Ring I: User safety is the first priority in Mestaritunneli's technology


c.100 000 cars
Ring Road I is Finland's busiest highway and an important transport hub, carrying c. 100 000 cars every day

530 meters
Mestaritunneli consists of two parallel,
four-lane tunnels, connected by safety tunnels



  • The starting point was to manage the heavy traffic flow and ensure safe conditions for tunnel users
  • The aim was also to increase the attractiveness of the Leppävaara area in Espoo, and to visually unify structure with the urban area.
Tunnel entrance
Caverion experts in the tunnel


  • The renewal of the technical systems of the master tunnel was carried out in 2008-2012. We took care of the design and implementation of the tunnel's HVAC system, telematics, and automation. The value of the contract was approximately EUR 11 million.
  • In all tunnel technology, user safety was a priority and the technology was designed to protect tunnel users. The tunnel was kept open during maintenance because stopping the traffic flow could cause safety problems for tunnel users. We had traffic control in place to restrict access to the tunnel in the event of congestion. During maintenance, we kept only a few lanes open in the tunnel and used signs, traffic lights, and obstacles to control traffic.
  • Tunnel ventilation and smoke extraction are handled by ventilation ducts that remove exhaust gases from the tunnels. Ground-mounted piping systems divert the water that accumulates in the car lanes.
  • The electrical systems in Mestaritunneli consist of a certified power supply, backup power, UPS, fire alarms, audio and telecommunications systems, access control, and security systems.
  • Traffic control systems, traffic lights, signals, and traffic lights form the telematics systems of the tunnel.
  • Automation consists of a HVAC system and traffic control automation.

How does telematics make tunnels safer? Read our expert blog (in Finnish)


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