Detailed Traffic Plans

Road safety, pedestrian mobility, traffic optimization, new traffic solutions, safety at bus stops, exceptional maintenance for road signs, street furniture refurbishment: all these are dealt by the PPT (Piani Particolareggiati del Traffico - Detailed Traffic Plans).

The Plans do not have a great financial commitment, they oversee short-term construction sites and they intervene when there are records of historical and certified data. The main effects are a lower accident rate, smooth traffic flow, a decrease in air and noise pollution and more liveable and enhanced areas.

About 70 traffic projects are drafted every year on a functionally/preliminary level, as well as 250 projects for moving or installing bus stops. Furthermore, according to PGTU, detailed traffic plans for each neighborhood has been drafted and within these 80 projects have been carried out in the past 13 years (out of the 200 submitted) for about 200 interventions completed. Speaking of road safety, the interventions brought to a decrease of more than 50% of road accidents - in some specific cases up to 100%.

Drafting plans: the process

Plans are drafted according to what the city “needs”, both in terms of “urgent” matters and aspirations for the future.

Appropriate security and safety standards for critical intersections, road links and pedestrian and cycle lanes had to be ensured. It was also necessary to make sure to create more liveable areas for citizens and to ensure a better quality of life in the city.

This process was based on citizens' requests and on reports made by local administrators; on this basis, technicians and planners started working on a series of interventions matching the PGTU projects. More than 40 technicians - traffic engineers, urban architects, transportation planners, traffic modelling technicians, environment specialists and so on - were involved, plus local administrators and the supervisors of different Council Departments who worked on cycle lanes, noise and air pollution, green area projects, architectural barriers, Urban Parking Programs etc.

Traders and citizens associations were constantly involved, to offer their contribution promoting the “philosophy” of the interventions being designed and later developed on their neighborhoods; moreThese plans involved the entire territory: more than 200 interventions were carried out in 15 municipal boroughs.

The articulation of the project started with a preliminary phase of analysis of challenges, an initial phase of proposals to review the traffic scheme and create a functional classification of the entire road network, then the decision and proposal of priority interventions and finally planning detailed interventions. This process continued with the approval and implementation phase, that started with a series of services conferences, followed by the approval of the Municipal Council and the town council actions that allocated funds to carry out these works. Finally, the definitive projects were drawn up and the construction sites were open.

Analysis of the current situation and challenges

The first phase consisted in collecting available data on accident rates and traffic flow for the area involved, the analysis and elaboration of the collected information, also through a development of road network simulating models, to identify challenges or, even better, to write a list of challenges and to give each one a level of importance, in order to establish an intervention priority scale.

“Challenge” is a general and synthetic word that can be referred to the need to review the manoeuvres at a crossroad, improve the visibility when approaching the crossroad, guarantee safety on pedestrian lanes, protect parking spaces and make sure they are used correctly, intervene to improve the traffic flow on main roads and preserve environmental-friendly areas etc.

The first and most important indicator of possible challenges was the high rate of accidents, considering the traffic flow on the streets, intersections or more in general the area involved. The analysis of these challenges was conducted together with experts from the City council and the municipal police, that contributed in finding matters to focus on during the following phases of the projects, based on their experience.

Study of the mobility scheme and review of the functional classification of the street

The first intervention was the review of the classification of the streets: there is a hierarchy for streets, depending on their geometrical characteristics and the role they have. The first hierarchical classification was drawn up by the General Urban Traffic Plan and they referred to it when reviewing it in relation to the objective function of the streets involved or recently added functions, following changes made to the traffic scheme, the development of new attractors or new inter-zone relations, or changes in the geometrical characteristics of the streets.

Detailed plans proposed, when necessary, to review the functional classification of the road network, including important routes that have a fundamental role today; on the other hand some streets seemed to have lost their importance, for these it was proposed a new classification among local streets.

A review of the functional classification of the road network was only possible by studying the entire traffic scheme (main roads and local roads): the target was to concretely associate the function to the classification of each road. The traffic scheme proposed had to, on one hand that the crossing flow (i.e. that did not originate and were not leading to the area that they were studying) affected only the main road network, on the other hand the local road network had to guarantee accessibility to environmental-friendly areas, parts of the territory located inside the main road network.

Integral part of this detailed plan, connected to the functional reorganisation of main streets and local roads, is the drafting of a “Plan for indication and routing signs”, so that traffic flows, that need to drive through the area, have a clearer view of the routes to take. 

Detailed plan

In close and consequential relation to the proposals made for the integration of a functional classification for the road network and a possible revision of the traffic scheme, a list of interventions to carry out was agreed on and drawn up, integrating the results of the first analysis of challenges to tackle.

When carrying out this detailed planning, the first general principle was to guarantee a functional main road network, that is to say to give necessary standards to main streets in order to effectively fulfil that role: if the traffic scheme revision ensured that crossing flow only used main roads, this planning has to guarantee necessary services in terms of capacity and fluidity.

For the main road network, a series of interventions were considered to maintain a smooth flow and at the same time improving safety of all pedestrian lanes and crossings, where there’s a high concentration of both pedestrians and vehicles.

The accesses and crossings have thus been concentrated as much as possible along the main roads and the areas for making U-turns have been rationalised. The traffic capacity of the intersections had been increased, both through new sets of traffic lights and by optimising the capacity of the tailback areas. Lastly, adequate visibility has been guaranteed in the vicinity of the intersections.

For what concerns the local road network on the other hand, residents were heard and their requests accepted, to protect and expand pedestrian areas, carrying out interventions to moderate speed, destroying architectonic barriers, making sure that residential areas were accessible and last but not least, carrying out interventions for a requalification of streets and squares that are neighbourhoods’ main attractions, proposing simple interventions of urban renewal or great interventions of requalification.

Even for this phase the contribution of local technicians was substantial. They periodically examined the proposed solutions, suggested adjustments and improvements even for what concerned details, they also suggested planners what materials and furniture to use.

Synthesis of the Plan and its approval

Once the preliminary projects of all interventions identified by the detailed plan were drawn up, a synthesis document was drafted for each portion of the involved territory.

The Plan synthesis was approved first at the Services Conference, where all the involved institutions and organisations took part: AMA, park cleaners, public and private transport services and all the technical bodies of the districts involved. During this conference, planners were called to summarise the essence and purpose of the interventions proposed, but also to prove the effectiveness of these interventions through complementary studies carried out with the help of micro-macro simulation technics.

Planners illustrated the plans also during City Council meetings, in which the interventions were not only approved but the course of action was shared by all political parties.

Even during the process of approval, planners showed more and more confidence in the plan proposals, that was later considered common heritage by all operators that intervened.

Finally, with a decree issued by the City Council, the plan and the interventions proposed, were approved by the Central Administration that, at the same time, allocated the necessary funds for the execution, definitive/executive planning and implementation.

The planning process found concrete implementation with the drawing up of definitive and executive projects for the interventions and their execution on the streets. The process ends with an investigation carried out on the streets to check the effectiveness of these interventions by not only technicians and planners but also and more importantly by citizens, who are the users and receivers of these plans.