This article attempts to review the multi-scale modeling concept as an adaptive strategy in traffic flow modeling. The central objective of multi-scale model is to describe and predict traffic phenomena (e.g. individual accelerations, queuing) that occur at different scales by switching between different modeling paradigms. Particular emphasis in this paper is placed on resolving inconsistencies that arise in the process of integrating models, which we address by applying the so-called mesoscopic LWR model (Lighthill, Whitham and Richards model (1,2) as the coarse scale model in our framework. The mesoscopic model is fully consistent at the macroscopic scale with the classic LWR model but it does facilitate tracking of individual vehicles. This characteristic makes it possible to combine this model with microscopic models because there essentially is no disaggregation/aggregation process needed. This implies that for example travel infonnation (e.g. destination) can be carried over this model without loss of infonnation. Also vehicle heterogeneity can be incorporated in the mesoscopic model and as a result preserved in the process of switching between models. The paper provides a brief ovetview of mesoscopic LWR model and its solution by the Variational theory. General boundary condition including internal boundaries (e.g. moving bottlenecks) and interfaces between models are analyzed and evaluated. Furthennore, the solution of some cases, in which the stationary and moving bottlenecks interact, is provided. The paper concludes with a case study that demonstrates the integration of microscopic and mesoscopic models in a multi-scale model and investigate the influence of various boundary conditions on traffic features.