**5. Conclusions and future perspectives**

The paper illustrates a unified framework which embeds a simultaneous traffic control strategy and the automated vehicle control. In particular the traffic control strategy is composed by two sub models: one is referred to the centralised traffic management the other one is characterised by the link metering strategy; regarding the vehicle control, the speed optimisation procedure based on Green Light Optimal Speed Advisory (GLOSA) has been applied in particular with reference to the next single junction approached by the vehicles (S-GLOSA). A microscopic traffic flow modelling has been adopted and all models were run in a SUMO simulation environment.

The integrated framework was then tested on a real case study consisting of a highly congested sub-network in the city centre of Naples (Italy). The network layout is represented by one diversion node and two alternative paths connecting the same origin - destination pair.

In order to evaluate the effectiveness of the proposed framework, three scenarios were tested: the first was only based on a centralised traffic control procedure [TC] that was further analysed considering the bi-level mono-criterion implementation and the multi-criteria approach; the second one was based on speed guidance optimisation [S-GLOSA] and the third was based on the combination of both sub-models the multi-criteria traffic control and the speed optimisation [TCMULTI & S-GLOSA]. Finally, the framework effectiveness was evaluated in terms of within-day dynamics with respect to the travel times and queue length performance indices.

Three main considerations have arisen: the first one is about the TC strategy and in particular it was tested that multi-criteria optimisation outperforms the mono-criterion approach; the second one refers to the comparison between TCMULTI and S-GLOSA therefore it is verified that S-GLOSA provides worse performances than the TCMULTI method; finally the combination between TCMULTI and S-GLOSA provide as expected best results.

Regarding future research perspectives, some preliminary modelling considerations may be summarised. First of all, the authors would like to test the proposed framework on different networks characterised by more complex topologies. Secondly, the sensitivity at different penetration rates of CAV must be analysed. Thirdly, further refinements are needed for the implementation of the S-GLOSA strategy and, for completeness, in future researches the environmental impact will be also analysed.

Finally some further technological and operational perspectives may be discussed. The situation described and analysed in the chapter has shown the benefit of the cooperation among infrastructures and vehicles control. It is worth noting that this situation is one of the possible results that technological development on one side, and normative evolution on the other, will enable in next years. For example, the implementation of S-GLOSA (or even MS-GLOSA) in urban environments will be strongly affected by the communication technologies used, with an evident advantage for this use case of the Automotive LTE with respect of Dedicated Short Range Communication (DSRC). In summary, for this and many other reasons, the concrete future implementation of cooperative scenarios has some kinds of uncertainty, but this last observation make even probably more meaningful the kind of experiments discussed here.
