  We discuss a class of coupled system of nonlocal balance laws modeling
multilane traffic, with the nonlocality present in both convective and source
terms. The uniqueness and existence of the entropy solution is proven via
doubling of the variables arguments and convergent finite volume
approximations, respectively. The numerical approximations are proven to
converge to the unique entropy solution of the system at the rate $\sqrt{\Delta
t}$. The applicability of the proven theory to a general class of systems of
nonlocal balance laws coupled strongly through the convective part and weakly
through the source part, is also indicated. Numerical simulations illustrating
the theory and the behavior of the entropy solution as the support of the
kernel goes to zero(nonlocal to local limit), are shown.
