How to add normal vehicle rather than intelligent connect vehicle in Veins? In Veins5.1, it seems like every vehicle should be a node and send message with each other. How can I add normal vehicles which will not communicate with other vehicles in simulation?
If you just want some random vehicles to be "dumb" vehicles, you can set the penetrationRate parameter of TraCIScenarioManager to a value smaller than its default, 1.0. If you set this value to, e.g., 0.1, only 10% of your vehicles will be "intelligent" vehicles. The remaining 90% will not even be simulated in OMNeT++.
If you are looking for more control over which vehicles are "dumb" and which vehicles are "intelligent", I would suggest using different OMNeT++ module types for "dumb" and for "intelligent" vehicles. In addition to the standard Car.ned module you could, for example, provide an alternative DumbCar.ned which cannot communicate at all. You can then use the TraCIScenarioManager parameter moduleType to configure which SUMO vehicle types are mapped onto which OMNeT++ module types. More documentation on how to use this parameter is contained in the source code.