Transportation engineering | EPFL Graph Search

Transportation engineering or transport engineering is the application of technology and scientific principles to the planning, functional design, operation and management of facilities for any mode of transportation in order to provide for the safe, efficient, rapid, comfortable, convenient, economical, and environmentally compatible movement of people and goods transport. The planning aspects of transportation engineering relate to elements of urban planning, and involve technical forecasting decisions and political factors. Technical forecasting of passenger travel usually involves an urban transportation planning model, requiring the estimation of trip generation (number of purposeful trips), trip distribution (destination choice, where the traveler is going), mode choice (mode that is being taken), and route assignment (the streets or routes that are being used). More sophisticated forecasting can include other aspects of traveler decisions, including auto ownership, trip cha

El espesor del camino, visto a través de dos proyectos de transporte en Argelia

Aniss Mouad Mezoued

Lane and pathway thickness: definition essay based on two case studies of Algerian transport projects. Planning and transport engineering have for a long time considered pathways and lanes as continuous lines connecting a point A to a point B. In terms of transport, those points are considered as places located in the space-time, while the link between them is considered as a "no-place" that should be reduced in terms of travel time or distance.This transport and mobility representation does not take into consideration the reality of pathways' territorial thickness. The latter relates on the first hand to the multiplicity of activities, temporalities and representations that are overlaid on each other like a palimpsest. On the other hand, thinking in terms of lines is quite reductive. It denies the fact that a line has a thickness that includes a part of the crossed territory on both sides of the line itself. This paper will contribute first to define the territorial thickness of pathways or lanes. It will distinguish between vertical and horizontal thickness. Then, the text will explore methods to identify and characterize it. Finally, through two case studies in Algeria, we will show how transport planning at local as well as regional scales denies this thickness and disturbs lanes and pathways systems.

2018

The influence of trip length distribution on urban traffic in network-level models

Mikhail Murashkin

Modeling urban traffic on the level of network is a wide research area oriented to the development of ITS. In this thesis properties of models based on MFD (Macroscopic Fundamental Diagram) are studied. The idea behind MFD is to say that the state of the traffic inside an urban zone is fully determined by its accumulation (the number of traveling vehicles) and that the dynamics of accumulation is caused by the inflow of vehicles (flow of vehicles that enter the zone or start their trips from inside). Nowadays, two different philosophies of modeling dynamics of accumulation exist in the literature. The first one (outflow-MFD) postulates that the outflow of vehicles depends on accumulation. The second one (speed-MFD) postulates that the space-mean speed of vehicles depends on accumulation. The second philosophy already has strong empirical support based on observations of traffic inside many big (kilometer-scale) urban areas around the world. Thus, different speed-MFD models are of great scientific interest. The thesis is mainly devoted to the comparison of so-called PL model (which assumes the existence of both speed-MFD and outflow-MFD) and TB model (which assumes the equality of speeds of vehicles and explicitly assumes the existence of trip length distribution). It was shown that PL model cannot accurately describe the dynamics of accumulation after the jump of inflow. In this case TB model is more preferable. Moreover, it was proven that PL model is a specific case of TB model for the exponential trip length distribution. This makes TB model more attractive than PL model for the practical usage. TB model can be formulated mathematically either as integral equation or nonlocal PDE. Thus, the main drawback of TB model that can be an obstacle in practice is its computational complexity. In this thesis it was proposed to approximate TB model with a simpler model which does not require precise information about the trip length distribution. This so-called M model operates with only the mean and the standard deviation of distribution and has a form of ODE. The analytical comparison between PL, TB and M models proved that M model is much closer to TB model than PL model in the case of constant speed-MFD. The more realistic case of decreasing speed-MFD was studied through the numerical tests and also showed the same effect. Thus, the main conclusion of the study is that M model has practical potential as an elegant and computationally cheap approximation of TB model. Also, given that in the case of constant speed TB model is a type of LTI system, it can be expected that M model might be useful for a wide range of problems that are not related to transportation. However, in this thesis the conclusion about the small difference between M and TB models was made for the inflows that are typical for the transportation field. More precisely, only peak hour shaped (smooth and with small jumps) functions were studied. Despite the simple form of M model it was found that there exists even more simple ODE approximation of TB model. This so-called

\alpha

model works quite well for both smooth and jumping inflows except the case of a short period of time following the jump of inflow. Thus, it might be another good alternative to TB model. The main advantage of

\alpha

model in the case of realistic speed-MFD function is its convex formulation which allows

\alpha

model to be efficiently used inside optimization frameworks.

EPFL2021

Pedestrian Stop and Go Forecasting with Hybrid Feature Fusion

Alexandre Massoud Alahi, Dongxu Guo, Taylor Ferdinand Mordan

Forecasting pedestrians' future motions is essential for autonomous driving systems to safely navigate in urban areas. However, existing prediction algorithms often overly rely on past observed trajectories and tend to fail around abrupt dynamic changes, such as when pedestrians suddenly start or stop walking. We suggest that predicting these highly non-linear transitions should form a core component to improve the robustness of motion prediction algorithms. In this paper, we introduce the new task of pedestrian stop and go forecasting. Considering the lack of suitable existing datasets for it, we release TRANS, a benchmark for explicitly studying the stop and go behaviors of pedestrians in urban traffic. We build it from several existing datasets annotated with pedestrians' walking motions, in order to have various scenarios and behaviors. We also propose a novel hybrid model that leverages pedestrian-specific and scene features from several modalities, both video sequences and high-level attributes, and gradually fuses them to integrate multiple levels of context. We evaluate our model and several baselines on TRANS, and set a new benchmark for the community to work on pedestrian stop and go forecasting.

2022

The influence of trip length distribution on urban traffic in network-level models

Mikhail Murashkin

\alpha

\alpha

model in the case of realistic speed-MFD function is its convex formulation which allows

\alpha

model to be efficiently used inside optimization frameworks.

EPFL2021