Winter maintenance

The Finnish Transport Infrastructure Agency and the Centres for Economic Development, Transport and the Environment ensure that traffic routes are operable throughout the year.

Winter maintenance policies define the principles by which roads are maintained during winter and their operability is ensured. The guidelines for winter maintenance were updated in 2018 and the new guidelines for contracts have entered into force for the period 2019–2023.

Winter conditions

Snow ploughing

In winter road maintenance, snow is usually first ploughed and then antiskid treatment is applied. The busiest roads are ploughed first. The aim is that on busy roads and on pedestrian or cycling routes there should not be no more than a few centimetres of snow. Once the snowfall comes to an end, the snow is removed from main roads within two to three hours and from pedestrian and cycling routes within four hours. Low-traffic roads may occasionally have up to ten centimetres of snow, and the snow should be ploughed within six hours.

Antiskid treatment

The weather service facilitates forecasting of when the road surface will freeze. On busy roads, antiskid treatment involves salting, while on other roads gritting or roughening is used instead. Antiskid treatment of busy roads is normally carried out in advance, and at the latest within 2 to 3 hours of the first observations of the slipperiness. Sufficient traction is ensured for pedestrian and cycling routes, and particularly for morning traffic. For roads in lower maintenance categories, the aim is to apply antiskid treatment within 6 to 8 hours of observing the slipperiness, but during the most difficult weather conditions, mild slippery conditions may last for longer than this. 

When the quality requirements based on the new winter maintenance guidelines entered into force for tendered contracts from autumn 2019 onwards, antiskid treatment of lower class roads was accelerated, being carried out now within 5 to 7 hours. The quality requirements for antiskid treatment of medium-traffic roads will also be tightened, and the same quality requirement will apply over the coming years.

Learn more about antiskid treatment

To view the up-to-date winter maintenance situation, visit the Traffic Situation website: https://liikennetilanne.tmfg.fi/

Winter maintenance categories

The importance, traffic volume and composition of the road determine the service level required for road maintenance. Since not all roads can be maintained immediately while still keeping costs at a reasonable level, the roads are classified using different maintenance categories. As of 1 January 2019, over 11,000 kilometres of roads were either moved to a higher winter maintenance category or had their level of winter maintenance increased in some other way.

Maintenance category Ise

(1,523 km: 2% of road length, 31% of traffic, 28% of heavy traffic)

The road is mainly uncovered. The aim is always to prevent slipperiness in advance, but when the weather changes, some slightly slippery conditions may occur. Even during long periods of subzero temperatures, when salting is not possible, the road surface may be icy in places. The measures are scheduled so that they hinder the traffic as little as possible.

Maintenance category Is

(7,484 km: 10% of road length, 37% of traffic, 42% of heavy traffic)

The road is mainly uncovered. The aim is to maintain good traction, but when the weather changes, some slightly slippery conditions may occur. In Central and Northern Finland and during colder periods in the southern part of the country, there may be some thin longitudinal layers of packed snow that do not have any significant effect on driving conditions. The term ‘packed snow’ refers to a packed ridge of snow or ice on the road. During long period of subzero temperatures, when salting is not possible, the road surface may be icy in places. As a rule, slipperiness is prevented by taking proactive measures.

Maintenance category I

(519 km: 1% of road length, 2% of traffic, 2% of heavy traffic)

The road is uncovered most of the time. The aim is to maintain good traction, but when the weather changes, some slightly slippery conditions may occur. There may occasionally be low and narrow lines of packed snow located between the carriageways and between the driving ruts. During long period of subzero temperatures, when salting is not possible, the road surface may be icy in places. The aim is to prevent problematic slippery conditions by carrying out proactive antiskid treatment.

Maintenance category Ib

(13,517 km: 17% of road length, 18% of traffic, 18% of heavy traffic)

The road receives fairly high-level maintenance. Antiskid treatment is mainly done by salting, but salt usage is lower than in the higher maintenance categories. Depending on the volume of traffic and weather, the road surface is either partly exposed and partly covered with packed snow ridges or, at other times, entirely covered by snow. The tendering process will involve a transition to the use of operating methods that will reduce the quantities of packed snow.

The road usually has good winter conditions, except during the most problematic weather. Some slippery conditions may occur during subzero temperatures. The ruts and surface of the packed snow are levelled as much as possible.

Winter maintenance category Ic 

(1685 km: 2% of road length, 2% of traffic, 1% of heavy traffic)

The road is usually partly or completely covered in packed snow. Salt is normally used only in exceptional cases or when particularly difficult road conditions are forecast. However, salt can be used particularly in the autumn to maintain safe traffic conditions. With the exception of problem situations, the road has good winter conditions. Although traction is not good at all points, it is sufficiently good to offer safe driving providing that the road users take account of the prevailing conditions. The ruts and surface of the packed snow are levelled as much as possible. For the most part, antiskid treatment involves point and line gritting and sufficient roughening of the packed snow.

Maintenance category II 

(15,113 km: 19% of road length, 7% of traffic, 5% of heavy traffic)

The surface of the road is mostly covered with packed snow and may be furrowed in places. In normal situations, the road has sufficient friction and smoothness for moderate traffic. The intersection areas, hills and curves are gritted to ensure safe conditions for normal traffic.

Road surfaces are roughened, and during the most problematic road conditions they are gritted completely. In difficult weather conditions, such as during a sudden rise in temperature or immediately after snowfall, caution is required from all road users.

Maintenance category III 

(38,111 km: 49% of road length, 4% of traffic, 4% of heavy traffic)

The road surface is covered in packed snow most of the time and in places there may also be ruts. The quality level is mostly the same as on category II roads, but snow ploughing and antiskid treatment may take up to two hours longer to be applied. When the weather changes, the road conditions can be problematic for several hours, which means that extra caution must be taken when driving.

Division of the road network into different winter maintenance categories

 

Map of winter road maintenance categories

The map works best when it is opened on its own page: Show a larger map.