Helsinki’s underground service tunnel used illegally by drivers as shortcut through city centre

A little-known underground service tunnel beneath central Helsinki is being used by ordinary drivers as an illegal shortcut, despite safety concerns and a formal ban on through traffic, public broadcaster Yle reports.

The 2-kilometre tunnel, built in the 2000s for maintenance and delivery vehicles, runs from Kaisaniemi to Ruoholahti, allowing drivers to bypass the congested area around Helsinki Central Railway Station and Kaivokatu—where car traffic will be permanently restricted in the 2030s. Yle obtained special permission to drive the route, completing the trip in about five minutes.

Around one million vehicles pass through the tunnel annually, according to Mikko Syrjänen, CEO of Helsingin Väylä Oy, the city-owned company that operates it. Roughly 80 percent are authorised trips to underground parking facilities, while the remaining 20 percent consists of permitted service traffic for central businesses—and illegal through traffic by private drivers.

Enforcement is effectively impossible, Syrjänen admitted. “If we installed barriers, it would disrupt legitimate service traffic and make deliveries unworkably slow.” Exact numbers of violators are unknown, but he acknowledged the problem: “Yes, there is through traffic. People commit other offences too.”

The ban stems from safety deficiencies in the tunnel’s older eastern section, built in the 1980s. Unlike the western end—equipped with modern emergency exits—the eastern segment lacks dedicated escape routes, such as separated stairwells or lifts to street level. “In a fire or accident, people need a way out,” Syrjänen said. Current building codes prohibit increased traffic until upgrades are made.

Helsinki aims to expand the tunnel’s use within this decade, pending safety improvements. Reetta Putkonen, the city’s director of traffic and street planning, confirmed plans to add at least one emergency exit at the eastern end “within a few years,” enabling two-way parking access. The push aligns with Helsinki’s broader goal of reducing car traffic in the centre, a priority reflected in the current city strategy.

For now, drivers entering from either end must exit the same way—unless they ignore the ban. As Syrjänen noted, the tunnel’s unofficial appeal is clear: “It’s a fast route. And right now, there’s no way to stop it.”