Señales de tráficoEstados Unidos
76. Caballo
Un caballo es un animal grande que puede utilizarse para montar, tirar de vehículos u otras actividades. En las carreteras, los caballos pueden formar parte del tráfico mediante jinetes, carruajes o desplazamientos de animales.
Los conductores deben aproximarse despacio y con espacio suficiente, evitar ruidos bruscos y estar preparados para que el animal reaccione de forma imprevisible. Las normas aplicables a caballos y jinetes varían entre países.
Can horses use public roads?
Yes, where local traffic rules permit. Horses may be ridden, led or used with animal-drawn vehicles on public roads and designated routes.
How should drivers behave near a horse?
Drivers should slow down, leave plenty of space and pass calmly, avoiding unnecessary horn use, sudden acceleration or other actions that could frighten the horse.
Are horse riders considered road users?
Yes. Horse riders using a road are road users and must follow the traffic rules that apply to riders and animals in that country.
77. Tráfico local
El tráfico local es el tráfico que necesita acceder a una calle o zona concreta porque su viaje comienza, termina o requiere una parada allí, en lugar de limitarse a atravesarla. Las carreteras pueden estar restringidas al tráfico local para reducir el tráfico de paso innecesario.
El significado exacto depende de las normas nacionales. Suele incluir residentes, visitantes, repartos y vehículos que prestan servicios dentro de la zona restringida.
What does local traffic mean?
Local traffic generally means vehicles that have a legitimate reason to enter a particular street or area, such as reaching a home, business, delivery address or other destination located there.
Is local traffic the same as through traffic?
No. Through traffic passes through an area without having a destination or other necessary stop there. A restriction allowing only local traffic is normally intended to prevent this type of unnecessary through traffic.
Who may enter a road restricted to local traffic?
This depends on national rules and the signs in place. Residents, visitors, deliveries, emergency services and certain service vehicles are commonly permitted, but the precise categories vary between countries.
78. Peatón
Un peatón es una persona que se desplaza a pie por una carretera, calle, camino u otro espacio público. Según la legislación local, las personas que empujan bicicletas, sillas de ruedas, cochecitos u otros pequeños dispositivos también pueden ser consideradas peatones.
Los peatones normalmente utilizan aceras, caminos peatonales y zonas peatonales cuando están disponibles. Al cruzar una carretera o caminar donde no existe una instalación adecuada, deben seguir las normas de cruce, semáforos y otras normas locales de tráfico.
What is a pedestrian?
A pedestrian is primarily a person travelling on foot. Local traffic laws may also treat people pushing bicycles, wheelchairs, prams or certain other devices as pedestrians.
Where should pedestrians normally walk?
Pedestrians should normally use pavements, sidewalks, footpaths or other areas provided for pedestrians. Where these are unavailable, local rules determine where pedestrians may walk on or beside the road.
Which side of the road should pedestrians walk on when there is no pavement?
This depends on the country's traffic rules. Many countries require or recommend pedestrians to face approaching traffic, but the exact rule varies.
Where should pedestrians cross a road?
Use a pedestrian crossing, traffic-light-controlled crossing or other designated crossing where required or reasonably available. Where crossing elsewhere is permitted, choose a location with good visibility and cross carefully.
Do pedestrians always have priority at a pedestrian crossing?
The exact priority rule varies between countries. Drivers are commonly required to give way to pedestrians using or entering designated crossings, but pedestrians must still obey traffic lights and avoid entering the road dangerously.
Must pedestrians obey traffic lights?
Yes. Where pedestrian signals are provided, pedestrians must follow their indications and should not enter the roadway while the signal prohibits crossing.
Is someone pushing a bicycle a pedestrian?
In many traffic systems, a person who dismounts and walks beside a bicycle is treated as a pedestrian. The precise legal classification depends on local law.
Can pedestrians use a cycle path?
This depends on the road layout and local rules. Pedestrians may sometimes use a cycle path when no suitable pedestrian facility is available, but they must not unnecessarily obstruct cyclists or other authorised users.
Do turning vehicles have to watch for pedestrians?
Yes. Drivers turning into another road must watch carefully for pedestrians crossing the road they are entering and give way where required by local traffic law.
What should pedestrians do before crossing a road?
Check carefully for approaching traffic from all relevant directions, make sure there is sufficient time and distance to cross safely, and continue to observe traffic while crossing.
79. Ciclista
Un ciclista es una persona que conduce una bicicleta. Puede circular por la calzada, carriles bici, vías ciclistas u otras infraestructuras según las normas locales.
Los ciclistas son usuarios vulnerables y pueden verse afectados por viento, superficies irregulares, puertas de vehículos y adelantamientos cercanos. Los conductores deben dejar espacio suficiente y comprobar la presencia de ciclistas antes de girar o abrir puertas.
What is a cyclist?
A cyclist is a person who rides and controls a bicycle.
Is a cyclist considered a road user?
Yes. Cyclists are road users and must follow the traffic rules, signs and signals that apply to them.
Where should cyclists ride?
This depends on local rules. Cyclists may be required to use a cycle path or designated cycling facility, while in other situations they may ride on the carriageway.
80. Motocicleta
Una motocicleta es un vehículo de motor de dos ruedas y, según la clasificación legal, también puede incluir determinados vehículos de tres ruedas. Las motocicletas pueden variar desde modelos pequeños hasta máquinas de alta potencia.
Los motociclistas son más vulnerables porque tienen menos protección física y pueden ser difíciles de ver. Otros conductores deben comprobar espejos y ángulos muertos, dejar espacio y valorar correctamente su velocidad.
What is a motorcycle?
A motorcycle is a powered two-wheeled vehicle, which may also be equipped with a sidecar.
Is a motorcycle the same as a moped?
No. Traffic laws generally distinguish motorcycles from mopeds according to technical characteristics such as power, engine capacity or maximum speed.
What protective equipment should a motorcyclist use?
Motorcyclists should use an approved helmet and suitable protective clothing. The exact mandatory equipment depends on the country's traffic laws.
81. Camión
Un camión es un vehículo de motor diseñado principalmente para transportar mercancías o cargas. Puede ir desde vehículos ligeros de reparto hasta vehículos pesados articulados con remolques o semirremolques.
Los camiones suelen tener mayor masa, dimensiones, distancia de frenado y ángulos muertos que los turismos. Pueden estar sujetos a límites de velocidad, restricciones de acceso, tiempos de conducción, peajes y normas de carga específicos.
What is a truck?
A truck is a motor vehicle designed primarily for transporting goods.
Are all trucks considered heavy goods vehicles?
No. Trucks can include lighter goods vehicles as well as heavy trucks. Traffic laws often apply different rules according to the vehicle's maximum authorised mass.
Why should other road users take extra care around trucks?
Trucks may have larger blind spots, longer stopping distances and wider turning paths than smaller vehicles, so other road users should avoid remaining unnecessarily close beside or in front of them.
82. Autobús
Un autobús es un vehículo a motor diseñado para transportar a varios pasajeros, normalmente por carretera como parte del transporte público, escolar, privado u otro servicio de pasajeros. Los autobuses suelen tener mayor capacidad que los turismos y pueden estar diseñados para pasajeros sentados, de pie o ambos.
Pueden aplicarse normas especiales sobre permiso de conducir, capacidad de pasajeros, límites de velocidad, cinturones, carriles bus, paradas y subida de pasajeros. La clasificación legal de autobuses y autocares y las normas aplicables varían entre países, por lo que conductores y pasajeros deben seguir las normas locales de tráfico.
What is a bus?
A bus is a motor vehicle designed to transport a relatively large number of passengers. It may be used for public transport, school transport, private services or other passenger transport.
What is the difference between a bus and a coach?
A bus is commonly designed for frequent passenger boarding and may allow standing passengers, while a coach is generally designed for longer journeys with passengers seated. Exact legal definitions vary between countries.
Do you need a special driving licence to drive a bus?
Yes. Driving a vehicle designed to carry more than a specified number of passengers normally requires a dedicated bus or passenger-vehicle driving licence.
Can passengers stand on a bus?
Only when the vehicle is designed and approved to carry standing passengers. Coaches and other vehicles designed exclusively for seated passengers must not be used beyond their approved passenger configuration.
Must bus passengers wear seat belts?
Where seat belts are provided and local law requires their use, passengers must wear them correctly. Urban buses designed for standing passengers may have seating positions or operating conditions that differ from coaches.
Can buses use bus lanes?
Yes, where permitted. Bus lanes are commonly reserved for public transport buses, although local signs may also allow taxis, bicycles or other specified vehicles to use them.
Do buses always have priority when leaving a bus stop?
No. Some countries require other drivers to give way to buses leaving designated stops, particularly in urban areas, while others apply the normal merging rules.
Should you take extra care near a stopped bus?
Yes. Passengers may be boarding, leaving or crossing the road near the bus. Reduce speed where necessary and watch carefully for pedestrians emerging from behind or in front of the vehicle.
Do buses have special speed limits?
They can. Some countries impose lower maximum speeds on buses than on passenger cars, particularly on high-speed roads. Different limits may apply to buses and coaches.
Can a bus use a motorway?
Yes, normally. Buses that satisfy the applicable construction and access requirements may use motorways, but they must obey any vehicle-specific speed limits, lane restrictions and other local rules.
83. Policía
La policía es la autoridad pública responsable de hacer cumplir las leyes, mantener la seguridad pública y gestionar situaciones que pueden afectar al tráfico. En la circulación, los agentes pueden controlar vehículos, hacer cumplir las normas, investigar colisiones, dirigir el tráfico y responder a emergencias.
Los usuarios deben obedecer las instrucciones legales de los agentes u otro personal autorizado de control. Las indicaciones policiales pueden prevalecer temporalmente sobre semáforos, señales o la organización normal del tráfico, según la legislación local.
What is the role of police in road traffic?
Police help enforce traffic laws, manage traffic, investigate collisions and respond to dangerous situations. They may also carry out roadside checks and direct road users.
Must you obey a police officer directing traffic?
Yes. Lawful directions given by an authorised police officer must be followed. In many countries, those directions take precedence over traffic lights, road signs and normal priority rules.
What should you do if police signal you to stop?
Slow down, follow the officer's directions and stop at a safe location as instructed. Do not make sudden movements or continue driving unless directed to do so.
Can police direct you through a red traffic light?
Yes, where authorised by local law. A police officer controlling traffic may instruct road users to proceed even when a traffic light or sign would normally require them to stop.
Can police check your driving documents?
Yes. Police may require drivers to provide documents such as a driving licence, vehicle registration, identification or proof of insurance according to local law.
Can police carry out alcohol or drug checks?
Yes. Traffic police may conduct legally authorised alcohol and drug checks using procedures such as breath, saliva or other approved tests.
Can police temporarily close a road?
Yes. Roads or lanes may be temporarily closed or traffic diverted because of collisions, emergencies, investigations, public events or other safety concerns.
What should you do near police controlling an accident scene?
Reduce speed, remain alert and follow all directions. Do not enter a closed area or interfere with emergency personnel, and leave sufficient space for emergency vehicles.
What should you do when a police vehicle approaches with emergency signals?
Follow the local rules for priority vehicles. Drivers generally have to make sufficient space, give way and stop where necessary so that the emergency vehicle can pass safely.
Can police order a parked vehicle to be moved?
Yes, where local law permits it. Police or another authorised authority may require a vehicle to be moved when it obstructs traffic, creates danger or must be removed for operational reasons.
84. Ambulancia
Una ambulancia es un vehículo equipado y utilizado para prestar asistencia médica de emergencia o transportar pacientes hasta o entre centros sanitarios. Puede llevar material médico y personal formado capaz de proporcionar tratamiento durante el transporte.
Durante una respuesta de emergencia, puede utilizar luces de emergencia y sirena y recibir prioridad especial o exenciones de determinadas normas. Los demás usuarios deben seguir las reglas locales para vehículos de emergencia, dejar espacio suficiente y evitar obstaculizar su paso.
What is an ambulance?
An ambulance is a specially equipped vehicle used to provide emergency medical assistance and transport sick or injured people.
When does an ambulance have priority?
This depends on the local traffic rules and warning signals being used. Ambulances responding to emergencies commonly use flashing lights and a siren to indicate that other road users must make way.
What should you do when an ambulance approaches?
Remain calm and make sufficient space for it to pass. Slow down or stop where necessary, but avoid sudden or dangerous manoeuvres.
Should you stop immediately when you hear an ambulance siren?
Not necessarily in your exact position. Move or stop in a way that creates a safe passage without blocking an intersection, pedestrian crossing or another part of the road needed by the ambulance.
Can an ambulance pass a red traffic light?
Emergency vehicles may be allowed to pass a red light during an urgent response under special legal conditions. The precise rules differ between countries, and the ambulance driver must still take appropriate precautions.
Can an ambulance exceed the speed limit?
Many countries permit emergency vehicles to depart from certain normal speed rules during an urgent mission, subject to safety requirements and national legislation.
Can an ambulance drive through a traffic queue?
Yes, when responding to an emergency and legally permitted to do so. Other road users should create space and keep emergency corridors or access routes clear where required.
Can you follow an ambulance through traffic?
You should not use the passage created for an ambulance as a way to bypass congestion. Maintain a safe distance and continue to obey the normal traffic rules.
Do ambulances always use their sirens?
No. The use of warning lights and sirens depends on the urgency of the mission and local regulations. An ambulance transporting a patient does not necessarily need to use emergency signals throughout the journey.
What should you do near a stationary ambulance?
Reduce speed and remain alert. Medical personnel, patients or other emergency workers may be entering the road, and the ambulance may need to move unexpectedly.
85. Señales de la policía
Las señales de la policía son gestos, posiciones o indicaciones utilizados por agentes u otras personas autorizadas para controlar el tráfico. Pueden ordenar a los usuarios detenerse, avanzar, cambiar de dirección o seguir otra disposición temporal.
Los usuarios deben observar y obedecer estas señales incluso cuando difieran de las señales o semáforos normales. Los gestos exactos y sus significados varían entre países.
What are police traffic signals?
Police traffic signals are gestures, positions or other signals used by authorised officers to regulate or direct traffic.
Do police signals override traffic lights?
In many countries, yes. Directions given by an authorised traffic officer normally take precedence over traffic lights, signs and ordinary traffic rules.
What should you do if a police officer gives a signal you do not expect?
Slow down, pay close attention and follow the officer's instruction. Do not continue simply because a traffic light or road sign would normally allow you to proceed.
86. Carretera de grava
Una carretera de grava es una vía sin pavimentar recubierta de grava, piedra triturada u otro árido suelto en lugar de asfalto u hormigón. Son habituales en zonas rurales, bosques, obras y lugares donde pavimentar no es necesario o práctico.
Los conductores deben reducir la velocidad cuando sea necesario, aumentar la distancia de seguimiento y evitar frenadas o giros bruscos. Las piedras sueltas, polvo, baches y menor adherencia pueden dificultar el control.
What is a gravel road?
A gravel road is an unpaved road covered with gravel, crushed stone or another loose aggregate surface.
Why can gravel roads be more difficult to drive on?
Loose material can reduce tyre grip, increase stopping distance and cause stones or dust to be thrown into the air. Potholes and uneven surfaces may also be present.
How should you drive on a gravel road?
Use a suitable speed, maintain extra distance from other vehicles and accelerate, brake and steer smoothly to reduce the risk of losing traction.
87. Bache
Un bache es un agujero o depresión en la superficie causado por desgaste, meteorología, agua, cargas repetidas o deterioro del pavimento. Puede variar mucho en tamaño y profundidad y desarrollarse gradualmente o empeorar tras heladas, lluvias intensas o tráfico repetido.
Los baches pueden afectar a dirección, frenada y estabilidad y dañar neumáticos, llantas o suspensión. Los conductores y motoristas deben observar la carretera, adaptar la velocidad y evitar maniobras bruscas o peligrosas.
What is a pothole?
A pothole is a hole or depression that develops in a road surface when the pavement becomes damaged or deteriorates.
How do potholes form?
Potholes can develop through a combination of water, temperature changes, traffic loads and deterioration of the road material. Cracks can gradually expand until pieces of the surface break away.
Why are potholes dangerous?
A pothole can cause a vehicle to change direction suddenly, lose stability or suffer tyre, wheel or suspension damage. Deep potholes can present a particularly serious hazard at higher speeds.
What should you do when you see a pothole?
Reduce speed when necessary, maintain control of the vehicle and avoid abrupt steering or braking. Only move around the pothole when this can be done safely without endangering other road users.
Should you brake while driving through a pothole?
If possible, reduce your speed before reaching the pothole. Sudden heavy braking or steering while passing over a damaged surface can make the vehicle less stable.
Are potholes particularly dangerous for motorcycles?
Yes. A pothole can disturb the steering or balance of a motorcycle and may cause the rider to lose control.
Are potholes dangerous for cyclists?
Yes. Bicycle wheels can be strongly affected by deep holes or sharp edges, particularly when the cyclist has little time or space to avoid the hazard.
Can a pothole damage a car?
Yes. Severe impacts can damage tyres, wheel rims, suspension components, steering parts or wheel alignment.
Should you swerve suddenly to avoid a pothole?
No. A sudden evasive movement may create a greater danger by bringing the vehicle into conflict with cyclists, pedestrians, oncoming traffic or vehicles in another lane.
Can a warning sign indicate potholes ahead?
Yes. Depending on the country's traffic-sign system, an uneven-road or general-danger warning sign may be used where poor road conditions create a significant hazard.
88. Mediana
Una mediana, también llamada separador central, es una zona longitudinal entre calzadas separadas, normalmente destinada a dividir el tráfico que circula en sentidos opuestos. Puede estar formada por césped, pavimento, barreras, vegetación u otro tipo de separación física.
La mediana ayuda a separar los flujos de tráfico opuestos y puede reducir el riesgo de que los vehículos invadan directamente la circulación contraria. Puede disponer de aperturas en lugares seleccionados para giros, intersecciones, acceso de emergencia u otros movimientos autorizados.
What is a median strip?
A median strip is a longitudinal area that separates two roadways, usually carrying traffic in opposite directions.
Is a median strip the same as a road marking?
Not necessarily. A median is normally a physically distinguishable area or structure, while painted centre lines simply separate traffic using road markings.
What can a median strip be made of?
A median may consist of grass, paving, kerbs, safety barriers, vegetation or another physical separation between roadways.
Why are median strips used?
They help separate opposing traffic flows, reduce conflicts between vehicles travelling in opposite directions and provide space for barriers, signs, lighting or other road infrastructure.
Can you drive across a median strip?
Only where a legal crossing or opening is provided and the applicable traffic rules permit the movement. Drivers should never cross a physical median simply to change direction or take a shortcut.
Can a median strip have openings?
Yes. Openings may be provided for intersections, turning movements, emergency services, maintenance or other authorised traffic.
Can you park on a median strip?
This depends on local law, but parking on a median is commonly prohibited or restricted because it may create danger or obstruct visibility and traffic.
Can pedestrians stand on a median strip?
Some medians contain a pedestrian refuge specifically designed to allow people to cross a road in stages. Other medians may not be intended for pedestrian use.
Is a central safety barrier part of the median?
It can be. A median may contain a safety barrier designed to reduce the risk of vehicles crossing into opposing traffic.
Can a divided road have more than one roadway?
Yes. A road with a median commonly has two separate roadways, one for each direction of traffic.
Does a median strip determine the direction of traffic?
The road layout normally separates the traffic directions, but drivers must still follow the traffic signs, lane markings and directional rules applying to each roadway.
Is a median strip the same as an emergency lane?
No. An emergency lane or shoulder runs alongside a roadway, while a median strip separates roadways from each other.
89. Propiedad pública
La propiedad pública comprende terrenos, edificios, infraestructuras u otros bienes propiedad o bajo control de un gobierno u otra autoridad pública. Puede incluir carreteras, parques, plazas, edificios públicos, infraestructuras ferroviarias y otras instalaciones destinadas a servicios públicos.
No necesariamente es de libre acceso para todos. Algunas zonas están abiertas al uso general mientras que otras pueden tener acceso restringido o estar reservadas a determinados servicios. Las normas de tráfico dependen de si el área forma parte de una vía pública u otro lugar al que se aplique la legislación correspondiente.
What is public property?
Public property is property owned or controlled by a government, municipality or another public authority.
What are examples of public property?
Examples can include roads, parks, public squares, government buildings, transport infrastructure and other public facilities.
Is all public property open to everyone?
No. Some public property is freely accessible, while access to government offices, maintenance facilities, railway infrastructure or other areas may be limited or prohibited.
Is public property the same as a public road?
No. Public property concerns ownership or control, while a public road concerns an area that is legally or actually open to public traffic. A public road can therefore be only one type of public property.
Can privately owned land be open to the public?
Yes. A privately owned car park, road or other area may be accessible to the public even though the government does not own it.
Can publicly owned land be closed to the public?
Yes. Public authorities can own areas that are restricted to authorised personnel, maintenance services or other specified users.
Do traffic rules automatically apply to all public property?
No. Whether ordinary road-traffic rules apply depends on the legal status and use of the area rather than simply on who owns it.
Can public property contain roads and parking areas?
Yes. Public property can include streets, car parks, access roads and other traffic areas, each of which may have its own traffic and access rules.
Can access to public property be restricted by signs?
Yes. Signs, barriers, opening hours, permits or other regulations may restrict access to particular public areas.
Can vehicles be prohibited from public property?
Yes. A publicly accessible park, square or pedestrian area may prohibit motor vehicles or permit only specific categories such as emergency, maintenance or delivery vehicles.
Is public property the same as public space?
Not necessarily. Public space generally describes an area available for public use, while public property primarily describes ownership or control. A publicly used space can sometimes be privately owned.
Why is the distinction important for traffic rules?
Traffic regulations frequently depend on whether an area is a public road, publicly accessible place or restricted private area, rather than solely on ownership.
90. Camino
Un camino es una ruta relativamente estrecha destinada a peatones y, cuando esté permitido, a otros usuarios o vehículos pequeños. Los caminos pueden atravesar zonas urbanas, campo, parques, bosques o conectar otras carreteras, y pueden estar pavimentados o no.
Un camino no es necesariamente lo mismo que una acera o vía ciclista. Los usuarios que pueden utilizarlo dependen de su estatus legal, anchura, señales de tráfico y normas locales.
What is a path?
A path is a relatively narrow route intended primarily for pedestrians and, where permitted, other road users or small vehicles.
Is a path the same as a footpath?
Not necessarily. A footpath is specifically intended for pedestrians, while a path may also permit cyclists or other users according to local rules.
Is a path the same as a cycle path?
No. A cycle path is specifically designated for bicycles and other permitted users. An ordinary path does not automatically have that legal status.
Can cyclists use a path?
This depends on the legal status, width and signs applying to the path. Some paths permit cyclists, while others are reserved for pedestrians or particular users.
Can motor vehicles use a path?
This depends on local law. Some paths prohibit motor vehicles entirely, while narrow vehicles may be permitted on other paths unless traffic signs restrict access.
Can a path be part of the public-road network?
Yes. A narrow path can legally form part of the public-road network even when it is unsuitable for ordinary cars.
Does a path need to be paved?
No. Paths can be paved, gravelled, compacted or unsurfaced depending on their location and purpose.
Can traffic signs restrict access to a path?
Yes. Signs can reserve a path for particular road users or prohibit certain vehicles, regardless of whether they could physically fit on it.
Who has priority when a path joins a larger road?
The applicable local priority rules determine who must give way. Special rules often apply when a minor path joins an ordinary road.
Can pedestrians and cyclists share a path?
Yes, where both are permitted. Faster users should adapt their speed and avoid endangering or unnecessarily obstructing pedestrians.
Can a path cross another road?
Yes. At the crossing, users must follow the applicable priority signs, traffic lights, road markings and general right-of-way rules.
Is every narrow route legally a path?
No. Its legal classification depends on the definitions and regulations of the country concerned. A narrow route might instead be a footpath, cycle path, private access road or another type of facility.
91. Partículas
Las partículas, o material particulado (PM), son pequeñas partículas sólidas o gotas líquidas suspendidas en el aire. En el tráfico, las emisiones de partículas pueden proceder de gases de escape, desgaste de frenos, desgaste de neumáticos y desgaste de la superficie vial, además del polvo levantado por el paso de vehículos.
El material particulado suele clasificarse por tamaño. PM10 se refiere a partículas de hasta aproximadamente 10 micrómetros de diámetro, mientras que PM2.5 se refiere a partículas más finas de hasta aproximadamente 2,5 micrómetros. Las normas de emisiones, filtros de partículas y medidas de calidad del aire se utilizan para reducir la exposición a estos contaminantes.
What are particulates?
Particulates, or particulate matter, are very small solid particles or liquid droplets suspended in the air.
What are PM10 and PM2.5?
PM10 refers to particles with a diameter of up to approximately 10 micrometres. PM2.5 refers to finer particles with a diameter of up to approximately 2.5 micrometres.
Where do traffic particulates come from?
Road traffic can produce particles through engine exhaust, brake wear, tyre wear and road-surface wear. Passing traffic can also resuspend dust already present on the road.
Are diesel vehicles a source of particulates?
Yes. Combustion in diesel engines can produce very small soot particles. Modern diesel vehicles commonly use particulate filters to capture a large proportion of these exhaust particles.
What is a particulate filter?
A particulate filter is an exhaust-treatment device designed to trap particulate matter produced by an engine. Diesel particulate filters are commonly known as DPFs.
Do petrol engines produce particulates?
Yes. Petrol engines can also produce particulate emissions, particularly certain direct-injection engines. Appropriate emission-control systems may therefore include particulate filters.
Do electric vehicles produce particulates?
Fully electric vehicles produce no exhaust particulates from a combustion engine, but particles can still result from tyre wear, road wear and braking.
Are brake and tyre particles regulated?
Vehicle-emission regulation is increasingly addressing non-exhaust emissions. The European Euro 7 framework includes requirements concerning brake-particle emissions and tyre abrasion.
Is particulate matter the same as CO2?
No. Particulate matter consists of tiny airborne particles, while carbon dioxide is a gas. They are different types of vehicle emissions and are regulated for different environmental reasons.
How can vehicle particulate emissions be reduced?
Measures include effective particulate filters, cleaner vehicle technologies, correctly maintained emission-control systems and reductions in brake, tyre and road-wear emissions.
92. Contaminación del aire
La contaminación del aire es la presencia de gases, partículas u otras sustancias en concentraciones que pueden perjudicar la salud humana, el medio ambiente o los ecosistemas. El tráfico contribuye mediante emisiones de escape y fuentes no relacionadas con el escape como desgaste de frenos, neumáticos y polvo de la carretera.
Entre los contaminantes importantes del tráfico se incluyen óxidos de nitrógeno, material particulado, monóxido de carbono y compuestos orgánicos volátiles. Algunos se emiten directamente y otros se forman en la atmósfera mediante reacciones químicas. Las normas de emisiones, tecnologías más limpias y medidas de gestión del tráfico ayudan a reducirlos.
What is air pollution?
Air pollution is contamination of the air by gases, particles or other substances that can adversely affect human health, the environment or ecosystems.
How does road traffic cause air pollution?
Vehicles produce pollutants through fuel combustion, exhaust systems, brake wear, tyre wear and road-surface interaction. Moving traffic can also resuspend dust already present on the road.
Which air pollutants are associated with road traffic?
Important traffic-related pollutants include nitrogen oxides, particulate matter, carbon monoxide and volatile organic compounds. Their relative importance depends on the vehicle, fuel and driving conditions.
What is nitrogen dioxide?
Nitrogen dioxide (NO2) is an air pollutant associated particularly with combustion processes and road traffic. High concentrations are commonly found near busy roads and densely trafficked urban areas.
What is particulate matter?
Particulate matter consists of tiny solid particles or liquid droplets suspended in the air. Road traffic can produce particles from exhaust, brakes, tyres and road surfaces.
Is CO2 the same as ordinary air pollution?
No. Carbon dioxide is primarily regulated as a greenhouse gas because of its contribution to climate change. Local air-quality pollution generally focuses on substances such as nitrogen dioxide, particulate matter, ozone and other pollutants that directly affect air quality and health.
Do electric vehicles cause air pollution?
Fully electric vehicles produce no combustion-engine exhaust emissions while driving, but they can still contribute to non-exhaust particulate emissions through tyres, brakes and road wear.
Can air pollution be worse near busy roads?
Yes. Concentrations of traffic-related pollutants can be higher close to heavily trafficked roads because many emissions occur close to ground level and near where people live and travel.
What is a low-emission zone?
A low-emission zone is an area where access by more polluting vehicles is restricted in order to reduce traffic-related air pollution. Access criteria may depend on factors such as fuel type, vehicle category and emission standard.
How can traffic-related air pollution be reduced?
Measures include cleaner vehicles, stricter emission standards, effective emission-control equipment, low-emission zones, public transport, cycling and walking, as well as traffic-management measures that reduce unnecessary congestion and emissions.
93. Enlace
Un enlace es una intersección diseñada para permitir que el tráfico pase entre dos o más carreteras principales, normalmente mediante ramales, puentes o túneles para que las corrientes conflictivas no tengan que cruzarse al mismo nivel. Son habituales en autopistas, vías rápidas y otras carreteras de gran capacidad.
Los conductores deben seguir con antelación las señales de dirección, flechas de carril y números de ruta y elegir el carril correcto antes de la salida o ramal necesarios. Los límites de velocidad, normas de incorporación y disposición de carriles varían entre países y enlaces.
What is an interchange?
An interchange is a junction that allows traffic to transfer between major roads, commonly using ramps and grade-separated bridges or tunnels.
What is the difference between an interchange and an ordinary intersection?
At an ordinary intersection, traffic streams normally meet or cross at the same level. An interchange usually separates major traffic movements vertically and connects them using ramps.
Where are interchanges commonly found?
They are most common on motorways, expressways, ring roads and other high-capacity roads where stopping at ordinary intersections would disrupt traffic flow.
What is an interchange ramp?
A ramp is a connecting road that allows vehicles to enter, leave or transfer between the roads forming the interchange.
How should you approach an interchange?
Read the advance-direction signs early, identify your route or destination and move into the appropriate lane in sufficient time.
Should you make sudden lane changes at an interchange?
No. Interchanges can contain several exits and merging traffic streams. Signal in good time and change lane only when there is sufficient space to do so safely.
Who has priority when entering another road at an interchange?
This depends on the local signs, markings and merging rules. Drivers joining a motorway commonly have to give way to traffic already travelling on it, but local regulations must always be followed.
Can speed limits change on interchange ramps?
Yes. Ramps may have lower speed limits or require a lower safe speed because of bends, merging traffic or limited visibility.
What should you do if you miss your exit at an interchange?
Continue to the next suitable exit or interchange. Never reverse, stop unexpectedly or cross prohibited areas to return to a missed exit.
Are all interchanges designed the same way?
No. Common layouts include cloverleaf, diamond, trumpet and directional interchanges. Their design depends on traffic volumes, available space and the roads being connected.
94. Hora punta
La hora punta es un periodo en el que las carreteras y redes de transporte público tienen una demanda especialmente elevada, normalmente porque mucha gente se desplaza al trabajo, colegio u otros destinos habituales. Suele producirse por la mañana y al final de la tarde o por la noche en días laborables.
Puede causar congestión, velocidades menores, viajes más largos y paradas frecuentes. Los conductores deben mantener una distancia segura, tener paciencia, anticipar cambios del tráfico y seguir cualquier medida temporal o dinámica de gestión.
What is rush hour?
Rush hour is a period when unusually large numbers of people travel at the same time, resulting in increased traffic and often congestion.
When does rush hour occur?
Rush hour commonly occurs during the morning and late afternoon or evening on working days, but the exact times vary according to the city, road and local travel patterns.
Does rush hour always last one hour?
No. The term does not mean that congestion lasts exactly one hour. In busy urban areas, peak traffic conditions may continue for several hours.
Why does traffic become congested during rush hour?
Congestion develops when traffic demand approaches or exceeds the available road capacity. Intersections, merging traffic, collisions, roadworks and weather can make the congestion worse.
Should you increase your following distance in rush-hour traffic?
Yes. Leave sufficient distance to react to sudden braking and frequent changes in traffic speed. Avoid following another vehicle too closely even when traffic is moving slowly.
Should you frequently change lanes during congestion?
Unnecessary lane changes can create additional conflicts and may not significantly reduce journey time. Choose an appropriate lane, observe surrounding traffic and change lane only when it can be done safely.
Can speed limits change during rush hour?
Yes. Roads equipped with variable traffic management may display lower speed limits during congestion. Drivers must follow the speed limit currently indicated.
What is a rush-hour lane?
A rush-hour lane is an additional traffic lane that can be opened during busy periods to increase road capacity. It may use a lane or shoulder that is closed to normal traffic at other times.
Can you use a rush-hour lane whenever traffic is congested?
No. Such a lane may only be used when traffic signals or signs indicate that it is open. Never assume that congestion alone permits its use.
How can you prepare for a journey during rush hour?
Check current traffic conditions and expected journey times, allow additional travel time and consider an alternative route, departure time or mode of transport where appropriate.
95. Estación de servicio
Una estación de servicio es una instalación donde los vehículos pueden obtener combustible como gasolina, diésel u otros combustibles. Muchas también ofrecen carga para vehículos eléctricos, aire para neumáticos, productos para vehículos, aseos, comida o tienda.
Las estaciones junto a grandes carreteras y autopistas suelen indicarse mediante señales de información o servicio. Los conductores deben reducir la velocidad antes de entrar, seguir los accesos designados y tener especial cuidado por el movimiento de vehículos y peatones.
What is a filling station?
A filling station is a facility where vehicles can obtain petrol, diesel or other fuels and may also offer additional services for drivers and passengers.
How is a filling station indicated on the road?
Many countries use a service or information sign with a fuel-pump symbol to indicate a filling station. The exact design and meaning of the sign vary between countries.
What should you watch for when entering a filling station?
Reduce your speed, follow the designated entrance and traffic direction and watch carefully for vehicles, pedestrians and people moving around the fuel pumps.
96. Código de circulación
Un código de circulación es un conjunto de leyes y normas que regulan cómo se utilizan las vías públicas. Establece reglas para conductores, ciclistas, peatones y otros usuarios y abarca materias como prioridad, velocidad, adelantamiento, estacionamiento, semáforos, señales y marcas viales.
Los códigos difieren entre países y a veces entre regiones. Se espera que todo usuario conozca y respete las normas aplicables donde circula, incluso cuando sean distintas de las de su país de origen.
What is a road code?
A road code is the body of traffic rules and regulations governing how road users must behave on public roads.
What does a road code regulate?
A road code can regulate subjects such as priority, speed, overtaking, turning, parking, traffic signals, road signs and road markings, as well as the responsibilities of different road users.
Are road codes the same in every country?
No. Although many traffic rules and signs are similar internationally, each country establishes its own traffic legislation and may apply different rules, signs, speed limits and requirements.
97. Doble sentido
Doble sentido significa que los vehículos pueden circular en direcciones opuestas por la misma carretera o calzada. Las corrientes opuestas pueden estar separadas mediante marcas, una mediana o, en carreteras estrechas, no tener separación física.
Los conductores deben mantenerse en el lado exigido por las normas locales, ser conscientes del tráfico de frente y tener especial cuidado al adelantar, girar o atravesar tramos estrechos.
What is two-way traffic?
Two-way traffic means that vehicles may travel in both directions along the same road or carriageway.
How are opposing traffic directions separated?
They may be separated by centre lines, traffic lanes, a median or another physical divider. On some roads, opposing traffic may share an undivided carriageway.
Why should you take extra care on a two-way road?
Vehicles may approach from the opposite direction, so drivers should maintain a safe position and take particular care when overtaking, turning or passing through narrow sections.
98. Carril de adelantamiento
Un carril de adelantamiento es un carril utilizado principalmente para adelantar a vehículos más lentos que circulan en la misma dirección. En carreteras con varios carriles por sentido, suele ser el carril más alejado del lado utilizado para la circulación normal.
En países con circulación por la derecha suele estar a la izquierda; con circulación por la izquierda, normalmente a la derecha. Los conductores deben volver al carril normal después de adelantar cuando lo exijan las normas locales.
What is a passing lane?
A passing lane is a lane used primarily to overtake slower vehicles travelling in the same direction.
Which side is the passing lane on?
It depends on the country's driving side. In countries with right-hand traffic it is generally the left lane, while in countries with left-hand traffic it is generally the right lane.
Can you remain in the passing lane after overtaking?
The exact rules vary between countries, but drivers are commonly expected to return to the normal travel lane after completing an overtake when it is safe and required.
99. Canaleta de la calle
Una canaleta de la calle es un canal estrecho junto al borde de una carretera o calle que recoge agua de lluvia y la conduce hacia desagües u otros sistemas. Suele situarse entre la calzada y el bordillo y puede ser de hormigón, adoquines o formar parte de la superficie.
Es principalmente un elemento de drenaje y no un carril de tráfico. Los usuarios deben tener cuidado porque puede contener agua, residuos, aberturas de desagüe o superficies irregulares.
What is a street gutter?
A street gutter is a drainage channel along the edge of a road that collects rainwater and directs it toward drains or another drainage system.
Is a street gutter a traffic lane?
Normally, no. A gutter is primarily part of the road's drainage system and is not intended to function as a normal traffic lane.
Why should cyclists take care near street gutters?
Gutters may contain water, leaves, debris, drain covers or uneven surfaces, which can reduce grip or make cycling less stable.
100. Residuos en la calzada
Los residuos en la calzada son objetos, materiales o sustancias que se encuentran o han caído sobre la carretera y pueden interferir con el tráfico. Ejemplos incluyen piezas de vehículos, carga perdida, piedras, ramas, cristales, basura y materiales derramados.
Pueden crear un peligro grave para conductores, ciclistas y otros usuarios. Los conductores deben observar la vía, reducir la velocidad cuando sea necesario y evitar maniobras bruscas al pasar de forma segura junto a un obstáculo.
What is road debris?
Road debris is any object, material or substance lying on the road that may obstruct traffic or create a hazard.
What are common examples of road debris?
Examples include lost cargo, vehicle parts, stones, branches, litter, broken glass and spilled materials.
What should you do when you see debris on the road?
Reduce speed when necessary, maintain control of your vehicle and avoid the debris only when you can do so safely. Avoid sudden braking or steering that could endanger other road users.

Normas de tráfico
Estados Unidos