Experienced level of service of day-to-day traffic

The objective of the work was to clarify how road users experience the available service level and the relation between service level and the technical instruments used in road maintenance. The road users' experiences were surveyed in three different target areas (Siuntio, Ylaejaervi and Karttula), on separately specified road sections with the help of opinion surveys of road users satisfaction and driving panels. Technical measurements were carried out on the roads at the same time. Road maintenance quality factors concerning daily use of the roads were surveyed in the study, concentrating on the factors that the clients had experienced as the most important in earlier studies and for which there is sufficient data on service level based on technical instruments. The study included winter maintenance, as well as the state of pavement, gravel roads and pedestrian and bicycle ways. The basic hypothesis for the work was that the service level as experienced by road users correlates with the technical instruments, which in its turn would enable a definition of unambiguous values for the level that the road users expect and for the lowest level that they accept. However, the basic hypothesis as such did not hold, i.e., the correlation between satisfaction and measured quality was not especially strong but varied for the different parameters or was almost completely missing. As to winter maintenance, the slipperiness of the road surface correlated best with the service level experienced by the road users. When the friction coefficient exceeds 0.35, road users are relatively satisfied with the winter maintenance level. However, the users are not completely content until the road shows "total summer conditions" in winter. When the friction coefficient is below 0.25, almost all road users are dissatisfied. The change from satisfaction to dissatisfaction occurs between 0.29 and 0.25. As to total satisfaction, this study shows an average for roads very well maintained in winter of 4.5 (main roads), 3.8 (other paved roads) and 2.5 (gravel roads). At present service level, these can be considered to be reachable expected levels for an ideal situation. As to summer maintenance, the measured unevenness reflects best the satisfaction measured for paved road. Measured by IRI (International Roughness Index), the dissatisfaction limit (satisfaction average = 2.5) for regional and connecting roads is approximately 5.6 with a rut depth of approximately 13 cm and a total damaged area of 150 square metres. These results correspond to those obtained in earlier surveys. Gravel road data hardly correlates at all with road user satisfaction. Only the unevenness shows somewhat in the results. Road users seem to be more disturbed by the fact that the road is a gravel road than by its present condition. This report may be found at http://alk.tiehallinto.fi/julkaisut/pdf/3201012-vpaivittaisen_tieliikente.pdf