Latvian low volume roads and particular – their pavements shows serious problems in form of cracking, rutting, other deformations and which finally leads to weak serviceability and short lifetime of the road structure. In many cases these problems has been associated with heavy goods transport, overloaded vehicles and their impact. To find the role of heavy loads, and in particular - timber haulage transport, on road pavement deformations and evaluate their prevention possibilities, as well as to investigate the efficiency of freight transport, and establish conditions that will allow to do it, a study is carried out in Riga Technical university in cooperation with Latvian State Forests SC. As option for load impact reducing, the Central Tire Inflate system (CTI), installed on the test car, is being checked. The research methodology is based on deflection measurements with LWD together with dielectric constant measurements in a road structure using percometer. Measurements are taken in the various pavement structure layers in different depths, during full-scale loading and in different moisture/temperature conditions. Increase of the contact surface is established using the CTI, which was installed on the test car. An advisable intensity and load for heavy traffic according to road conditions will be set during the study.