2.2 - Primary Safety: Preventing Accidents

Version 6


    Primary safety refers to all technologies and systems designed to avoid accidents, whether they apply to the car, the driver or infrastructures. It covers an extremely vast field that revolves around three complementary focus areas:


    • Primary driver safety: courses in driving and ecodriving, road safety campaigns, awareness-raising campaigns on the risk of accidents, police controls, on-board warning and call-back systems


    • Primary vehicle safety: ABS (Anti-lock Braking System), ESP (Electronic Stability Program), BAS (Brake Assist System), skid control, obstacle detection with automatic braking, distance control, cross-traffic assist, etc.


    • Primary infrastructure safety: signage, road markings, communication and warning systems, speed limits, traffic lights, roundabouts and traffic calming devices, changes in road design, treatment of dangerous points, road maintenance and equipment, improved road surfaces, etc.


    These various systems are even more effective when used in conjunction. Brake-assist systems, for example, work even better when the driver remains vigilant and has at least basic training in braking. Similarly, their contribution to safety is at its peak on well-maintained roads that have signage to show high-risk areas, and which give drivers timely warning of traffic jams or accidents ahead, and so on.


    Primary driver safety: changing behavior


    According to the LAB (Laboratory of Accident Research, Bio-mechanics and the Study of Human Behavior), over 80% of road accidents are caused by human error. So action to change drivers' behavior at the wheel is probably the most effective way of avoiding accidents. This action takes a variety of forms, from information sessions in schools to road safety campaigns, and including either pre- or post-licensing training courses, and police controls.

    Below is an overview of the main systems in use today:


    • Road safety education and awareness training in schools
    • Preliminary training for future drivers, including driving sessions accompanied by a designated experienced driver. In Australia, for example, this system of accompanied driving, called L17, has been shown to work: drivers who learned to drive using the L17 system have 15% fewer accidents in their first 10,000 kilometers than drivers who took formal training.
    • Driver's license with a penalty points system: drivers who commit traffic offenses are encouraged to take a driving course, and drivers who lose all their points have to take their license test again
    • Graduated driver licensing, where the initial restrictions are lifted as the driver gains experience and passes successive tests
    • Differentiated driver's licenses, with special requirements and restrictions for certain categories of driver (young people, elderly people, etc.)
    • Road safety laws and regulations, control and penalty systems: controls and awareness-raising operations conducted by law enforcement officers, speed traps, video surveillance, breathalyzer tests, etc.
    • Eco-driving awareness-raising and training courses, run essentially by employers, road safety associations, insurance companies and government bodies
    • Road safety campaigns aimed at either the general public or specific target groups (young people, pedestrians, etc.) and risks (drink driving, drowsiness, speeding, driving without a license, etc.)
    • Messages, campaigns and road safety tools broadcast over social networks and social media.

    In Mexico, for example, an automaker brought out a mobile application that automatically blocks calls and message tones when the driver is behind the wheel. Texting and talking on mobile phones while driving is responsible for thousands of road deaths every year in Mexico.

    • Warnings and information broadcast over road signs or in-vehicle messaging systems. Highway authorities in many countries use such systems in reverse by encouraging motorists to report incidents and hazards encountered on the road (faulty traffic lights, potholes, etc.).

    In the United States, for example, several states have rolled out the "Report a Road Problem" program, which provides special call numbers and interactive services for road users to use.

    • In-vehicle intelligence systems are capable of warning drivers of all sorts of risks, including dangerous driving styles, potential road hazards, traffic jams or poor traffic conditions, weather conditions, etc.


    Primary vehicle safety: an abundance of innovations



    Automobile manufacturers channel a substantial share of their investment into active safety, which is a core component of their brand image, the reasons buyers purchase their cars, and their models' popularity on the market. A non-exhaustive list of the most significant innovations to appear in recent years follows:




    ABS (Anti-lock Braking System)

    Braking assistance

    ESP (Electronic Stability Program)

    Electronic trajectory corrector, which reduces the gap between where the driver wants to go and where the vehicle is actually heading

    Skid control

    System that stops the wheels from skidding when the car moves off or accelerates, especially on wet or slippery roads

    BAS (Brake Assist System)

    Assists emergency braking

    ESC (Electronic Speed Control)

    A speed controller that helps the driver maintain a steady speed without touching either the brake pedal or the accelerator

    ACC (Adaptive Cruise Control)

    An adaptive speed controller that maintains a safe distance between the car and the vehicle in front, and warns the driver if the car gets too close

    Steering Assist

    System that detects obstacles, rails and road edges, and makes cornering and vehicle trajectories safer if necessary by applying torque to the steering wheel

    Lane Assist

    System that warns the driver if the vehicle veers off-course or unintentionally crosses a line

    Anti-collision system

    Sensors and radars drive a system that warns the driver and automatically applies the brakes in the event of an imminent collision

    Cross-traffic Assist

    System comprising radar sensors and a video camera, which detects vehicles arriving from the side and warns the driver, then automatically brakes if the driver does not react

    Pedestrian Detection

    Combined camera and radar system that detects pedestrians in front of the vehicle and activates automatic braking if the driver is slow to react. This type of system can also work at night, using an infrared camera

    Drowsiness Detector

    System that picks up the signs of drowsiness or fatigue (sudden movement after a period of immobility at the wheel, veering off course, random driving style, etc.) and sends the driver a signal (sound, visual signal or vibration) to rouse him/her

    Blind spot detector

    Optical or radar sensor fitted to the outdoor mirror, which detects the presence of vehicles in the blind spot and activates a signal

    Sign Assist

    System that detects road signs and displays them inside the vehicle

    High-performance tires

    Tires that optimize that main safety criteria: grip (dry, wet, snow and ice), road holding (dry, wet, snow and ice), braking (dry, wet, snow and ice), emergency avoidance, hydroplaning, etc.

    Tire monitoring system

    System that automatically warns the driver if it detects something wrong with the tires (under- or over-inflation, flat tire, etc.)

    Directionally adaptive headlights

    Car headlights adjust to the steering wheel angle, vehicle speed, traffic conditions and ambient light

    Fog lights

    Lights designed for use in mist and fog

    HUD (Head-Up Display)

    System that displays information on the windshield so that the driver does not have to take his/her eyes off the road





    Passive safety could enter a new phase of development in the future with the emergence of vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) connections.

    • In a V2V approach, vehicles automatically exchange information about the hazards they encounter (traffic jams or slowdowns, slippery roads, obstacles, etc.). They can also exchange information about their position, speed and other parameters, which the onboard computer checks for a risk of collision.
    • In the V2I approach, which dovetails with the V2V approach, roadside transmission systems send motorists information and warning messages (about road works, traffic jams, icy patches, etc.). In exchange, a car can report problems or special hazards to the road operator through the infrastructure.

    In Europe, for example, the C2C (Car-to-Car) consortium brings various automakers, OEMs, research laboratories and road operators together to draw up a common protocol for exchanging data between vehicles or between vehicles and infrastructures. The first V2X systems (X being either another vehicle or an infrastructure) should be appearing on the market shortly.


    Primary infrastructure safety



    Primary safety covers all the measures taken to avoid accidents. It therefore includes virtually everything that goes into making roads, from traffic calming systems to road signs, and including lighting and road surfaces.


    However the concerns and the constraints vary widely with the level of economic development. In emerging countries, investments are channeled principally into building new infrastructures (roads, railways, airports, etc.) to keep step with the countries' urban and industrial expansion. Only afterwards will countries invest in primary safety, usually to tackle the most pressing problems. This generally means reducing congestion and making roads safer, since two-wheel vehicles, cars, trucks and pedestrians all use the same road, in a blend that increases the likelihood of accidents exponentially. In Gabon, for example, the government recently launched a program to build around 100 footbridges so that pedestrians can cross the country's main roads, which have become very dangerous as a result of dense, disparate traffic that generally is not subject to any speed limit.


    In developed countries, the vast majority of road infrastructures are equipped with all of the basic primary safety equipment. New investments are mostly split between two priorities:

    • Honing the existing systems in order to further whittle down the number of accidents. For instance, road surface manufacturers are developing high-traction coatings to treat skid zones (dangerous bends, steep slopes) and braking zones (traffic lights, intersections, pedestrian crossings, etc.).
    • Blending all primary safety systems into a comprehensive approach to accident prevention.


    This approach revolves around the concept of "self-explaining roads", i.e. roads that are easy to understand at a glance, where the road equipment, design and signage help motorists anticipate their next moves (cornering, braking, changing direction, etc.) and adopt a low-risk driving style suited to each type of road. In 2011, the authorities in the city of Auckland in New Zealand converted all the road infrastructures in a specific area to "self-explaining road" features so that they could monitor and analyze the resulting changes. The result was a 30% reduction in the number of accidents and an 80% reduction in the cost of accidents over a year.

    Efforts to incorporate the various systems and tools that contribute to primary safety (and also secondary and tertiary safety) are also continuing as part of research and development on intelligent infrastructures, which communicate amongst themselves and with vehicles to regulate traffic flows, anticipate risks and warn of danger. In the United States, for example, the Department of Transportation recently launched a life-size trial of intelligent vehicles and infrastructures in Ann Arbor (Michigan). Over 3,000 cars, trucks and coaches will communicate with each other and with road signage systems, using Wi-Fi technology, to report risks or incidents encountered on the road and mutually regulate speeds, approaches and cross-traffic.