Traffic disruption modelling with mode shift in multi-modal networks
Dong Zhao1, Adriana-Simona Mih˘
ait¸˘
a1, Yuming Ou1, Sajjad Shafiei2, Hanna Grzybowska3,
Kai Qin2, Gary Tan4, Mo Li5and Hussein Dia2
Abstract— A multi-modal transport system is acknowledged
to have robust failure tolerance and can effectively relieve urban
congestion issues. However, estimating the impact of disruptions
across multi-transport modes is a challenging problem due to
a dis-aggregated modelling approach applied to only individual
modes at a time. To fill this gap, this paper proposes a new
integrated modelling framework for a multi-modal traffic state
estimation and evaluation of the disruption impact across all
modes under various traffic conditions. First, we propose an
iterative trip assignment model to elucidate the association
between travel demand and travel behaviour, including a
multi-modal origin-to-destination estimation for private and
public transport. Secondly, we provide a practical multi-modal
travel demand re-adjustment that takes the mode shift of the
affected travellers into consideration. The pros and cons of
the mode shift strategy are showcased via several scenario-
based transport simulating experiments. The results show that
a well-balanced mode shift with flexible routing and early
announcements of detours so that travellers can plan ahead
can significantly benefit all travellers by a delay time reduction
of 46%, while a stable route assignment maintains a higher
average traffic flow and the inactive mode-route choice help
relief density under the traffic disruptions.
Index Terms— multi-modal transport, traffic states estima-
tion, disruption modelling, incident impact analysis, mode shift
I. INTRODUCTION
A. Background and motivation
Resilient cities have recently embraced a fully-connected
multi-modal transport network that gives travellers more
freedom when choosing when, where and how to travel.
However, multi-modal urban environments are also vulner-
able due to the lack of tolerance against an ever-growing
population, an expanding travel demand, a high private
car ownership, deficient transport design, inadequate traffic
control and flawed travelling or driving behaviour [1].
To improve the efficiency of the transport system at a large
scale, the encouragement of a travel behaviour change and
active mode shift is an encouraging option studied recently
[2]. Many other research studies reinforce this initiative by
providing substantial evidence via data-driven, or simulation-
based approaches [3], [4], [5]. The data-driven approaches
capture the real traffic behaviour before and after disrup-
tions, and some applications are used in programs such as:
INPHORMM, TAPESTRY or Travel Smart [6]. Other early
1University of Technology Sydney, Ultimo, NSW 2007, Australia. Cor-
responding authors contact: Dong.Zhao@student.uts.edu.au
2Swinburne University of Technology, Hawthorn, VIC 3122, Australia
3Data61, CSIRO, Eveleigh, NSW 2015, Australia
4National University of Singapore, Singapore
5Nanyang Technological University (NTU), Singapore
studies revealed the value of public transport by investigating
the change of traffic states (e.g. section flows, traffic volumes
or travel times) and proposed an entire public transport
service removal when massive public transport disruptions
occur or when service is suspended [7], [8]. Few studies
that consider a simulation approach mention that the change
in the level of congestion before and after the removal
of public transport services would clarify the significance
of public transport [9]. More recently, the unprecedented
COVID-19 pandemic has heavily modified the travel demand
and provided evidence with regards to the impact of traffic
demand across all mode shifts in a city [10].
Challenges: All previous studies solve the mode choice
problem before departing, and most publications provide
modelling methods from a macroscopic or a mesoscopic
level based on a statical analysis. There is little research
into investigating the benefits of an active mode shift from a
dynamic microscopic perspective and its impact when traffic
disruptions occur. A significant gap is present due to the lack
of data regarding the impacted demand under incidents and
active mode shifts. Some studies rely on surveys or a stated
preference obtained ahead of trips to obtain the number of
impacted travellers or the number of mode and route shift
[11], [12]. However, we emphasise identifying the impacted
origin-to-destination (OD) trips affected by disruptions in a
simulating model, and the change of mode and route choice
that leads to a demand change is employed for evaluating
the impact on network performance in our work.
Apart from the lack of data, quantifying the impact of
disruptions is also a major challenge; some research studies
have analysed the change of trip-based mean delay, mean
speed [13] or travel time [9]. However, such indicators can
hardly differentiate the impact from the general traffic (e.g.
recurrent congestion) or from traffic control strategies. To
address this issue, we work across several indicators versus
baseline conditions in order to evaluate the efficiency of the
proposed ones.
Another major challenge of dynamically simulating the
mode shift is the lack of dynamic demand data and the
method of integrating the OD estimation across different
transport modes in order to identify the impacted trips. Most
previous research studies only consider a single-mode [14],
while some research studies model car-based transportation
versus public transportation differently [15]. Extensive ev-
idence considers the OD estimation from a total genera-
tion and attraction data based on the gravity model. This
method has been largely developed with the improvement of
mathematical, analytical and computational skills. However,
arXiv:2210.06115v1 [physics.soc-ph] 12 Oct 2022