Shenzhen–Zhongshan 24-kilometre bridge–tunnel link with two artificial islands

Driving above the sea, vanishing into a tunnel without warning, then emerging onto an artificial island with a technology museum - in southern China, that is now part of everyday life.

A new motorway connection between the megacities of Shenzhen and Zhongshan has recently opened - and it feels closer to science fiction than a typical trunk road. Over 24 kilometres, China has fused a record-setting bridge section, an enormous undersea tunnel and two artificial islands into a single corridor, complete with an exhibition centre focused on high-tech civil engineering.

A new pinch point solved in China’s booming bay area

The bay region around Guangdong, Hong Kong and Macao is among the world’s most important economic zones. Manufacturing, logistics and research all depend on fast links, and until recently drivers often needed nearly two hours to get from Shenzhen to Zhongshan, typically via congested routes and ferry crossings.

With the new connection along the G2518 route, the journey time drops to about 30 minutes. The toll costs the equivalent of around €10. For commuters, haulage firms and delivery services, that translates into a dramatic reduction in time - and, by extension, real savings.

“The route links two mega-cities in half an hour, where previously half a working day was lost in traffic jams.”

A superstructure of steel, concrete and artificial islands

From an engineering perspective, this is a package of multiple mega-projects - each of which would normally attract headlines on its own - brought together into one transport scheme.

• Total length: 24 kilometres above and below the sea
• Elements: two huge bridges, one undersea tunnel, two artificial islands
• Travel time between Shenzhen and Zhongshan: about 30 minutes
• Average daily traffic: around 86,000 vehicles
• Peaks: more than 181,000 vehicles per day during travel periods

One bridge segment is particularly eye-catching: an exceptionally long suspension-bridge section with steel pylons that holds several world records. To make it possible, engineers poured what is described as the largest concrete anchorage foundation to date - around 344,000 cubic metres. Scale like this is required to protect the structure against typhoons, waves and extreme loads.

That ambition is reflected in the wind testing: the system reportedly withstood gusts of almost 84 metres per second - speeds at which conventional structures would typically already be suffering serious damage.

The undersea tunnel: eight lanes in an extra-wide tube

The tunnel beneath the sea bay is at least as striking. It runs underground for almost seven kilometres and is described as the world’s widest immersed tube tunnel built using a steel-and-concrete method.

At 46 metres wide, the tunnel can accommodate up to eight lanes. That allows multiple lanes in each direction to operate at the same time without capacity being exhausted too quickly. To drivers, it presents as a broad, brightly lit tube - but the systems behind the scenes are highly complex.

Robots as tunnel police

To keep traffic safe in this sensitive section, the entire tube is monitored by a digital web of sensors and machines. According to the project information, operators rely on 14 specialised robots that patrol inside the tunnel and continuously analyse data.

These machines can immediately flag unusual situations - such as broken-down vehicles, obstacles or smoke. In an emergency, they can help organise an evacuation before responders arrive on site. Systems like these can significantly cut reaction times in the event of an incident.

“The smoke extraction system works around 42 percent more efficiently than conventional installations and is intended to deliver valuable minutes in the event of a fire.”

In long tunnels, every minute matters. Up-to-date smoke control, ventilation and emergency exits reduce the risk of panic or people being trapped by smoke. China is using this project to trial new standards that could later be applied elsewhere.

A traffic giant with a built-in tourist attraction

Since the opening, it has been clear how strongly the region has been waiting for this shortcut. On average, around 86,000 cars a day use the new link. During public holidays and major travel periods, the figures jump sharply: more than 181,000 trips have already been recorded within 24 hours.

An express coach system running the route has proved especially popular, offering an alternative to driving. Nearly three million passengers have already used it. The knock-on effect is tangible: hotels, restaurants and excursion destinations across the area report noticeable gains, and during China’s National Day holiday, tourism activity rose by more than 100 percent.

An island shaped like a mythical creature

One unusual detail sits right on the route itself. The western of the two artificial islands is not only a technical hub but also a cultural stop. It hosts a new science museum with roughly 2,200 square metres of exhibition space.

The museum focuses above all on marine engineering, high technology and climate risks along coastlines. Visitors can learn how undersea tunnels are constructed, what forces pull at bridges over the sea, and how computer technology helps keep such structures safe over the long term.

Even the island’s outline is intentional. From the air, it resembles the “Kunpeng”, a legendary figure from Chinese mythology that can transform from a gigantic fish into a vast bird. The symbolism is clear: what once looked like an impassable sea suddenly becomes a direct leap from city to city.

What the project means for China - and the rest of the world

For China, this new connection is more than a quicker route. It underlines how strongly the government is pushing to tie its coastal metropolises more tightly together. Infrastructure of this kind supports entire industrial clusters: semiconductor plants in Shenzhen, factories around Zhongshan, logistics centres and ports can mesh more effectively.

At the same time, the scheme sends a message beyond China. Any country planning to cross large straits, fjords or wide bays will be watching hybrid solutions like this closely: combinations of bridges, immersed tunnels and artificial islands tailored to local coastal geography.

Total route length	24 kilometres
Structural elements	2 bridges, 1 tunnel, 2 artificial islands
Travel time between the cities	approx. 30 minutes
Average daily traffic	86,000 vehicles
Maximum tunnel width	46 metres, 8 lanes
Monitoring	14 patrol robots in real-time operation
Toll	around €10

Opportunities, risks and unresolved questions

Mega-projects like this create major opportunities: less congestion, shorter supply chains, and new jobs in construction, maintenance and tourism. Commutes shrink, while businesses gain more predictable planning. The added museum layer also gives the whole development a friendlier public face, drawing school groups and engineering enthusiasts.

At the same time, questions arise about environmental impacts. Artificial islands can alter currents, marine habitats and bird routes. Building tunnels and bridges offshore stresses ecosystems, particularly during the construction phase. Supporters argue that modern methods reduce these risks; critics call for long-term monitoring and stricter standards.

Another issue is dependence on digital control. Robots, sensors and automated safety systems make the facility more efficient, but they also introduce new vulnerabilities. In a worst-case scenario, cyberattacks or software faults could have wider consequences than traditional mechanical failures. For that reason, operators are investing heavily in redundancy and emergency plans that can still function without high-tech systems.

For other countries, the Shenzhen–Zhongshan link provides a real-world testbed. Engineering consultancies and transport planners can observe how this bridge–tunnel–island mix performs day to day: how durable are materials in saltwater? How do traffic flows behave in this configuration? And how well do drivers cope with the rapid sequence of bridge, tunnel and island?

What is certain is that this new superstructure off Guangdong’s coast shows how far highly complex infrastructure has already advanced - and how close science-fiction scenarios now sit to the daily drive to work.