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Plans for the Lahti southern ring road complete

A team of consultants headed by Sito completed its work on a plan for the Lahti southern ring road in the summer. Once completed, the ring road will reduce accidents and improve the flow of traffic along highway 12 considerably. The consultants found the work both rewarding and challenging.

Photo: Kujala interchange from the west (© Sito)

A total of 50 consultants from Sito and Ramboll Finland Oy were involved in the exciting task of designing the new Lahti southern ring road from the end of 2013 until the summer of 2015. The project was led by Sito’s Director for Roads Rauno Tuominen. The project has been one of the most fascinating of his career: “I could sum it up by saying that coming up with a cost-effective solution in such difficult terrain in the middle of a built-up area was very challenging!”

Rewarding interaction

Rane21_200x220Rauno Tuominen’s favorite aspects of the project were successful interaction and dialog with stakeholders and local residents. “Interaction during the project was both timely and executed using the right channels. The entire team was left with an extremely positive view of the process, and I believe that the local residents would agree,” he says. Cooperation with the local Center for Economic Development, Transport and the Environment and local authorities was also both transparent and constructive.

Modern regional development and road projects take stakeholders and local residents into consideration much better than a few decades ago, when this kind of interaction was still in its infancy. A lot of progress has been made since the stiff information events, flip chart presentations and non-negotiable plans of the early days. According to Rauno Tuominen, a wide range of inclusive methods have been introduced since then. Local residents are made aware of proposals at an early stage to ensure that they really know what is going to happen. This is designed to make them feel that they have a say and that their opinions will be listened to, understood and taken into consideration. The project was BIM-based from start to finish. This was immensely helpful for encouraging dialog, as proposals could be visualized for the public.

“Local residents often have excellent ideas and viable suggestions. Today, plans can and will be revised if there is good reason to do so. If we cannot incorporate a suggestion, we can explain why. Everyone is left feeling more satisfied with the process,” Rauno Tuominen explains.

With everything settled at the planning stage, there are generally fewer delays at the implementation stage.

Technical challenges

Hava_05_Luhdanjoki_silta_lev500Designing the Lahti southern ring road was also technically challenging. The terrain in the area is not the easiest to work with. The road runs in an area where groundwater accumulates. The watertight Laune groundwater reserve needed to be taken into consideration. The road will incorporate two tunnels: a half-kilometer concrete tunnel at Patomäki and a one-kilometer rock/concrete tunnel at Liipola. There will be a total of 28 new bridges, approximately 13 kilometers of road and five new interchanges to build. More than 5.4 kilometers of noise barriers will need to be constructed in residential areas. Conceptual drawing of the Luhdanjoki river valley from the south.

Difficult starting point

Highway 12 is a key part of the Salpausselkä corridor and a part of the nationwide TEN-T transport network created by the European Commission’s decision. It is one of two main road connections for international traffic to the eastern border crossings and an important transportation route for industry and business. Between approximately 1 300 and 2 300 trucks use the route every weekday.

Highway 12 runs through a heavily built-up urban area in Hollola and Lahti. It therefore also has an important role in the regional traffic network.

Between 13 000 and 35 000 vehicles on average use the highway every day, and the four-lane urban section has a speed limit of between 50 and 70 kilometers per hour. Traffic lights at intersections slow down long-distance deliveries.

The biggest problem, however, is that approximately 22 accidents resulting in personal injury take place along the roads that form highway 12 every year, of which at least one accident per year is fatal. The stretch of road is deemed the most dangerous within the region governed by the Uusimaa Center for Economic Development, Transport and the Environment.

A worthwhile effort

The road plan drawn up by the team led by Rauno Tuominen promises fundamental changes to the situation. Journey times will be reduced by approximately five minutes and by even more during rush hour. Road traffic deaths will drop by approximately 27 and accidents resulting in personal injury by approximately 34%. The ring road will also remove between 11 000 and 15 000 vehicles per day from Lahti’s internal road network. The new design even reduces risks to groundwater.

The cost estimate for the project is approximately EUR 222.5 million. Hollola and Lahti have already signed letters of intent concerning the division of costs with the Finnish Government, and if funding can be secured, works could begin as soon as 2017. The final decision on the fate of the project rests with the Parliament of Finland. The works are estimated to take three years.

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