“It is concluded that it is not viable to implement the reversal of the metrobus at the top of the avenue [da Boavista], instead of the necessary roundabout turn. It is technically necessary and justifiable to use the Boavista roundabout as the turnaround point for the new line,” writes the Sociedade de Transportes Coletivos (STCP) in a letter addressed to the Mayor of Porto, referring to the Metro do Porto tests.
The STCP, the future operator of the system, describes that during the trials, “the vehicle had to invade several adjacent lanes to its dedicated track, requiring the complete interruption of other traffic flows.”
“This fact represents a limitation because the arrangement of the current road does not allow an articulated bus of 18 meters to reverse within the normal lanes without interfering with cross traffic,” it warns.
For the STCP, “what was geometrically feasible in a controlled environment without incidents would become, in everyday operations, a complex task, prone to coordination errors and traffic constraints.”
Thus, the STCP maintains that “the conditions are not met” for the maneuver to be performed “repeatedly and safely in a real context, without any police support, given the negative impact on circulation and the cadence of the service intended to be implemented.”
“The use of the roundabout allows buses to reverse direction in a natural, continuous way integrated into the road scheme, minimizing interference with other traffic,” it notes.
Based on the “technical analysis” from the June 5 tests, the STCP proposes to the mayor, the “transport authority over public road transport operations” in Porto, “that the direction reversal is done by circumventing the Boavista roundabout.”
The option aims to “ensure the reliability and efficiency of the metrobus operation.”
The STCP warns that the recommendation is based “on objective criteria of planning and operation of public road transport, aiming to meet the high frequency of service without compromising urban circulation, not implying any increase in the number of drivers.”
“The solution of reversing the direction at the top of the avenue is unviable for regular operation,” it states.
The system “was designed to offer a high-capacity and regular service, with very frequent circulations, in the order of one vehicle every 4/6 minutes per direction during peak hours.”
This cadence “implies reduced intervals between vehicles, with rigorous schedules synchronized with the traffic light system along the entire route.”
“If each vehicle needed a special prolonged traffic light cycle to reverse direction at the top of the avenue, it would lead to successive delays and idle times incompatible with the four-minute interval between departures,” it describes.
The STCP also warns that reversing direction during regular operation would “drastically reduce the drainage capacity of adjacent lanes” for private vehicles, regular public transport, and pedestrians, “potentially generating long queues and high waiting times for other road users.”
