We derive a simple one-dimensional model for the description of fire events in long vehicle tunnels, which is based on appropriate low-Mach number asymptotics as well as on averaging procedure along the cross-section of a tunnel. Turbulent effects are modelled using a phenomenological model. Numerical simulations based on a standard finite-difference method show the ability of the new model to describe fires in tunnels at least qualitatively. Copyright (C) 2002 John Wiley Sons, Ltd.