Road condition assessment
The condition of roads is monitored by taking measurements and inventories. Roads are classified according to their condition into one of five different categories.
Road condition is monitored by taking measurements and inventories
Service level measurements (PTM) measure a number of features that describe the condition of the road surface. The most important features for the road user are the depth of the ruts and the evenness of the surface. The depth of the ruts is measured in millimetres. The interpretation of the evenness figures is not as straightforward as that of the rut figures. The key figures derived from the measurements indicate in particular the condition of the road network that sees greater traffic use.
On low-traffic roads, the condition of the road surface is mapped out by visual surveys. These surface damage surveys are based on the assessments of trained surveyors. Using these assessments, the repair needs are then determined.
These measurements and inventories are not carried out on every road every year. Service level measurements are carried out on the main road network every 1–2 years on average and on the low-traffic road network every 3–4 years. Surface damage surveys are carried out approximately every 3 years.
Development of ruts can be predicted
The condition of the entire road network is measured or inventoried at regular intervals. The key figures from the measurements and inventories are stored in the road register. By using the data in this register, planners of road surfacing work have access to detailed information on road surface conditions.
Rutting can also be predicted fairly reliably from the key figures on road conditions. The forecasts are based on the rut depth measurements from previous years and the grooving speeds calculated from these.
Road condition classification
What makes a road to be in good or bad condition?
A road can be considered to be in poor condition if the traffic using the carriageway has to change its position in the lane because of the ruts or road damage, or if the road is so uneven that it makes road use less comfortable.
A paved road is considered to still be in good condition if it does not have any ruts, large depressions or dislocations, and if the cracks are narrow or well patched. Even if the road is in good condition, the colour may be faded due to its old age.
Roads are classified according to their condition
Paved roads are divided into five categories according to their condition. The classification process is based on measurement and inventory data, traffic volumes and speed limits. On roads with high traffic volumes, the category is largely determined by the rut depth. On low-traffic roads, on the other hand, the damage inventories play an important role.
The road condition category serves as a tool for planners of road surfacing work. The category is also used to monitor the condition of Finnish roads and their development over time.
Road condition classification
5. Very good: Equivalent to a new road. No maintenance needs.
4. Good: The condition of the road is good, even if there are signs of normal wear and tear. No maintenance needs.
3. Satisfactory: Satisfactory condition. Usually there is a need for increased monitoring of the road’s condition, and there may be a need for some individual maintenance measures.
2. Poor: Repair work is needed. This is the right time for carrying out maintenance and renovation work to ensure sustainable road maintenance.
1. Very bad: A poor road whose condition is no longer acceptable. It generates extra costs for both the road operator and road users.