Pavement rut depth has a direct influence on traffic safety and it gives a good idea about the general road condition. Ruts generally appear due to the wear and weak load bearing capacity of the road structure. If ruts have appeared due to one of those reasons then water run-off is hindered and aquaplaning may occur. Ruts may also cause the loss of control over vehicle in case of slippery road. The road owner must keep a close eye on rut development.
The limit values of rut depth are described as follows:
|Pavement condition||Characteristics (traffic safety and impact on the road user)||Rut depth limits (mm)|
|Very good||Pavement has no ruts.||< 5|
|Good||No ruts can be observed in the pavement and there is no impact on road users.||5 – 10|
|Fair||Ruts in the pavement can be observed. When it rains water accumulates in the ruts. Road users start to search for best trajectory. Ruts should be eliminated within 1 to 3 years.||10 – 20|
|Poor||Ruts can clearly be seen in the pavement, driving speed as well as trajectory are influenced. When it rains, a lot of water accumulates in ruts and aquaplaning may occur. Ruts should be eliminated.||20 – 30|
|Very poor||Ruts can clearly be seen in the pavement, driving speed as well as trajectory and traffic safety are influenced. Ruts affect traffic safety both in rain and in dry conditions. Ruts should be eliminated immediately.||> 30|
In order to ensure road safety, changes in this parameter are to be regularly observed and if required, proper preventive measures are to be taken.
The ViaPPS (Pavement Profile Scanner) device has been used for rutting measurements since 2014. The device also measures crossfall and curve radius. Comparison measurements are conducted yearly before the measurement period.