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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 traffic 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.

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.

Maintenance category Ise.

Maintenance category Ise

(1,591 km: 2% of road length, 30% of traffic, 28% of heavy traffic)

The road is mainly uncovered. Snow removal starts once snowfall begins. Slipperiness is prevented in advance. The aim is to keep the road always in the condition defined in the quality requirements. The time allocated to snow removal is a couple of hours. When the weather changes, some slightly slippery conditions may occur. During long periods of subzero temperatures, when salting is not possible, the road surface may also be icy in places. Maintenance rounds on maintenance category Ise roads are short, so that busy roads can be quickly maintained to the condition defined in the quality requirements.

Maintenance category Is.

Maintenance category Is.

(7,728 km: 10% of road length, 37% of traffic, 42% of heavy traffic)

The road is mainly uncovered. Snow removal starts soon after snowfall begins. Slipperiness is mainly prevented in advance. When the weather changes, some slightly slippery conditions may occur. During long periods of subzero temperatures, when salting is not possible, the road surface may also be icy in places. The time allocated to snow removal and anti-skid treatment is a couple of hours. Maintenance rounds on maintenance category Is roads are fairly short, so that the maintenance round can be completed in the time allocated.

 

Maintenance category I

Maintenance category I

(184 km: 0.2% of road length, 1% of traffic, 1% 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 periods 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 anti-skid treatment.

The maintenance category will be eliminated in the next few years in connection with maintenance contract tendering. Roads in the maintenance category I will be typically transferred to the category Is or Ib.

Maintenance category Ib.

Maintenance category Ib

(11,962 km: 15% of road length, 17% of traffic, 17% of heavy traffic)

Most of the time, the road is mainly uncovered, but in subzero temperatures, there may occasionally be low and narrow lines of packed snow located between the carriageways and between the driving ruts. The aim is to keep the packed snow thin with the fast removal of loose and packed snow. Anti-skid treatment is mainly done by salting. The aim is to prevent slipperiness in advance. During long periods of subzero temperatures, when salting is not possible, the road surface may be icy in places. Slippery conditions that may occur during subzero temperatures are prevented by gritting, as necessary. The time allocated to snow removal and anti-skid treatment is a few hours.

The contract tendering process will involve a transition to the use of operating methods that ensure that there will be hardly any roads covered entirely with packed snow.

Winter maintenance category Ic.

Winter maintenance category Ic

(3,606 km: 5% of road length, 4% of traffic, 3% of heavy traffic)

The road is usually partly covered with packed snow and sometimes or completely covered with packed snow. The ruts and surface of the packed snow are levelled as much as possible. The road pavement condition and road edge depressions affect the levelness of ploughing. For the most part, anti-skid treatment involves point and line gritting and the roughening of packed snow. In winter conditions, traction is not good at all points, which should be taken into account in driving behaviour. The occurrence of black ice is also prevented by salting. Especially in the autumn before actual winter conditions and in the spring when subzero temperatures occur at night, anti-skid treatment is done by salting. Salting can also be used in anti-skid treatment at other times if the conditions are favourable. The time allocated to snow removal and anti-skid treatment is a few hours. The intensity of snowfall affects the time when ploughing starts.

Maintenance category II.

Maintenance category II

(15,409 km: 20% of road length, 7% of traffic, 5% of heavy traffic)

The surface of the road is mostly covered with packed snow and there may also be ruts in places. It may snow several centimetres before maintenance procedures are started. In the newest contracts, the procedures will be started a little sooner than this in the period between 2 a.m. and 8 p.m. Road surfaces are roughened and the intersection areas, hills and curves are gritted regularly. During the most problematic road conditions, the roads are also gritted completely. The need for gritting is determined according to the conditions. The road network’s ploughing and anti-skid treatment routes are long, which means that they take several hours to drive through.

In normal situations, the road has sufficient friction and smoothness for moderate traffic. 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.

Maintenance category III

(37,422 km: 48% of road length, 4% of traffic, 4% of heavy traffic)

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

Maintenance category K1.

Pedestrian and cycling routes

Maintenance category K1

(3,035 km: 59% of pedestrian or cycling route length)

In winter conditions, pedestrian and cycling routes are mainly covered with packed snow. Anti-skid treatment procedures start within two hours. Slipperiness on pedestrian and cycling routes is prevented by gritting or roughening. There may be a few centimetres of loose snow on pedestrian and cycling routes before maintenance starts routes paths must be ploughed within three hours of the start of maintenance. At night between 10 p.m. and 6 a.m., quality may be lower but the surface of the route must still be safe.

Maintenance category K2.

Maintenance category K2

(2,100 km: 40% of pedestrian or cycling route length)

In winter conditions, pedestrian and cycling routes are mainly covered with packed snow. The quality level is mostly the same as on maintenance category K1 routes, but snow ploughing and anti-skid treatment may take up to one hour longer. At night between 10 p.m. and 7 a.m., quality may be lower but the surface of the route must still be safe.

Maintenance category L

Maintenance category L

(65 km: 1% of pedestrian or cycling route length)

The route-like quality corridors for pedestrians and cycling are located in major urban areas. The requirements for quality corridors are defined on a case-by-case basis so that they are consistent with the cycling route network in the municipalities on the quality corridor and the requirements are in some respects higher than in the maintenance category K1. For instance, the slipperiness of the quality corridor may be prevented by brush salting, the allocated times may be shorter or in the spring, grit may be removed from the quality corridors earlier to promote cycling. Quality corridors may also have night-time quality requirements.

Snowstorm

During snowstorms, the quality requirements are not valid

Maintenance contracts are dimensioned according to normal weather conditions. In the winter, weather conditions may change rapidly, making it very difficult for the maintenance contractor to be responsible for road maintenance according to the quality requirements. During heavy snowfall (10 cm in 4 hours) or during rain of supercooled water, roads fall below the quality requirements quickly after maintenance. In these situations, the quality requirements defined in the maintenance categories are not valid. The contractor will work continuously with all their fleet. Roads will be maintained to their normal condition when conditions return to normal.

Clearing the view at junctions

The safe use of junctions requires a clear view. Near junctions, any snow banks blocking the view are lowered and other obstructions limiting visibility and posing an immediate danger to traffic are removed as soon as possible. Views at junctions are continuously maintained.

The maintenance of views at junctions is not the responsibility of the road maintenance contractor alone: junctions to public roads fall under the responsibility of the road owner, which can be the state, a municipality, a private road cooperative or the owner of the property. 

With regard to snow banks, see also