What is the longest car road tunnel?

Lærdal Tunnel: World's Longest Car Road Tunnel at 24.51 km

longest car road tunnel presents unique challenges for drivers due to its extreme length. Fatigue and air quality are major concerns in such confined spaces. Understanding how engineers addressed these issues helps you prepare for a safe drive through Norways Lærdal Tunnel.

The Longest Road Tunnel in the World

The Lærdal Tunnel in Norway is currently the longest car road tunnel in the world, spanning exactly 24.51 kilometers (15.23 miles). This ^[1] massive engineering feat could be linked to several factors, including Norways mountainous geography and the need for year-round safe transit between major cities. Located on the European Route E16, it connects the municipalities of Lærdal and Aurland, providing a ferry-free and snow-free route between Oslo and Bergen.

Driving through a tunnel this long takes about 20 minutes, which presents unique psychological challenges for motorists. To prevent highway hypnosis and claustrophobia, engineers divided the single-tube tunnel into four distinct sections using three massive mountain caverns. These caverns are illuminated with special blue and yellow lighting designed to mimic the appearance of a sunrise, providing a visual break and keeping drivers alert throughout the journey.

Engineering Marvels and Safety Innovation

The construction of the Lærdal Tunnel cost approximately 1 billion Norwegian kroner^[2] and required the removal of 2.5 million cubic meters of rock. Because driving in a confined space for 24.51 kilometers can be draining, safety was the paramount priority during the design phase. It isnt just about the length - it is about the air you breathe and the mental state of the person behind the wheel.

It was actually the first tunnel in the world to be equipped with its own dedicated air treatment plant. This facility removes dust, soot, and nitrogen dioxide from the tunnel air, ensuring that visibility and air quality remain high even during peak traffic periods. In my experience visiting similar infrastructure projects, the sheer scale of these ventilation systems is often more impressive than the tunnel itself. They are massive, invisible lungs keeping the mountain breathable.

Psychological Lighting and Caverns

Lets be honest: staring at gray concrete walls for 20 minutes is a recipe for disaster. The three caverns serve as breathing spaces. They are 30 meters wide and provide enough space for large trucks to turn around if necessary. The blue light used in these sections is specifically tuned to stimulate wakefulness. But there is a catch - if the light is too bright, it can distract. The balance achieved here is subtle, creating a sense of being outdoors even when you are a kilometer deep under a mountain.

How it Compares to Other Global Tunnels

While the Lærdal holds the top spot for cars, it is often confused with the Gotthard Base Tunnel in Switzerland. However, the Gotthard is a railway tunnel, not a road tunnel, and it is significantly longer at 57 kilometers. In the world of road infrastructure, the competition is heating up, particularly in Asia and Australia, where massive urban and mountain projects have recently been completed.

The WestConnex project in Sydney, Australia, for example, features a 22.4-kilometer tunnel network that opened recently. Meanwhile, the Tianshan Shengli Tunnel in China is expected to reach approximately 22.13 kilometers upon full completion. These ^[4] projects illustrate a global trend: as cities grow and mountain ranges remain obstacles, we are digging deeper and longer than ever before. It is quite a shift from a few decades ago when a 10-kilometer tunnel was considered an extreme outlier.

Top Longest Road Tunnels in the World (2026)

The ranking of the world's longest road tunnels shows a mix of mountain passages and complex urban underground networks.

Lærdal Tunnel (Norway) - Winner

• 24.51 kilometers (15.23 miles)

• Single tube, two-lane mountain tunnel

• Sunrise-simulating lighting caverns

WestConnex (Australia)

• 22.4 kilometers (13.9 miles)

• Urban motorway tunnel network

• Complex underground multi-lane interchanges

Yamate Tunnel (Japan)

• 18.2 kilometers (11.3 miles)

• Urban expressway tunnel

• Deepest point at 30 meters below the surface

The Winter Transit of Erik: From Oslo to Bergen

Erik, a logistics driver in Norway, used to fear the mountain passes in winter. Heavy snow often closed the high roads for days, forcing him to take long detours or wait for expensive, slow ferries that were also subject to weather delays.

He initially tried the old mountain road over the Aurlandsfjellet. He got stuck in a blizzard for six hours, nearly running out of fuel while waiting for a snowplow. The stress of meeting delivery deadlines was becoming unbearable.

He realized that the only sustainable way to move freight year-round was the Lærdal Tunnel. At first, he hated the 'monotony' of the tunnel and felt drowsy halfway through, almost drifting out of his lane once.

Now, Erik uses the blue-lit caverns as markers to stretch his eyes and check his mirrors. The tunnel has reduced his transit time by 80 minutes per trip, and he has successfully completed 400 winter crossings with zero weather-related delays.