**3.3 GLOSA (green light optimal speed advisory)**

The Green Light Optimal Speed Advisory (GLOSA) is a Traffic LightS (TLS) time information system for advising drivers by means of using V2I communication. Messages are received by the vehicles on the times of the next TLS. Additionally, an on-board system calculates an ideal approach speed. The convenience on using this system relies on an increasing in safety, reducing the consumption and increasing efficiency of the unction.

In particular, the system adopted provides information about recommended speed level to the vehicle at 300 m from the TLS. If the current speed allows it to cross the intersection without stopping, the vehicle maintains the speed. Otherwise, the speed value allowing it is calculated. If the specific speed value detected is higher or lower than the maximum speed or less than the minimum speed allowed, no communication is provided to the driver and he will stop at the intersection. If the GLOSA is not active, the vehicle stops at signalised junctions; with the presence onboard of the GLOSA the vehicle travels through the same path and stops only 1 time.

It must be clarified that, the research does not focus on the type of communication between infrastructure and vehicle assuming that the messages are always delivered.

Furthermore, the algorithm has been designed aiming to guarantee that the vehicle will be able to cross the unction as soon as possible preferring, therefore, the travel time at fuel consumption or emission. The considered algorithm and the adopted variables are summarised in the following:


The main successive steps of the algorithm are summarised in the following:

	- If red, then the optimisation of the next green intervals is activated;
	- Otherwise, if the phase is green, it is verified if the vehicle speed is able to guarantee the vehicle crossing the section without stopping;
		- a.If yes, the algorithm does nothing
		- b.Otherwise, it is calculated a new green interval for the TS and a set of speeds is calculated (composed by teen values); it is calculated the crossing time and the consistency with the initial value of the green (within green interval) [the optimal value of the speed will guarantee the minimum value of the crossing time].

**155**

**Figure 3.**

*Topology of the tested network.*

*Centralised Traffic Control and Green Light Optimal Speed Advisory Procedure in Mixed…*

The area identified for the case study is the city centre of Naples (regional capital of Campania, southern Italy). This area is characterised by a population

area has a number of inhabitants is around 3,118,000 and the population density is

Two main roads are connected, Via Francesco Caracciolo and Via Riviera di Chiaia, from the West to the East side of the city. Current traffic rules and the connection between these two sides with two concurrent paths are implemented. Two paths are identified, path 1 goes through the Galleria Vittoria, and path 2 is composed of Via Chiatamone, Via Nazario Sauro and Via Acton. The sub-network

The network comprises four signalised junctions, among them traffic signals in

In terms of implementations remarks it must be highlighted that the whole traf-

To optimise the traffic signal decision variables, the rolling horizon approach is adopted combined with a traffic flow prediction model. In particular, the rolling horizon itself is characterised by two terms the roll period (equal to five seconds) and the look ahead period (starting at the end of the roll period and ending at the upper bound of the prediction); in order to further guarantee the consistency with

It must be distinguished that traffic signals in Section 1 and 2 are managed through LM whereas traffic signals in sections 4 and 5 are optimised through NTC. In general, the duration of the cycle length is 110 seconds and the stages 1 2 and 3

Regarding the origin - destination flows (and then the entry exit matrix definition) these have been obtained by combing the results of a macroscopic static traffic assignment procedure (PUMS - NAPOLI) [20] with a traffic counts survey done in 2017; in

fic control procedure operates every control interval (every five minutes).

the traffic flow, traffic information are collected every roll period.

are respectively equal to 19 seconds, 65 seconds, and 26 seconds.

. Also, the total number of internal systematic yearly trips is around

. Moreover, the metropolitan

*DOI: http://dx.doi.org/10.5772/intechopen.95247*

of 978,399 and a population density of 8220 per km<sup>2</sup>

Section 1, 2 and 5 are pedestrian traffic signals.

**4. Application**

**4.1 Case study**

2645 per km2

layout is reported in **Figure 3**.

685,000.

*Centralised Traffic Control and Green Light Optimal Speed Advisory Procedure in Mixed… DOI: http://dx.doi.org/10.5772/intechopen.95247*
