This article deals with car-like vehicle location (with submeter accuracy level) using an enhanced map, GPS solutions, odometer and gyroscope measurements. An enhanced map contains vector objects similar to computer aided road construction data, typically clothoids in 2D, for which the projection process (or map-matching) is not explicit and time consuming. So, one proposes a model and an algorithm of bayesian particle filtering that make it possible simultaneous positioning and mapmatching : actually, this model directly considers the map data in the definition of its state vector. Simulation are included in this article as a first proof on concept.