1,720,984 research outputs found
A new microscopic model for the simulation of shared space schemes
Full text linkShared space is an innovative streetscape design which seeks minimum separation
between vehicle traffic and pedestrians. Urban design is moving towards
space sharing as a means of increasing the community texture of street surroundings.
Its unique features aim to balance priorities and allow cars and pedestrians
to co-exist harmoniously without the need to dictate behaviour. There is, however,
a need for a simulation tool to model future shared space schemes and to
help judge if they might represent suitable alternatives to traditional street layouts.
This thesis presents a microscopic mathematical model to simulate pedestrians
and 4-wheeled motorised vehicles in shared space schemes. The complete development
of the model is addressed: mathematical formulation of three interrelated
layers based on the Social Force Model (SFM), software implementation,
calibration and validation using the case studies from New Road (Brighton) and
Exhibition Road (London).
Microscopic pedestrian, vehicle and mixed traffic models are reviewed and evaluated
with respect to their ability to reproduce behavioural phenomena, resulting
in the SFM being adopted as the most suitable basis for this thesis. The behavioural patterns of shared space users are analysed to identify specific manoeuvres
that need consideration. These patterns are realised in a three-layer
model: The first layer introduces the flood fill algorithm to define intermediate
destinations for agent’s path around obstacles to the final destination. The second
layer explains how the SFM is modified for pedestrians and vehicles. The third
layer describes conflict avoidance with minimal change of speed and direction.
The new mathematical model is calibrated and validated according to defined
performance indicators using real data from the two case study sites. The results
show that this model is suitable to simulate shared space users but that the physical
parameters depend on how a shared space scheme is realised compared to
the original philosophy. The achievements of this thesis can be beneficial to urban
planners and councils considering the implementation of a new shared space
scheme.Open Acces
Developing and evaluating a coordinated person-based signal control paradigm in a corridor network
No full textConnected Vehicles (CVs) provide both vehicle trajectory data and occupancy information to the junction controller, which make person-based signal controls to be possible by realizing the importance of reducing person delay. This study presents a coordinated person-based signal control algorithm (C-PBC), which has extended a previously developed approach from isolated junctions to multiple junctions. C-PBC incorporates vehicle information that is outside the CV communication range from the adjacent junction. It also updates data inputs for signal optimization algorithms based on formulated different arrival vehicle trajectory situations and coordinated data supplement algorithms. The developed algorithm has been evaluated using simulation with benchmarking signal control methods under a variety of scenarios involving CV penetration rates and predictive horizons. The results indicate that C-PBC is able to significantly improve person delay reduction when compared with fixed time control and vehicle-based control using CV data in 100% CV penetration rate under saturated flow conditions
A hybrid traffic responsive intersection control algorithm using global positioning system and inductive loop data: (paper no 18-02779)
No full textThis paper compares the performance of a traffic responsive intersection controller which combines vehicle Global Positioning System (GPS) data and inductive loop information, to fixed-time, inductive loop, and GPS based controllers. The INRIX Global Traffic Scorecard reports that vehicles spent up to 42% of their travel time in congested traffic in 2016. Inefficient signal timingchoices by isolated intersection controllers contribute to traffic delays, causing severe negative impacts on the economy and environment. Signal timings can be improved using vehicles’ GPS information combined with vehicle flow information from inductive loops to overcome the control action deficit at isolated intersections. This proposed new signal control algorithm is beneficial for traffic engineers and governmental agencies, as optimised traffic flow can reduce fuel consumption and emissions.The proposed traffic responsive Hybrid Vehicle Actuation (HVA) algorithm uses position and heading data from vehicle status broadcasts, and inferred velocity information to determine vehicle queue lengths and detect vehicles passing through the intersection to actuate intersection signal timings. When vehicle broadcast data are unavailable, HVA uses inductive loop data. Microscopic simulations comparing HVA to fixed-time control, inductive Loop Based Vehicle Actuation (Loop-VA) and GPS Based Vehicle Actuation (GPS-VA) on four urban road networks were carried out to see how the proposed HVA algorithm performs compared to existing control strategies. The results show that HVA is an effective alternative to traditional intersection control strategies, offering delay reductions of up to 32% over Loop-VA, for networks with 0 − 100% connected vehicle presence
Traffic responsive intersection control algorithm using GPS data
No full textThis paper reports on the performance of signalised intersection control using vehicle GPS information compared to fixed-time and inductive loop based control. Traffic congestion forecasts estimate an increase of about 60% in 2030. At present, poor choice of signal timings by isolated intersection controllers cause traffic delays that have enormous negative impacts on the economy and environment. Signal timings can be improved by using vehicles' GPS information to overcome the control action deficit at isolated intersections. This new signal control algorithm is beneficial for traffic engineers and governmental agencies, as traffic flow can be optimised and, hence, fuel consumption and emissions decreased. Under the open European Telecommunication Standards Institute (ETSI) Cooperative Awareness Message (CAM) framework, a traffic responsive GPS based vehicle actuation algorithm (GPS-VA) is proposed. GPS-VA uses position and heading data from vehicle status broadcasts, and inferred velocity information to determine vehicle queue lengths and detect vehicles passing through the intersection. The gathered information is then used to actuate intersection signal timings. Microscopic simulations comparing GPS-VA to fixed-time control and inductive loop based vehicle actuation (Loop-VA) on four urban road networks were performed to see how the proposed GPS-VA algorithm performs compared to existing control strategies. The results show that the GPS-VA is an effective alternative to traditional intersection control strategies, offering delay reductions of up to 50% for connected vehicle fleet penetrations above 30%
Developing an open-source platform for the evaluation of intelligent traffic control algorithms
No full textIntersection management is a key component of road transport systems. Envisaging a new age of road transport systems accommodating intelligent, connected, and autonomous vehicles, many novel intersection control algorithms have been proposed in the literature. These algorithms are often implemented using bespoke software and tested over custom built network models because of their complexity and the lack of freely accessible software tools. This in turn makes them difficult to evaluate and benchmark.To solve this issue, in this paper, we present the Traffic Control Test Bed project, the objective of which is to develop an open source microsimulation platform for the evaluation of intersection control algorithms. The platform provides a library of road network models together with an intuitive synthetic road network generator for user-defined layouts. It facilitates and streamlines the parallel execution of simulations. Outputs and performance indicators are monitored and visualised by the platform both during runtime and at post processing stage. We demonstrate the usage of the platform with a case study evaluating two simple signal optimisation methods. As well as being an arena for traffic control algorithms, the open source property of the platform also invites contributions from the wider research community to improve execution validity and efficiency of traffic control systems
Mixed traffic modelling involving pedestrian dynamics for integrated street designs: a review
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