Abstract
In Finland, road surface friction measurements are an important part of winter maintenance quality control. The maintenance requirements for roads in Finland are based on road maintenance classification. Maintenance requirements are defined in four ways: friction requirement, temperature limit, given allowed response time, and validity period. The Finnish Road Administration (FINNRA) and maintenance contractors use a friction measurement device called C-trip. This is based on a friction measurement method based on deceleration of the measuring vehicle. C-trip has a better price/quality ratio than alternative measurement techniques (the slide-force friction method and the slide friction method).