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.
Median
A physical divider that separates opposing traffic flows on a road.
Mobility
The capacity to move people and goods through public space using different modes (walking, cycling, motorized transport, etc.).
Mobility hierarchy
A principle guiding road design and planning by prioritizing the most vulnerable road users.
Mobility pyramid
Conceptual model that ranks the different methods of transportation based on their environmental impact and road safety. At the top of the pyramid are sustainable and safe methods, like walking or cycling, while at the bottom are more dangerous and polluting forms of transportation, like cars.
Mobility systems
The combination of infrastructure, vehicles, technologies, and regulations that enable the safe and efficient movement of people and goods.
Motorcycle
A motorized vehicle with two or more wheels, powered by either a combustion or electric engine. Includes scooters, trikes, ATVs, and others.
Overtaking
A maneuver in which one vehicle passes another moving in the same direction. Requires appropriate 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 in the event of a crash (seat belts, airbags, crumple zones).
Pedestrian
A person traveling on foot or using assistance devices (wheelchair, cane, walker, etc.). Also includes individuals on skates, skateboards, or pushing strollers or cargo.
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 overpass
An elevated or underground structure that allows people to safely cross high-speed or multi-lane roads.
Pedestrianization
An urban measure that restricts or eliminates vehicular traffic in specific areas to prioritize pedestrian use.
Peripheral vision
A driving technique that uses indirect lateral vision to detect hazards without diverting one’s main focus from 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)
The legally recognized right of certain users or vehicles to proceed before others, as defined by signage or regulations.
Protective barrier
A physical structure installed to prevent vehicles from leaving the roadway and to reduce the severity of impacts.
Public road
A space for common use intended for transit, social interaction, or the provision of public services.
Public transport
A regulated collective service that transports people locally, regionally, or between cities.
Pylon
Road signage device used to define work or danger zones on the public road.
Rearview mirror
Mirror that allows the driver to see the vehicles or people who are behind the vehicle.
Residential zone
An urban area primarily used for housing, where pedestrian priority and reduced vehicle speeds are enforced.
Risk factor
An element or behavior that increases the likelihood of a road traffic crash. Examples include speed, alcohol, distraction, and poor visibility.
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
A set of physical and functional elements (roads, sidewalks, bike lanes, traffic signals, signage, pedestrian bridges) designed to ensure the safe movement of people and vehicles.
Road maintenance
A set of technical interventions aimed at preserving or improving road conditions to ensure safety and comfort.
Road network
The system comprising all interconnected roadways in a given area, including their physical structure, regulations, and operations.
Road Safety
A set of policies, actions, technologies, and behaviors aimed at preventing road traffic crashes and minimizing their consequences.
Road Safety Audits
Technical assessments applied to road infrastructure projects to identify and correct risks before crashes occur.
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 (Traffic circle)
A circular intersection where vehicles move around a central island. It facilitates smooth and safe traffic flow through orderly entry and circulation.
Safe school routes
Infrastructure and measures enabling children and adolescents to travel safely to and from educational centers—on foot, by bicycle, or via school transport.
Safe system
A coordinated set of strategies and policies that distribute responsibility for road safety among all stakeholders, prioritizing the reduction of deaths and serious injuries.
Safe systems
Effective, efficient and priority practices that redistribute responsibilities among all the different players involved in mobility rather than just the users, with risk-free roads, transport safety systems in vehicles and safe speeds being particularly relevant.
Safer vehicles
A safer vehicle (including motorcycles) is one that is designed, manufactured and assembled to protect the lives of its occupants and road users outside the vehicle. To this end, they must have safety features that reduce the likelihood of an incident and the severity of the consequences should an incident that could not be avoided occur.
Safety device
A system or mechanism intended to protect life, health, and physical integrity during travel. Examples: seat belt, helmet, airbag.
Safety helmet
Personal protective equipment that reduces the risk of head injuries. Mandatory for motorcycle users.
Safety perimeter
A clear area that must be maintained around vehicles or objects to ensure visibility and maneuverability.
Safety zone
A protected space for vulnerable users, especially pedestrians, using signage or physical barriers.
Seat belt
A device that secures vehicle occupants, reducing the risk of injury or death in the event of a crash.
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.
Service road
A secondary road built to provide access to nearby properties or to support the operation of a main road.
Shock absorbers
A component of a vehicle’s suspension system that reduces the impact caused by road surface irregularities.
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
A designated space for pedestrian movement, typically located along the sides of a road.
Solid line
A road marking indicating a prohibition to change lanes or overtake, due to visibility or safety conditions.
Speed bump (Traffic calming device)
A physical element (hump, rumble strip, raised surface) designed to force vehicles to reduce speed.
Speed camera (Photo radar)
A fine issued via automated electronic devices (radars, cameras) that detect traffic violations without the presence of an officer.
Speed limit
Maximum speed permitted by law for driving on a public road.
Speed management
A set of regulatory, technological, urban, and educational measures aimed at ensuring vehicles travel at appropriate speeds to prevent serious injuries or fatalities in the event of a crash.
Speed radar
An electronic device that measures vehicle speed to detect infractions and issue fines.
Sustainable mobility
A mobility model that reduces the environmental and social impact of transport by promoting non-motorized modes, public transportation, and energy efficiency.
Systemic approach
Approach that addresses mobility as a whole on a comprehensive basis, in which a series of coordinated and interconnected elements interact.
Technical vehicle inspection
Periodic review that must be performed to vehicles to verify their mechanical, electrical and safety condition, and to ensure they comply with the requirements to drive on the public roadway.
Toll
Fee that must be paid to drive on a road or highway in order to fund its maintenance and improvement.
Toll evasion
Act of going through a toll collection point without paying the corresponding fee.
Towing service
Service responsible for removing vehicles that are stranded or have been in an accident on the public roadway.
Towing service
A service used to remove immobilized or crashed vehicles from the roadway to restore safe traffic conditions.
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 device
Set of signs, markings, various devices and other elements placed on roadways to prevent, regulate and guide the flow of pedestrians and vehicles that meet the universal design criteria, guaranteeing appropriate visibility at all times.
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
A signaling device that uses colored lights to regulate the movement of vehicles and pedestrians.
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 management
Actions designed to organize, regulate, and control the movement of vehicles and people to enhance road safety and traffic efficiency.
Traffic regulations (Traffic code)
A set of legal provisions governing the movement of vehicles, pedestrians, and other road users on public roads. It establishes rights, obligations, and penalties.
Traffic sign
A device, marking, or indicator that informs, warns, or regulates the behavior of public 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.
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 traffic
A roadway where vehicles travel in opposite directions, typically separated by a center line.
Universal design
The design of products, services, and infrastructure that can be used by all people without the need for special adaptations. It does not exclude the use of assistive devices for persons with disabilities.
Urban construction zone (Construction zone)
An area where road maintenance, construction, or improvement work is underway—usually marked and subject to temporary restrictions.
Vehicle safety
Measures focused on the performance and protection offered by a motorized vehicle to passengers and users of a roadway against the risk of death or serious injury in the event of a traffic incident.
Vehicle safety devices
Safety devices installed in vehicles—like seatbelts and airbags—that protect the occupants in case of an accident.
Visibility
A road user’s ability to perceive their surroundings, influenced by lighting, weather conditions, signage, and obstacles.
Vulnerable groups
Populations facing greater barriers to exercising their right to safe mobility: persons with disabilities, children, adolescents, older adults, women, low-income individuals, Indigenous communities, and LGBTTTIQ+ people.
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.
Yield (Give way)
A traffic sign indicating that drivers must allow other vehicles or pedestrians with right of way to proceed first.
Zebra crossing (Pedestrian crossing)
A repeated concept — consolidated under “Pedestrian crossing” in earlier entries.
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.