Road Safety Dictionary
Welcome to the Aleatica Foundation’s “Dictionary of Road Safety Terms.” This dictionary aims to familiarize the general public with the concepts and definitions used in the field of road safety and sustainable mobility, in order to raise awareness and knowledge about the importance of safety on public roads.
In this dictionary, you will find a list of key terms related to road safety and sustainable mobility, along with their brief and clear definitions. This information will help you understand and effectively apply these concepts in your daily life, whether you are a driver, pedestrian, public transport user, or any other role you may play when traveling through public spaces on your street, city, or country.
Road safety is a priority for Fundación Aleatica and we hope that this dictionary helps you understand and apply best practices to guarantee road safety on public roads. Thanks for visiting us and we hope that this tool is useful to you!
In addition to this initial section of terms, at Fundación Aleatica, we believe that the “Road Safety Terms Dictionary” can be a tool in constant evolution that is fed by the experiences and knowledge of users and road safety experts. We invite you to submit your recommendations and comments, to help us improve and expand this dictionary. We want this project to be useful to everyone and we’re counting on you to make that happen. Feel free to reach out!
This first version of the dictionary has been prepared by the team of specialists at Alianza Nacional por la Seguridad Vial (ANASEVI A.C.). We hope you find it very helpful in helping you have a better understanding of the fundamental terms used in this field. We also commit to keeping this dictionary up to date and continuing to expand it with terms to offer increasingly more complete and updated information.
Click on a letter to go directly to it. To return to this section, click on the large print in the first column.
ABS brakes
Anti-lock braking system that allows the driver to maintain control of the vehicle during emergency braking.
Accessibility
Set of measures aimed at ensuring that people with disabilities have equal access to physical environments, transportation, information and communications, including information systems and technologies, as well as other services and facilities open to the public or for public use.
Active safety
Set of vehicle systems that prevent accidents from occurring (e.g., ABS brakes, stability control, lighting, signage).
Airbag
A passive safety device that is activated during a collision to reduce injuries by absorbing the impact.
Autonomous vehicle
Vehicle that can operate without human intervention thanks to sensors, artificial intelligence, and automated navigation systems.
Awareness
Communication and educational actions aimed at raising awareness on the importance of respecting traffic rules and culture.
Bicycle lane
Infrastructure reserved partially or totally for the use of bicycles. It can be segregated, shared, or delimited on the roadway.
Bike lane
Exclusive or priority infrastructure for bicycle traffic.
Blind spot
Area not visible to the driver through their mirrors, where other vehicles or vulnerable road users may be present.
Braking distance
The distance a vehicle travels from the moment the brake is applied until it comes to a complete stop. It increases with speed and adverse conditions.
Breathalyzer
A device that measures the concentration of alcohol in exhaled breath. In Mexico, the limits are:
Individual drivers: 0.25 mg/L (air) or 0.05 g/dL (blood)
Motorcyclists: 0.1 mg/L (air) or 0.02 g/dL (blood)
Public transport/freight: zero alcohol
Motorcyclists: 0.1 mg/L (air) or 0.02 g/dL (blood)
Public transport/freight: zero alcohol
BTR transport
Mass public transport system operating with high-capacity buses, dedicated lanes, and specific stations.
Bus stop
A marked location where buses pick up or drop off passengers.
Carpooling
A way for people to share a ride to the same place for reasons of efficiency, sustainability, and cost savings.
Child restraint systems
Devices designed to protect children under 12 years of age in the event of an accident, adapted for use according to weight and height.
Circular junction
Circular intersection where vehicles circle around a central traffic island. It promotes smooth and safe traffic flow through orderly access.
Complete street
A road designed according to principles of safe and accessible mobility, which prioritizes pedestrians, cyclists, and public transportation, following universal design criteria.
Construction zone
Area where maintenance, construction, or road improvement work is being carried out, usually marked with signs and temporary restrictions.
Curvature
Degree of deviation of a road from a straight line. Poorly designed curves increase the risk of accidents.
Cyclist
Person traveling by bicycle, whether human-powered or electrically assisted.
Daytime running lights
Front lights that turn on automatically with the vehicle to increase visibility during the day.
Defensive driving
Driving based on anticipation and risk prevention. Includes: maintaining a safe distance, anticipating other users’ mistakes, obeying traffic signs, avoiding distractions, and maintaining emotional control.
Disability
Any reduction or lack of capacity (as a result of an impairment) to perform an activity in the manner or at the level considered normal for a human being.
Discrimination on the grounds of functional diversity
Any differentiation, exclusion, or restriction that limits or prevents persons with functional diversity from fully exercising their rights.
Distraction
Anything that diverts the driver’s attention, such as cell phones, screens, conversations, food, among others.
Driver
Person who has operational control of a vehicle in traffic.
Emergency exits
Evacuation routes in vehicles or enclosed spaces, designed to be used exclusively in emergency situations.
Emergency lane
Side area of a highway intended exclusively for emergency stops or emergency vehicle traffic.
Emergency lights
Flashing lights of a vehicle used to indicate an emergency situation or a vehicle stopped on the highway.
Emergency vehicle
Vehicle intended for urgent response to critical situations: ambulances, patrol cars, fire trucks, among others.
Escape route
Emergency route that allows you to get out of a dangerous situation on high-speed roads or in confined spaces.
Exclusive lane
Traffic space reserved for certain vehicles (buses, bicycles, BRT), in order to improve efficiency and safety.
Following distance
The safe distance a driver should maintain from the vehicle in front to avoid collisions in the event of sudden braking.
Gender awareness
Design and implementation of policies and programs that address structural inequalities between women and men in mobility.
Hazard lights
Flashing lights used to warn of a dangerous situation, forced stop, or the presence of obstacles.
Head trauma
Injury to the head during a traffic accident. Can involve damage to the scalp, skull, or brain.
Highway
Controlled access expressway, designed exclusively for motor vehicles, with entrances and exits via ramps or junctions.
Hybrid vehicle
Vehicle powered by a combination of an internal combustion engine and an electric motor.
Hydroplaning
Loss of contact between tires and pavement due to water accumulation, which reduces vehicle control and increases the risk of accidents.
Intersection
Point where two or more roads cross. Requires control by means of signage, traffic lights, and roundabouts to avoid conflicts.
Intersectionality
Recognition that a person may face multiple forms of inequality simultaneously (based on gender, age, ethnicity, functional diversity, etc.), which increases their vulnerability on the road.
Last-mile transport
Final stage in the transfer of goods from the logistics center to the end consumer. Essential for urban logistics.
Level crossings
Intersections where a railroad track and a roadway cross at the same level, requiring warning devices and barriers.
Load limit
Maximum weight allowed for a vehicle, including its own weight and that of its load.
Loading and unloading zone
Space reserved for brief logistics operations without obstructing general traffic.
Low-emission zone
Urban area where polluting vehicles are restricted to improve air quality.
Maximum speed limit
The limit established by regulations for driving on a given road. It must be appropriate for the environment, type of road, and presence of vulnerable users.
Median
Physical area separating opposite directions of traffic on a road.
Mobility
The ability of people and goods to move around in public spaces using different modes of transport (walking, cycling, motorized, etc.).
Mobility hierarchy
Principle that guides road design and planning by prioritizing the most vulnerable actors: Pedestrians, with an emphasis on people with functional diversity and limited mobility. Cyclists and non-motorized vehicles. Public transport users and providers. Freight and cargo transport. Personal vehicles.
Mobility pyramid
Hierarchical framework that prioritises the most sustainable and safest modes of transport, placing pedestrians and cyclists at the top and private cars at the bottom.
Mobility systems
A set of infrastructure, vehicles, technologies, and regulations that enable the safe and efficient movement of people and goods.
Motorcycle
Motorized vehicle with two or more wheels, powered by a combustion or electric engine. Includes scooters, three-wheelers, four-wheelers, among others.
Overtaking
Maneuver in which one vehicle passes another moving vehicle traveling in the same direction. Requires adequate visibility and safety conditions.
Passing
A maneuver performed by a driver to move ahead of another vehicle moving in the same direction.
Passive safety
Systems that protect occupants when an accident occurs (seat belts, airbags, deformable structures).
Pedestrian
A person traveling on foot or with assistive devices (wheelchair, cane, walker, etc.). People who use skates, skateboards, or push strollers or carry loads are also considered pedestrians.
Pedestrian collision
A road traffic incident in which a vehicle strikes a pedestrian, causing injury or fatality. It should not be referred to as an “accident” as it is preventable.
Pedestrian crossing
Marked area allowing pedestrians to cross safely. May include traffic lights, zebra crossings, lighting, or elevation.
Pedestrian knockdown
Traffic accident in which a vehicle strikes a pedestrian, causing injury or death. Should not be considered an ‘accident,’ as it is preventable.
Pedestrian overpass
An elevated or underground structure that allows people to safely cross high-speed or multi-lane roads.
Pedestrian walkway
An elevated or underground bridge that allows people to safely cross high-speed or multi-lane roads.
Pedestrianization
An urban measure that restricts or eliminates vehicular traffic in certain areas to prioritize pedestrian use.
Peripheral vision
Driving technique involving indirect side vision to identify hazards without taking your main gaze off the road.
Photo radar fine
An economic fine levied against a violating driver, captured by photo and video cameras installed on public roads.
Priority
Right of way granted to certain users or vehicles on public roads, determined by signage or regulations.
Priority (Right of way)
The legally recognized right of certain users or vehicles to proceed before others, as defined by signage or regulations.
Protective barrier
Physical structure installed to prevent vehicles from veering off the road and reduce the severity of impacts.
Public road
Commonly used space intended for traffic, social interaction, or the provision of public services.
Public road customer
Any person traveling on the road, whether as a pedestrian, cyclist, passenger, or driver, in motorized or non-motorized vehicles.
Public transport
Collective passenger transport service, regulated by authorities, which can operate at the local, metropolitan, or interurban level.
Pylon
Road signage device used to define work or danger zones on the public road.
Residential zone
Urban space predominantly used for housing, where priority is given to pedestrians and reduced speeds.
Risk factor
Element or behavior that increases the likelihood of a traffic accident. Examples: speed, alcohol, distraction, poor visibility.
Road
Space legally designated for the transit of people and vehicles. It includes streets, highways, motorways, paths, trails, etc.
Road accident
Unexpected event that occurs on the public roadway and involves one or more vehicles, pedestrians or cyclists, and that may result in injuries or physical damages. This can be accurately referred to as a Road Mishap, as it is something unpredictable.
Road coexistence
An ethical principle of mutual respect among all road users, promoting a culture of collective care.
Road curvature
The degree to which a road deviates from a straight line. Poorly designed curves increase crash risk.
Road education
Activity aimed at promoting road culture among the population, targeted at all people who use the roadway, with the goal of generating change in social behavior patterns.
Road infrastructure
Set of physical and functional elements (roads, sidewalks, bike lanes, traffic lights, signage, pedestrian bridges) designed to ensure the safe movement of people and vehicles.
Road maintenance
Set of technical interventions aimed at preserving or improving the functional conditions of roads to ensure safety and comfort.
Road network
System comprising all interconnected roads in a territory, including their physical structure, regulations, and operation.
Road safety
Set of policies, actions, technologies, and behaviors aimed at preventing traffic accidents and minimizing their consequences.
Road safety audits
Technical assessments applied to road infrastructure projects with the aim of identifying and correcting risks before accidents occur.
Road Safety Education
Training process aimed at promoting safe, responsible, and considerate behavior when sharing the road.
Road sharing
An ethical principle of mutual respect between different road users, promoting a culture of collective care.
Road system
Comprehensive set of roadways in common use that comprise the urban area.
Road user
Any person using the road, whether as a pedestrian, cyclist, passenger, or driver, via motorized or non-motorized means.
Roadway
Physical space intended for the transit of pedestrians and vehicles.
Roundabout
A circular intersection in which vehicles already inside have the right of way. It allows for safe and efficient turns.
Safe school routes
Measures and infrastructure implemented to ensure that children and adolescents can get to school safely, whether on foot, by bicycle, or by school transport.
Safe system
A comprehensive approach based on the acceptance of human error, which requires that infrastructure, vehicles, regulations, and speed management are designed to protect life at all times.
Safe systems
Coordinated set of strategies and policies that redistribute responsibility for road safety among all stakeholders, prioritizing the reduction of fatalities and serious injuries.
Safer vehicles
Vehicles designed to reduce both the likelihood of accidents and the severity of their consequences. They include structural features and advanced safety technologies.
Safety cone
An item used to mark work zones, detours, or temporary hazardous situations on the road.
Safety device
System or mechanism intended to protect life, health, and integrity during travel. Examples: seat belt, helmet, airbag.
Safety helmet
Personal protective equipment that reduces the risk of head injuries. It is mandatory for motorcycle users.
Safety perimeter
Free space that must be maintained around vehicles or objects to ensure visibility and safe maneuverability.
Safety zone
Space protected for vulnerable customers, especially pedestrians, by means of signage or physical barriers.
School zone
Area near educational centers where special measures must be taken to reduce speed, signage, and surveillance.
Seat belt
Device that restrains vehicle occupants, reducing the risk of injury or death in the event of an accident.
Security zone
Designated area where pedestrians or vehicles are protected from other vehicles in motion, often using physical barriers.
Self-driving vehicle
Vehicle capable of driving and navigating on its own without human intervention.
Self-explaining roads
Roadways designed so that the intended behavior of drivers is intuitive, using visual elements, clear signage, and landscaping.
Self-explanatory roads
Roads designed to make the right driving behavior intuitive through visual cues, clear signage, and landscaping.
Service road
A secondary road built to provide access to nearby properties or support the operation of a main road.
Shock absorbers
Part of the vehicle’s suspension system that reduces the impact caused by uneven terrain.
Shocks
Part of a vehicle’s suspension that absorbs the impact and vibrations of the road.
Shoulder
Space along the side of a highway or road used for vehicles to stop in case of emergency.
Sidewalk
Space designated for pedestrian traffic, generally located on the sides of the road.
Signaling
Set of permanent or temporary visual elements that guide or regulate traffic (vertical, horizontal, light or sound).
Solid line
Road marking indicating that changing lanes or overtaking is prohibited due to visibility or safety conditions.
Speed bump
Physical element (speed bump, rumble strip, speed hump) designed to force vehicles to slow down.
Speed camera
Fine imposed by automatic electronic devices (radars, cameras) that detect violations without the presence of an officer.
Speed limit
Maximum speed permitted by law for driving on a public road.
Speed management
Set of regulatory, technological, urban, and educational measures aimed at ensuring that vehicles travel at appropriate speeds to prevent serious injuries or fatalities in the event of an accident.
Speed radar
An electronic device that measures vehicle speed to detect infractions and issue fines.
Speeding
Driving at a speed higher than that permitted by law or that is inappropriate for the conditions of the environment.
Stop sign
A traffic sign that indicates to the driver the need to bring the vehicle to a complete stop before proceeding, usually at intersections or pedestrian crossings.
Sustainable mobility
A mobility model that reduces the environmental and social impact of transportation by promoting non-motorized modes, public transportation and energy efficiency.
Systemic Approach
Comprehensive perspective that considers all components of mobility (infrastructure, vehicles, users, regulations, speed) as interdependent elements.
Toll
A fee that must be paid to use certain roads, used for maintenance or infrastructure financing.
Toll evasion
Action of traveling on a toll road without making the corresponding payment.
Towing service
Service intended to move immobilized or damaged vehicles off the road to clear traffic and ensure safety.
Traffic accident
Event on a public road involving at least one vehicle and causing loss of life, injury (including those resulting in functional impairment) or property damage. It is preventable and should not be considered an ‘accident.’
Traffic circle
Circular intersection where the vehicles driving around it have the right-of-way over those that want to access it.
Traffic claim
Any event, fact, accident or incident on the public roadway arising from the transit of vehicles or people, involving at least one vehicle and that causes death or injuries, including those causing a disability, or physical damages, that are preventable and the adverse effects of which can be lessened.
Traffic cone
A device used to mark construction zones, detours, or temporary hazards on the road.
Traffic control devices
Set of signs, markings, and elements used to regulate traffic on public roads, including traffic lights, signage, cones, etc.
Traffic crash
An event on a public road involving at least one vehicle that results in death, injury (including disabilities), or property damage. It is preventable and should not be called an “accident.”
Traffic light
Lighted device that regulates vehicle and pedestrian traffic using sequential colors.
Traffic light coordination (Signal timing)
A system for regulating traffic flow through light signals (red, amber, green) to manage movement at intersections and pedestrian crossings.
Traffic lights
Traffic control system using lights (red, amber, green) to manage traffic at intersections or pedestrian crossings.
Traffic management
Actions aimed at organizing, regulating, and controlling the flow of vehicles and people to improve road safety and travel efficiency.
Traffic radar
Electronic device that measures vehicle speed to detect violations and issue penalties.
Traffic regulations (Traffic laws)
A set of legal provisions that regulate the movement of vehicles, pedestrians and other users on public roads. It establishes rights, obligations and penalties.
Traffic sign
Device, mark, or indication that informs, warns, or regulates the behavior of road users.
Traffic signage
A set of permanent or temporary visual elements used to guide or regulate traffic (vertical, horizontal, luminous, or auditory).
Traumatic brain injury
A head injury resulting from a traffic crash, potentially affecting the scalp, skull, or brain.
Travel
Journey made by a person between a point of origin and a destination for a specific purpose, using one or more modes of transport.
Trips (Displacements)
The movement of a person from one origin to a destination for a specific purpose, using one or more modes of transportation.
Two-way road
A road where vehicles travel in opposite directions, usually separated by a center dividing line.
Two-way traffic
A roadway where vehicles travel in opposite directions, typically separated by a center line.
Universal design
Design of products, services, and infrastructure that can be used by all people, without the need for special adaptations. This does not exclude the use of technical aids for persons with functional diversity.
Urban construction zone (Construction zone)
An area where road maintenance, construction, or improvement work is underway—usually marked and subject to temporary restrictions.
Vehicle inspection
Periodic review of the condition and safety of a vehicle to authorize its use on the road.
Vehicle safety
Technical features of the vehicle designed to prevent accidents or mitigate their consequences. Includes active and passive safety elements.
Vehicle safety devices
Equipment incorporated into vehicles to prevent accidents (active safety) or reduce their severity (passive safety), such as ABS brakes or airbags.
Visibility
User’s ability to perceive their surroundings on the road, influenced by lighting, weather conditions, signage, and obstacles.
Vulnerable customers
Children under 12, older adults, people with limited mobility or functional diversity, as well as users of two- and three-wheeled vehicles.
Vulnerable groups
People who face greater challenges in exercising their right to safe mobility: people with disabilities, children, adolescents, older adults, women, low-income people, indigenous communities, and LGBTTTIQ+ people.
Vulnerable road customers
People exposed to greater risks in traffic due to their physical condition, age, or mode of transportation. Includes pedestrians, cyclists, motorcyclists, children, older adults, and people with functional diversity.
Vulnerable road users
Individuals at higher risk in traffic due to physical condition, age, or transport mode. Includes pedestrians, cyclists, motorcyclists, children, older adults, and persons with disabilities.
Wrong way
A situation in which a vehicle is traveling in the opposite direction to that established.
Yield sign
Sign indicating that drivers must allow right-of-way to other vehicles or pedestrians with priority of way.
Zebra crossing (Pedestrian crossing)
A repeated concept — consolidated under “Pedestrian crossing” in earlier entries.
Zone
Urban space predominantly used for housing, where priority is given to pedestrians and reduced speeds.
Zone for loading/unloading
A reserved area for brief logistics operations without obstructing general traffic.
Zone near schools (School zone)
An area near educational centers where special speed reduction, signage, and enforcement measures apply.
Zone of low emissions (Low-emission zone)
An urban area where the circulation of polluting vehicles is restricted to improve air quality.
Zone of safety (Safety zone)
A protected space for vulnerable users, especially pedestrians, using signage or physical barriers.
Zone with pedestrian priority (Residential zone)
An urban area primarily used for housing, where pedestrian priority and reduced vehicle speeds are enforced.