed Advisory (GLOSA). The latter calculates the optimum approach speed to get a green light at the junction you are approaching.

Adaptive Light Control (ALC)

Adaptive Light Control (ALC) systems react to changes in the environment around the vehicle and adjust the headlight settings on the vehicle. These systems can change the strength, direction, and rotation of the headlights. Glare-Free High Beam and Pixel Light have the ability to detect the lights of approaching vehicles, and redirect the headlights of the vehicle away from the oncoming driver to avoid temporarily blinding them.

Blind Spot Detection (BSD)

The final ADAS component we’ll be considering is one of the most impactful safety-wise, and likely to be the first of these technologies which is mandated on new cars. BSD systems use cameras and/or sensors to monitor the blind spot areas where the driver cannot see easily.

In the example of Nissan, when a radar sensor on the rear bumper detects a vehicle in the blind spot area of an adjacent lane to the driver's vehicle, an indicator light near the side mirror illuminates to alert the driver. If the driver activates the turn signal for the same side as an approaching vehicle, the system alerts the driver with a chime. In addition, the indicator light near the side mirror closest to the intended lane flashes to alert the driver.