tracie | A minimal , self-hosted event tracking service with SQLite | Runtime Evironment library

you can check if the array key exist using array_key_exists function to prevent the error

Vehicles which leave the simulation in the current simulation step are only removed at the end of the step while traci commands are handled in the beginning. That's why it is currently not possible to do a remove and an add in the same step (not even without traci). Reusing ids is not considered good style in general. The output of `getIDList´ is not reliable here because it lists only the visible vehicles (it also exludes parking vehicles for instance).

After all you might be better off trying to save the simulation state and reload it using simulation.saveState and simulation.loadState.

No, not directly. The route always needs to contain all edges the car is going to drive (except for junction internal edges). You could however call traci.simulation.findRoute beforehand or use traci.vehicle.setTarget if there is only one route (or the desired route is the fastest) to your destination.

You can only remove a vehicle which is already in the network. So maybe your vehicle has not yet departed. The route id is the id of the route either from an XML definition or from an earlier traci.route.add call.