Bologna: satellite navigation to smoothen public bus traffic flows

The Sustainable Mobility Sector of the Bologna Municipality

Bologna is the capital of the Emilia Romagna Region, in central Italy. Within the Land Management Department of the Municipality of Bologna, the Sustainable Mobility Sector is in charge of planning policies and infrastructure interventions to favour sustainable mobility. This involves, among other tasks, monitoring circulation and traffic management measures, including operations carried out by external contractors and/or other city administrations.

The challenge

With a metropolitan population of about a million people, Bologna is served by a network of public buses operated by the publicly-owned company TPER Ltd (Trasporto Passeggeri Emilia-Romagna). Bologna is too small to have an underground transport system, but too large to be crossed with a single bus line. Hence, passengers often need to change buses to move around the city. To promote the use of public buses and ensure the quality of the service, it is therefore important to inform users of the precise arrival times of buses and to guarantee that bus circulation is as smooth as possible.

The satellite solution

For over ten years, Bologna public buses have been equipped with GPS transmitters which regularly communicate their position to a central unit. Today, more than 1 000 buses use the Automatic Vehicle Location (AVL) system. The messages received by the central unit are automatically retransmitted to communicate the expected arrival times at the bus stops.

Moreover, Bologna’ centralised streetlight system adapts to traffic flows in real time, relying on the information provided by the AVL system and by a network of around 1 000 sensors placed under the street pavement, which monitor the number of cars on the street. Two minutes before approaching the traffic lights (detected through the GPS connection), buses send a message to the sensors nearby, allowing the central control unit to adapt the street light phases in real time so as to give priority green light to buses.

The result

Tests performed on a one-kilometre route showed that the system of sensors nearby traffic lights allows to save, in average, one and a half minutes on buses’ travel times. At large, the system ensures a greater regularity of buses arrival times and a considerable decrease of travel times.

Since 2012, the travel times of public buses collected through satellite navigation are made available as open data, allowing for the development of numerous apps to provide arrival times to users directly on their mobile devices. Moreover, the AVM data are used to calculate traffic congestion indexes which, thanks to an agreement with Google, can be visualised on Google Transit to inform users of traffic jams in the Municipality.

The AVM system, today operational on the totality of urban buses circulating in Bologna, will be soon extended to extra-urban bus lines.

“Satellite navigation proved to be a very valuable tool to improve circulation and enhance the use of public transport in Bologna”. Carlo Michelacci, Land Management Department, Sustainable Mobility Sector, Municipality of Bologna