A view from a different kind of city can be interesting.
In Bologna, like in most Italian cities, excessive car use is causing serious air pollution. Most streets are too narrow for fancy transport systems and reserved lanes; parking a car is expensive (in private garages or underground parking lots), or difficult, or illegal, and usually inconveniently distant from one's destination; digging a subway is out of the question.
The main parts of the city center are closed to private traffic (except for residents), with automatic license plate recognition from surveillance cameras. This automated fining system has been kept turned off for years and its startup last year has caused a lot of income for the city but an insufficient reduction of traffic; illegitimate travelers persist and legitimate travelers are still too many.
Public transport consists of buses, of which only a small minority are electrical, and frequent trains to nearby towns. Buses are highly undependable: often very late or missing due to traffic, frequently diverted without warning and with complex variants of each line.
Both suburban trains and buses stop very early in the evening, turning off many potential users. For example, the Bologna-Vignola railway has a stop very near the large basketball court in Casalecchio (about 10 km away); the last train back to Bologna leaves well before the start of evening games or pop concerts.
The only improvements would be brutal restrictions to polluting traffic (but these people vote...) and budget increases to have more buses on the (now less cramped) streets. It is not a matter of low volume or low value traffic: every single car in the city center, either moving or parked, is a problem by itself; with few exceptions it shouldn't be there and its driver is a lazy asshole.
Instead, following the immortal public policy principle of spending money now and solving problems later, a largely redundant "light" rail system between the airport and the central train station is being planned.