95678 - Road Traffic and Circulation Engineering M

Learning outcomes

With the acquisition of the credits the student is provided with principles, methodologies and operational tools for the analysis, simulation, control and monitoring of traffic flows in transport systems. He also acquires the necessary knowledge for the analysis and optimization of the performance of the elements of a transport network, with special regard to the organization and management of traffic in road and rail transport systems.

Course contents

General concepts and definitions:

- Course outline
- The transport supply sub-system in the general framework of transport system engineering
- Traffic flow theory: general principles
- Concept and evaluation of Level Of Service (LOS)

Uninterrupted traffic flow modeling:

- Fundamental variables and macroscopic, steady-state flow models (Greenhields, Greenberg, Northwestern Underwood, Newell)
- Measurement of flow variables, methods and technologies
- Capacity in ideal conditions
- LOS of a freeway section
- Continuous flow models and shock waves, LWR model, higher-order models.
- Microscopic traffic flow models (car-following models, GM model, IDM, Gipp's model).

Basic principles and applications of queuing theory:

- Basic elements of a queue system, theoretical fundamentals
- Poisson single or multiple servant queues: MM1 and MMn
- Non-Poisson queues: MG1, MD1
- Examples and applications.

Signalized intersections:

- Basic definitions: Traffic light cycle and phases, Lane Groups; Saturation Flow.
- Real Saturation Flow estimation
- Capacity, Saturation degree and flow ratio of a lane group
- Delay and LOS of a signalized intersection: Webster, Doherty, Robertson-Whiting, HCM methods.
- Webster and HCM methods for cycle length optimization and phase design
- Yellow plus all-red time estimation
- Traffic light coordination

Unsignalized Intersections:

- Type of intersections; allowed maneuvers and priority rules, rank of a maneuver.
- Definition and practical estimation of critical-gap and follow-up-time.
- Critical volume, potential and actual capacity of each maneuver.
- LOS delay and queue length estimation.

Railway circulation and capacity:

- Structural and functional characteristics of the railway system
- Speed and braking characteristics of trains
- Rail networks: lines and nodes (stations)
- Traffic safety: detection and control equipment
- On-line and station circulation regimes
- Estimation of line capacity: Lehner curves; UIC and RFI methods for line capacity calculation
- Capacity of a railway node: Potthoff method
- The SCMT system
- High Speed Rail: General features; ERTMS - ETCS operating levels; AV/AC management

Readings/Bibliography

Slides and lecture notes

Teaching methods

Frontal lectures, exercises, in-depth seminars.

Assessment methods

Written exams (available time: 2:30 hours) consisting of numerical exercises, open questions, multiple choice questions.

Office hours

See the website of Luca Mantecchini