Accurate and reliable positioning of vehicles is a decisive factor for many Intelligent Transportation System (ITS) applications. Under the cooperative environment, the eco-driving at specific scenarios, like intersections, requires vehicle motion state information, which can be provided by Global Navigation Satellite System (GNSS) with an integrity monitoring capability. In order to provide effective integrity information to the vehicles for different purposes, the “local integrity” concept is adopted in this paper to build the integrity model for the close spaced areas. The integrity monitoring solution using a Weighted Least Square method and an effective User Equivalent Range Error (UERE) variance strategy is presented. Results from experiments using a multi-receiver platform illustrate the feasibility of establishing integrity models with GNSS measurements within specific time slots. The presented solution is with great potential in enhancing quality of road-side-aided GNSS positioning under a connected architecture and enabling many cooperative systems.