The need for roundwood transport capacity vary throughout the year. The need during a period is influenced mainly by the volume transported the period, the number of days during which transport can be carried out, seasonal variations in road conditions and the weight of the roundwood, and the origin of the wood (private forest owners/ forest companies). The need for transport capacity generally increase during the winter and in spring, after thawing. Lack of logging trucks combined with a lack of drivers for these trucks make it hard to hire extra help during periods of increased transport capacity needs. It is also very expensive to keep logging trucks for use only during these periods. In this thesis, two new concepts based on the partial transport by truck tractors have been examined, to find out the possibility for increased performance and flexibility.

Freno AB i Piteå har byggt en Semitrailerdragare baserat på Volkswagen Crafter. De modifikationer som behandlas i detta arbete omfattar Semitrailerns parkeringsbroms, manövreringen av Semitrailerns färdbromsar och det bakre underkörningsskyddet på dragfordonet. Tillverkaren av dragfordonet vill att det ska utredas huruvida dessa ändringar kan ha negativa effekter.En systembeskrivning av parkeringsbromsen gjordes och dess funktion analyserades sedan utifrån kraft- och momentjämvikt. Trailerns parkeringsbroms manövreras via en elektrisk signal ansluten till kontakten för indikatorn på instrumentpanelen. Resultatet jämfördes sedan med de trafikförskrifter som gällde vid fordonets ibruktagande.