21 research outputs found
Assessing the Demand Vulnerability of Equilibrium Traffic Networks via Network Aggregation
Shared Space Modeling Based on Social Forces and Distance Potential Field
Urban design is moving towards space sharing in order to increase the
community texture and safety of street surroundings. However, there is a need
for a simulation tool capable of representing future shared space schemes to help
judging the designs under which shared space design is a suitable alternative to
traditional street designs. This paper presents a microscopic mathematical model
that is used a traffic simulation tool capable to represem main behaviors of pedestrians and cars in any shared space layout. This is achieved by generating a route
map which helps agents to find the shortest path towards their target destinations
on the strategic level. On the operational level, the Social Force Model (SFM)
is used and extended for a mixed traffic to produce feasible trajectories. The trajectory results are presented to give a face-validation of the functionality of the
shared space simulation model
Emergency Door Capacity: Influence of Door Width, Population Composition and Stress Level
For the new version of the Dutch design guidelines for buildings, a threshold value for the capacity of emergency doors needs to be set. Innovative largescale laboratory experiments have been performed to investigate the capacity of emergency doors during evacuation conditions. This paper focuses in particular on the relation between capacity and the independent variables doorway width, population composition, stress level and presence of an open door. It turned out that only the experiment with the widest doorway (275 cm) resulted in a capacity lower than the capacity from the current design guidelines (2.25 P/m/s). The average observed capacities are for all widths lowest for the lowest stress level and highest for the highest stress level. The population with a greater part of children has the highest capacity (on average 3.31 P/m/s). This is mainly due to the smaller physical size of children compared to adults and elderly, which makes it possible that more children can pass a door at the same time than adults. The lowest capacity (on average 2.02 P/m/s) is found for the experiment with 5% disabled participants. The presence of a door opened in the escape direction in an angle of 90º for a doorway of 85 cm results in a 20% capacity reduction compared to the reference experiment. The open door does not physically narrow the doorway, but it leads to interactions between participants reducing their speed and the corresponding outflow.Transport and PlanningCivil Engineering and Geoscience
Macroscopic Fundamental Diagram for Train Platforms
The macroscopic fundamental diagram (MFD) relates the flow, density and speed of an entire network. So far, the MFD has been mostly applied to cases where pedestrians and vehicles were aiming to reach their destinations as fast as possible. However, pedestrian facilities involve different behaviours. Especially in train stations, travellers spend more time waiting than walking. Moreover, complex passenger flows (i.e. flows in different directions moving to stairs and escalators distributed over the platform) may occur on the platform, due to passengers. In this paper we show that passenger flows on platforms can be described by an MFD
A novel data-driven algorithm for the automated detection of unexpectedly high traffic flow in uncongested traffic states
We present an algorithm to identify days that exhibit the seemingly paradoxical behaviour of high traffic flow and, simultaneously, a striking absence of traffic jams. We introduce the notion of high-performance days to refer to these days. The developed algorithm consists of three steps: step 1, based on the fundamental diagram (i.e. an empirical relation between the traffic flow and traffic density), we estimate the critical speed by using robust regression as a tool for labelling congested and uncongested data points; step 2, based on this labelling of the data, the breakdown probability can be estimated (i.e. the probability that the average speed drops below the critical speed); step 3, we identify unperturbed moments (i.e. moments when a breakdown is expected, but does not occur) and subsequently identify the high-performance days based on the number of unperturbed moments. Identifying high-performance days could be a building block in the quest for traffic jam reduction; using more detailed data one might be able to identify specific characteristics of high-performance days. The algorithm is applied to a case study featuring the highly congested A15 motorway in the Netherlands