This system, however, lasted only a few years until closed in 1945, as a result of damage sustained to its infrastructure during World War II.

At the time of its maximum extent (in the 1960s and 1970s), the second system was composed of two circular and four radial lines: Line 42, with an outer terminus in Casalecchio di Reno, was the only one to exit the municipal area; it provided a service that was integrated with the Casalecchio–Vignola railway, until the latter was later on temporarily closed to passenger traffic and reopened in the early 2000s.

[3]: 305  The final closure was of line 41 on 1 June 1982 — a "temporary" withdrawal of trolleybuses for the summer which was made permanent on 16 September 1982.

A ceremonial "inauguration" event took place on 20 April 1990, in connection with a transport conference being held, with one trolleybus of each type running over a short section of the route that was temporarily energised for the occasion.

On 14 October 2002, the second stage of expansion was reached, with the reactivation of the circular lines 32 and 33, following the same routings as in the previous trolleybus system, but with refurbished overhead wiring.

[10] Construction of an extension of line 13 within the San Ruffillo district, from Ponte Savena to Via Pavese, began in 2003, and the new section opened for trolleybuses on 13 September 2007.

The trolleybuses in the current fleet have diesel engines enabling them to operate away from the trolley wires, but only to a limited extent.

[18] The six routes comprising the present Bologna trolleybus system are: Currently, all lines in service are equipped with special devices located on the same remote to transmit a "wire fall or break alarm" resulting in a precautionary tripping of power switches.

It is also planned to raise the line voltage from 650 to 750 V. During Saturdays, Sundays and Public Holidays, the City Council of Bologna has implemented a policy closing Via Ugo Bassi, Via Rizzoli, part of Strada Maggiore and half of Via Indipendenza to regular traffic, with routes 13 and 14 travelling through Via Ugo Bassi (13, 14), Via Rizzoli (13, 14) and Strada Maggiore (14).

[2] The line was initially powered by five electrical substations (Borgo Panigale, Tofane, Avesella, Carducci, Murri).

The work was completed during the first half of 2007, and the extension was opened for service on 13 September 2007,[11] to coincide with the introduction of the new winter schedule.

[13] Along the western half, to Piazza Giovanni XXIII in the Barca district, the old trolleybus wiring was completely renewed, but the support poles were re-used.

In the meantime, the planned line 14 had been extended, by the addition of two branches on the eastern section: 14A (the main line) to the end of Via Due Madonne (depot) and 14C to the end of al Pilastro (as well as a third branch, 14B, for the Roveri industrial area, to operate only in the morning rush hour).

At the time of opening for trolleybuses in 2012, the A branch was also not yet equipped with wiring along its outermost section (of 2.7 km),[22] from Rotonda Paradisi to the terminus, Due Madonne depot, but construction work was under way.

[22] Line 14 is fed by six substations (Barca, Tofane, San Isaia, Carducci, Massarenti, Due Madonne).

[23] Departing from Piazza XX Settembre, near the Bologna bus station and Bologna Centrale railway Station, it terminates in via Pertini in San Lazzaro di Savena; after passing through Via Marconi, Via Ugo Bassi, Via Rizzoli, Strada Maggiore, Via Mazzini, Via Emilia Levante and Via Kennedy (San Lazzaro).

[30] On 24 July 2011, the Italian newspaper Il Fatto Quotidiano reported about various accusations against ATC spa, back then the public transport operator of Bologna, of misusing approximately 17.5 million euros.

[31] These accusations were made by the Gruppo Tutela della Spesa Pubblica financial watchdog, as they claimed that ATC spent those money from the taxes of local citizens for the Civis project instead of depositing them in the city council's revenue department.

The project was to create a better transportation service between Bologna and San Lazzaro di Savena, with some interchanges in the Servizio Ferroviario Metropolitano, back then in its planning stages.

It involved the repavement of several roads in Bologna and San Lazzaro and the improvement of various bus stops to make them accessible to disabled people.

However, it soon became clear that the Civis was unsafe to drive, causing opposition and outright refusal by local drivers to operate it.

In fact, various ATC bus drivers declared that it was too large to pass through certain streets in the city centre (namely Strada Maggiore and Via San Vitale, which are now served by trolleybus routes 14 and 15), and that the driver's seat situated in the centre of the bus did not allow for a lateral view of the roads.

This caused the intervention of a ministerial enquiry by the Ufficio Speciale dei Trasporti a Impianti Fissi (USTIF); which officially declared the Civis unsafe to drive and caused the project to be shelved in 2011[32] A director for the construction of the related infrastructures claimed that ATC and Irisbus insisted to carry out the project despite it being already initially rejected in 2005 due to various technical inconsistencies.

The first stage of the works was carried out between June 2014 and December 2014 in Strada Maggiore and Via Mazzini,[36] causing the diversion of bus routes T1, 14, 19, 25, 27, 101, 106, 916 and 918.

[39] The second phase of the works was criticised and slowed down due to various protests, since the first excavations brought to light an old medieval square and various other archaeological remains.

[40][41][42] Following the last works, the first Iveco Crealis Neo trolleybus was presented to the citizens of Bologna on 2 February 2016, with an inaugural trip departing from Piazza Minghetti[43] along the routing of line 13.