Motorways and Dual Carriageways: Do They Follow the Same Traffic Rules?

Designed for higher speeds than conventional roads, motorways and dual carriageways share very similar characteristics, with both directions of traffic separated by medians and almost identical traffic rules.

Motorways and dual carriageways are the most frequented and safest types of roads, but high speeds require drivers to adhere to rules and maintain maximum concentration to anticipate potential risks.

In Spain, there are 15,500 kilometres of motorways and dual carriageways, which account for 80% of all annual kilometres travelled and about 25% of all road fatalities and serious injuries: in 2023, 345 people died and 964 were seriously injured in accidents on these roads.

A motorway is a high-capacity road with separate carriageways for each direction of traffic, as defined by the DGT's Road Safety and Traffic magazine. It has controlled exclusive access, meaning entry from adjacent properties is not possible. Additionally, it may be a toll road, requiring a variable fee depending on the type of vehicle.

According to Occident, a dual carriageway is also a high-capacity road with separate carriageways for each direction, but it does not meet the same user and access requirements as a motorway. Moreover, its use is free of charge.

Common features include separate carriageways for each direction of traffic, divided by a median. Pedestrians are prohibited from accessing and using motorways and dual carriageways under any circumstances. According to the DGT, in 2023, there were 57 pedestrian fatalities and 47 hospitalisations due to accidents on motorways and dual carriageways, including drivers who exited their vehicles in emergencies.

Generally, the maximum speed limit is 120 km/h for cars and motorcycles. Adhering to the maximum speed is crucial. In 2023, there were 135 fatalities and nearly 400 serious injuries from road departures on motorways and dual carriageways, a type of accident directly linked to speeding and distractions: at 120 km/h, the maximum legal limit for cars and motorcycles among other vehicles, up to 150 metres may be needed to stop the vehicle. Buses and trucks have lower limits (100 and 90 km/h respectively). Mopeds, vehicles for people with reduced mobility, and animal-drawn vehicles are prohibited as they do not reach adequate speeds. Cyclists, banned from motorways, may use the hard shoulders of dual carriageways when no alternative exists.

Regarding other traffic rules, the minimum speed is noteworthy. It is 60 km/h on motorways and dual carriageways, so in an emergency requiring speeds below this, the driver must exit at the nearest exit.

Motorways are specifically designed and constructed as high-speed roads, with wide curves and straight alignments. Dual carriageways are often the result of converting conventional roads, so they may have tighter curves and less uniform alignments.

Motorways have fully controlled access, with clearly marked and separated entry and exit points. They do not have direct access to adjacent properties. Meanwhile, dual carriageways may have limited access to adjacent properties via service roads, and in some cases, may have level crossings.

Traffic flows in the right lane, changing only to overtake. The DGT emphasises this rule. It is essential to follow this rule on dual carriageways and motorways: drive in the rightmost lane and use others for overtaking. This could prevent many dangerous situations caused by unnecessary lane changes or overtaking on the right. Front-side collisions on motorways and dual carriageways, typical of such manoeuvres, resulted in 21 fatalities and 108 serious injuries in 2023.

Maintaining a safe distance is important due to the high speeds. Drivers should adapt to visibility conditions, reducing speed in rain, ice, fog, and wind.

It is prohibited to change direction, reverse, and stop in non-designated areas. To exit, use the deceleration lane, signalling again with the indicator and starting to brake once in the lane.

Vehicles on motorways and dual carriageways have priority over those merging. However, the rule also requires facilitating merging whenever possible and safe, to ensure safer and smoother traffic flow, by moving to the left lane if unoccupied or simply easing off the accelerator for a few seconds.

Not respecting the safe distance is one of the most important and least observed driving rules, as seen by the separation spaces between vehicles on the roads.

At 120 km/h, two to three seconds of separation between vehicles is necessary—counting 1001, 1002, 1003... relative to a fixed point—to drive without collision risk if, for example, a sudden stop or traffic jam occurs. Rear-end and multiple collisions, often caused by inadequate vehicle separation, resulted in 78 deaths and 273 serious injuries on motorways and dual carriageways in 2023.