Finite volume schemes for locally constrained conservation laws

This paper is devoted to the numerical analysis of the road traffic model proposed by Colombo and Goatin (J. Differ. Equ. 234(2):654-675, 2007). The model involves a standard conservation law supplemented by a local unilateral constraint on the flux at the point x = 0 (modelling a road light, a toll gate, etc.). We first show that the problem can be interpreted in terms of the theory of conservation laws with discontinuous flux function, as developed by Adimurthi et al. (J. Hyperbolic Differ. Equ. 2(4):783-837, 2005) and Burger et al. (SIAM J. Numer. Anal. 47(3):1684-1712, 2009). We reformulate accordingly the notion of entropy solution introduced by Colombo and Goatin (J. Differ. Equ. 234(2):654-675, 2007), and extend the well-posedness results to the L (a) framework. Then, starting from a general monotone finite volume scheme for the non-constrained conservation law, we produce a simple scheme for the constrained problem and show its convergence. The proof uses a new notion of entropy process solution. Numerical examples modelling a green wave are presented.