Managing Kerb Activities To Reduce Congestion

PTV Group collaborated with the International Transport Forum (ITF) to model congestion and operational impacts of new kerb use scenarios related to ride share services in Lisbon’s Central Business District (CBD). Using their traffic modelling and simulation software, PTV Group analysed curb-specific impacts that stem from a growing uptake of ride share services to help public policy define potential reallocation strategies. The results, published in the report “The Shared Use City: Managing the Curb”, show that as ride share adoption increases an overall reduction in traffic delays can be expected, but only when proper management of curb-side activities is implemented.

The report considers the competing activities that occur along city streets and how increased levels of shared mobility, as well as urban logistics and increases in single parcel deliveries, are adding to curb-side congestion. Therefore, the need to manage all competing activities, through efficiently positioned and managed pick up and drop off zones, are key to maintaining smooth traffic flow.

Freer traffic movement and less delays

The findings show that if no dedicated curb space is provided for pick up/drop off, the vehicle flow capacity reduces by up to 50%, due to the effect of double parked ride share vehicles causing congestion. However, the introduction of dedicated pick up/drop off curb-space reduces delays to traffic flow in the Lisbon CBD by up to 20%.

Prioritising the allocation of curb space to ride share activities away from existing car parking spaces could result in lost car parking revenue for the city. However, analysis with the microsimulation tool, PTV Vissim, demonstrates that pick up/drop off spaces have the potential to service over 90 transactions in an hour, compared to Lisbon’s CBD, which has one transaction per space every five hours. Implementing pricing mechanisms is therefore an important aspect to consider, whereby passengers will pay a premium to be picked up or dropped off at busy locations. This helps manage congestion, but also allows cities to recoup losses in on-street parking revenue. Whilst allocating dedicated curb space is not feasible in all urban areas, the study highlights how the effective management of curb space best supports the integration of large scale ride share services on urban streets.

Three-phase analysis

To determine how increased levels of shared mobility services impact curb-side activity and traffic congestion, different consumer ride share adoption scenarios were assessed with and without managed curb side space. Data extracted from the adoption scenarios provided an insight into what transitioning to new mobility services may look like.

The analysis adopted a three-phase modelling solution to ensure a realistic representation of traffic conditions with ride share services. Firstly, ride share trip requests obtained from the Lisbon mobility data was fed into PTV MaaS Modeller, which optimised the dispatching and routing of the vehicle fleet to individual person trip requests. Secondly, PTV Visum was used to simulate background traffic conditions of private vehicle trips. Thirdly, the detailed simulation of curb-side activities, including individual vehicle behaviour and interaction with the background traffic was then carried out with the microsimulation software, PTV Vissim.

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