Given a unipotent bundle of smooth manifolds we construct its secondary transfer map and show that this map determines the higher smooth torsion of the bundle. This approach to higher torsion provides a new perspective on some of its properties. In particular it yields in a natural way a formula for torsion of a composition of two bundles.
Bernard Badzioch. Wojciech Dorabiała. "Higher torsion and secondary transfer of unipotent bundles." Geom. Topol. 20 (4) 1807 - 1857, 2016. https://doi.org/10.2140/gt.2016.20.1807