A heuristic methodology to tackle the Braess Paradox detecting problem tailored for real road networks

Abstract

Adding a new road to help traffic flow in a congested urban network may at first appear to be a good idea. The Braess Paradox (BP) says, adding new capacity may actually worsen traffic flow. BP does not only call for extra vigilance in expanding a network, it also highlights a question: Does BP exist in existing networks? Literature reveals that BP is rife in real world. This study proposes a methodology to find a set of roads in a real network, whose closure improve traffic flow. It is called the Braess Paradox Detection (BPD) problem. Literature proves that the BPD problem is highly intractable especially in real networks and no efficient method has been introduced. We developed a heuristic methodology based on a Genetic Algorithm to tackle BPD problem. First, a set of likely Braess-tainted roads is identified by simply testing their closure (one-by-one). Secondly, a seraph algorithm is devised to run over the Braess-tainted roads to find a combination whose closure improves traffic flow. In our methodology, the extent of road closure is limited to some certain level to preserve connectivity of the network. The efficiency and applicability of the methodology are demonstrated using the benchmark Hagstrom-Abrams network, and on a network of city of Winnipeg in Canada.

Autonomous vehicles: challenges, opportunities, and future implications for transportation policies

“…In contrast, the cooperative traffic pattern assumes that the vehicles are aware of each other's destinations and routes. It has been shown both theoretically and empirically that the cooperative traffic pattern is more desirable than the non-cooperative traffic pattern, possibly by a factor of 2 [76,77]. It has also been shown that if a number of selfish cars were to collaborate, it may still result in a traffic pattern much superior to the selfish, non-cooperative pattern [78][79][80].…”

Locating inefficient links in a large-scale transportation network

“…The number of genesn in a chromosome should satisfy 1 <n < n. To ensure the significant confidence that every road segment appears at least once in the initial solution, the number of initial chromosomes q was determined by [21]:…”

“…Recently, Braess's paradox was studied in simplified road networks of New York, London and Boston, with only one pair of origin and destination considered [3]. There are few studies on Braess's paradox in practical large-scale transportation networks with realistic transport demand [21].…”

Identifying Achilles-heel roads in real-sized networks

“…The criticalness degree of roads can also be looked at as an index to measure their importance which in turn is utilized in road constructions and their prioritization [6,7]. At the other end of this spectrum, there might be a number of roads whose removal, in fact, improves network performance commonly known as Braess's paradox [8][9][10].…”