Back to Search
Start Over
Macroscopic dynamics and the collapse of urban traffic.
- Source :
- Proceedings of the National Academy of Sciences of the United States of America; 12/11/2018, Vol. 115 Issue 50, p12654-12661, 8p
- Publication Year :
- 2018
-
Abstract
- Stories of mega-jams that last tens of hours or even days appear not only in fiction but also in reality. In this context, it is important to characterize the collapse of the network, defined as the transition from a characteristic travel time to orders of magnitude longer for the same distance traveled. In this multicity study, we unravel this complex phenomenon under various conditions of demand and translate it to the travel time of the individual drivers. First, we start with the current conditions, showing that there is a characteristic time τ that takes a representative group of commuters to arrive at their destinations once their maximum density has been reached. While this time differs from city to city, it can be explained by Γ, defined as the ratio of the vehicle miles traveled to the total vehicle distance the road network can support per hour. Modifying Γ can improve τ and directly inform planning and infrastructure interventions. In this study we focus on measuring the vulnerability of the system by increasing the volume of cars in the network, keeping the road capacity and the empirical spatial dynamics from origins to destinations unchanged. We identify three states of urban traffic, separated by two distinctive transitions. The first one describes the appearance of the first bottlenecks and the second one the collapse of the system. This collapse is marked by a given number of commuters in each city and it is formally characterized by a nonequilibrium phase transition. [ABSTRACT FROM AUTHOR]
- Subjects :
- TRAFFIC congestion
TRAFFIC flow
URBAN transportation
CELL phones
CITIES & towns
ROADS
Subjects
Details
- Language :
- English
- ISSN :
- 00278424
- Volume :
- 115
- Issue :
- 50
- Database :
- Complementary Index
- Journal :
- Proceedings of the National Academy of Sciences of the United States of America
- Publication Type :
- Academic Journal
- Accession number :
- 133553840
- Full Text :
- https://doi.org/10.1073/pnas.1800474115