  We introduce the minor-closed, dual-closed class of multi-path matroids. We
give a polynomial-time algorithm for computing the Tutte polynomial of a
multi-path matroid, we describe their basis activities, and we prove some basic
structural properties. Key elements of this work are two complementary
perspectives we develop for these matroids: on the one hand, multi-path
matroids are transversal matroids that have special types of presentations; on
the other hand, the bases of multi-path matroids can be viewed as sets of
lattice paths in certain planar diagrams.
