
Amer Said ShalabyUniversity of Toronto | U of T · Department of Civil Engineering
Amer Said Shalaby
PhD
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211
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January 2001 - present
Publications
Publications (211)
The global shift towards sustainable and environmentally friendly transportation options has led to the increasing adoption of electric buses (Ebuses). To optimize the deployment and operational strategies of Ebuses, it is imperative to accurately predict their energy consumption under varying conditions, particularly in cold climates where battery...
The electrification of public transit systems represents a crucial strategy for advancing sustainable urban mobility. Thus, the development of efficient charging infrastructure and the optimization of fleet size emerge as major challenges for transit agencies. Switching from diesel buses to electric buses (Ebuses) will require increasing the fleet...
Accurate prediction of public transit ridership is vital for efficient planning and management of transit in rapidly growing urban areas in Canada. Unexpected increases in passengers can cause overcrowded vehicles, longer boarding times, and service disruptions. Traditional time series models like ARIMA and SARIMA face limitations, particularly in...
Users of the transit system flood social networks daily with messages that contain valuable insights crucial for improving service quality. These posts help transit agencies quickly identify emerging issues. Parsing topics and sentiments is key to gaining comprehensive insights to foster service excellence. However, the volume of messages makes man...
Public transit systems play a crucial role in providing efficient and sustainable transportation options in urban areas. However, these systems face various challenges in meeting commuters' needs. On the other hand, despite the rapid development of Large Language Models (LLMs) worldwide, their integration into transit systems remains relatively une...
The electrification of public transit systems, particularly the adoption of electric buses, stands as a critical strategy in the global pursuit of sustainable urban mobility. Amidst this transition, the establishment of robust charging infrastructure and the optimization of fleet size emerge as pivotal challenges for transit agencies and policymake...
The emerging connected vehicle (CV) technology offers new ways for improving transit service performance in mixed-traffic corridors without having adverse impacts on the general traffic. One promising strategy, CV-enabled driver advisory system (DAS) for transit, aims at advising each bus driver of target travel speed and dwell time values to allow...
The multi-depot vehicle scheduling problem (MDVSP) is a critical planning challenge for transit agencies. We introduce a novel approach to MDVSP by incorporating service reliability through chance-constrained programming (CCP), targeting the pivotal issue of travel time uncertainty and its impact on transit service quality. Our model guarantees ser...
The COVID-19 pandemic has left major shifts in transit usage patterns on systems around the world in its aftermath. Unfortunately, the lack of detailed post-pandemic data on passenger travel habits has limited transit agencies’ ability to respond to trends and leverage new travel markets. The rollout of wireless fidelity (Wi-Fi) services at station...
Time reliability (TR) is a critical factor that affects the efficiency and service quality of the urban rail transit network (URTN). However, previous studies have not incorporated TR into the evaluation of URTN station importance, focusing instead on basic centrality measures. Therefore, this paper proposes a new metric of station-based TR for eva...
On-demand transit (ODT) has been widely piloted in recent years by many transit agencies in response to changing travel behaviour and preferences among people. Some agencies have adopted ODT to replace underperforming bus routes, as part of a continuous service planning process while others incorporated it within network re-design. All these trends...
Typical performance measurements of public transit operations make use of vehicle-based data such as automated vehicle location data or passenger-based data at specific fare collection points. Ideally, the performance of a transit system from a reliability perspective and according to passenger experience should be measured through individual passe...
Transportation systems planning and management rely heavily on Origin-Destination (OD) demand matrices. However, the traditional approach of creating these matrices using household travel survey data is not only time-consuming but also expensive, making it challenging to apply them to detailed and time-sensitive analyses. Automated fare collection...
Transit Signal Priority (TSP) is a broadly used traffic signal control strategy designed for reducing transit delays at signalized intersections. Although recent TSP systems began to consider more objectives, TSPs that addressed transit reliability issues commonly focused on improving schedule adherence and were only able to reduce schedule delays...
Measuring public opinion about the quality of transit services is a key factor in understanding and addressing customer dissatisfaction and increasing customer loyalty and ridership. Sentiment analysis using social media—in particular Twitter—is a relatively cheap and potentially powerful complement to traditional survey methods, which are expensiv...
Typical performance measurements of public transit operations make use of vehicle-based data such as automated vehicle location data, or passenger-based data at specific fare collection points. Ideally, the performance of a transit system from a reliability and passenger experience should be measured through individual passenger journeys. The growi...
Typical performance measurements of public transit operations make use of vehicle-based data such as automated vehicle location data, or passenger-based data at specific fare collection points. Ideally, the performance of a transit system from a reliability and passenger experience should be measured through individual passenger journeys. The growi...
There has been a growing interest in land value capture as a means of funding investments in transport infrastructure (TI), as reported in a vast literature analyzing the relationship between property values and accessibility provided by TI in general and transit specifically. There has, however, been limited research on the role of network-level r...
Mobility‐as‐a‐Service (MaaS) is an emerging business model integrating various travel modes into a single mobility service accessible on demand. Besides the on‐demand mobility services, instant delivery services have increased rapidly and particularly boomed during the coronavirus (COVID‐19) pandemic, requiring online orders to be delivered timely....
Exclusive bus lane (EBL) is one of the most common transit prioritization strategies implemented to improve transit speed. However, one major drawback of implementing EBLs is the associated reduction in road capacity left for other road users. In corridors with EBLs and infrequent bus service, the lanes are underutilized for extended periods of tim...
Ride-hailing (RH) services have been growing rapidly and gaining popularity worldwide. However, many transit agencies are experiencing ridership stagnation or even decline. Understanding the correlation between RH trips and transit ridership has become an urgently important matter for transit agencies. This study aimed to explore the relationship b...
The GTAModel travel demand model, developed at the University of Toronto, currently uses an aggregate transit assignment method that is inconsistent with the agent-based microsimulation structure of the rest of the model system, thereby limiting the effectiveness of the model results. This project seeks to address this gap in capability by integrat...
While premium transit modes such as commuter rail can improve access to opportunities, the higher fares that accompany these services create barriers to their use. Fare-sensitive access measures require accurate estimation of fare costs between origins and destinations. They are not often included in public transit access analyses because of data l...
In transfer-based transit networks, it is critical to synchronise timetables of intersecting routes to reduce passenger transfer times. To this end, this study compares different transfer time optimisation approaches and investigates their solutions comprehensively at the network level as well as for each transfer node individually. Additionally, i...
Passenger railways face reliability challenges resulting from shared track with other trains, limited infrastructure capacity, and rolling stock and trackway that is subject to major failures during service. Dispatchers may have limited contextual information when responding to an emerging delay, and often rely on their own experience to manage an...
Surface transit lines in North America commonly feature a basic service pattern consisting of a single branch of all-stop service, with stops usually tightly spaced. Such a configuration is inefficient for the operator and unattractive for the users, particularly if the prevailing passenger demand is unevenly distributed along the line. In such cas...
As the level of passenger demand in rail transit systems increases, major railway stations in urban centres face serious capacity issues. Both analytical and simulation methods have been used to analyse complex station areas; however, prior efforts have only focused on either train or pedestrian movements with over-simplified assumptions that do no...
Information shared on social media by transit system customers is often candid, localized, and includes in the moment information about emerging events or issues. Twitter provides an unfiltered and timestamped feed of information that can be aggregated to generate valuable insights. Our research aims to identify passenger-related transit incidents...
While premium transit modes such as commuter rail can improve access to opportunities, the higher fares that accompany these services create barriers to their use. Fare-sensitive access measures require accurate estimation of fare costs between origins and destinations. They are not often included in public transit access analyses because of data l...
Unexpected transit service disruptions degrade the quality of service provided to the public. Bus bridging is considered a key response strategy used to handle metro service interruptions, where buses are retracted from scheduled services and deployed to offer shuttle services along disrupted segments. Most transit agencies rely on ad-hoc approache...
The TransitCenter Equity Dashboard tracks how well public transit systems in seven densely populated urban regions in the United States serve their riders and how changes to transit service affect riders over space, time, and cost constraints. The dashboard presents a series of charts and interactive maps that can be used to evaluate variations in...
The outbreak of COVID-19 in 2020 has had drastic impacts on urban economies and activities, with transit systems around the world witnessing an unprecedented decline in ridership. This paper attempts to estimate the effect of COVID-19 on the daily ridership of urban rail transit (URT) using the Synthetic Control Method (SCM). Six variables are sele...
In rapidly-growing metropolitan regions, it is crucial that transportation-related policies and infrastructure are designed to ensure that everyone can participate equitably in economic, social, and civil opportunities. Ridehailing services are touted to improve mobility options, but there is scant research that incorporates this mode within an acc...
This paper presents a large-scale integrated modelling framework that can capture the relationships between travel mode choice, departure time choice and route choices simultaneously. Conventional transportation models have typically been applied to small scale networks to avoid the complexity of the large-scale simulation. While there are differen...
The objective of this research was to map out the greenhouse gas (GHG) footprint of Ontario transit agencies. A system-by-system GHG emissions model was developed to determine which transit agencies are low, medium, or high emitters based on the metric tonnes of carbon dioxide equivalent (CO2e) emitted from mobile sources. A score card was created...
Information shared on social media by transit system customers is often candid, localized, and includes in-the-moment information about emerging events or issues. Twitter provides an unfiltered and timestamped feed of information that can be aggregated to generate valuable insights. Our research aims to identify passenger-related transit incidents...
Unplanned rail disruptions result in substantial delays to passengers and severe effects on the economy of a large city like Toronto. While bus bridging has been a widely adopted method to replace the subway service in such events, its effect on the operational resilience of the subway service is less often studied. This study assesses the resilien...
The rollout of autonomous vehicles (AV) presents an invaluable opportunity to assess the user perception and experience of a new technology that is expected to disrupt the urban mobility system worldwide. To incorporate AV technologies into existing public transit systems, transit agencies need rigorous assessment and validation of AVs in real-worl...
As the level of passenger demand in rail transit systems increases, major railway stations in urban centres face serious capacity issues. Both analytical and simulation methods have been used to analyze complex station areas; however, prior efforts have only focused on either train or pedestrian movements with oversimplified assumptions that do not...
This paper develops an operational strategy in which urban rail transit is used for freight transport. An environment-friendly urban freight transportation alternative is analyzed by employing optimization techniques to support the collaborative transportation of passengers and freight. Practical cases are investigated to test the technical feasibi...
Bunching occurs when transit vehicles are unable to maintain their scheduled headways, resulting in two or more vehicles arriving at a stop in close succession and following each other too closely thereafter. Very few studies have explored the prediction of bunching in real-time, particularly for streetcar services. Predicting the time to bunching...
During subway disruptions, commuters are often left stranded while they wait for bus bridging services. Some are able to change their mode of transport midway through their trip, often by requesting a ride-hailing service like Uber or Lyft if they are affordable. Many agencies use in-service buses to provide bus bridging services during subway disr...
Transit agencies in multiple countries have started piloting the integration of new mobility technologies (NMTs) into their transit services. This article reviews the emerging evidence from NMT-based transit pilots to identify the social equity impacts of NMT–transit integration. We focus on ride-hailing, on-demand transit, microtransit, and active...
Bus routes provide critical lifelines to disadvantaged travelers in major cities. Bus route performance is also more variable than the performance of other, grade-separated transit modes. Yet the social equity of bus operational performance is largely unexamined outside of limited statutory applications. Equity assessment methods for transit operat...
Transit signal priority (TSP) is a traffic control strategy that gives priority to transit vehicles by adjusting intersection signals in real time. The technology is implemented in many major cities and has proved to benefit transit routes in reducing the overall passenger travel time. Unfortunately, there are several problems with TSP that are com...
Demand-responsive transit is a growing phenomenon in Canada, and is being increasingly considered as an alternative to fixed-route transit in lower density suburban and rural areas. This desire to provide coverage service at a lower cost is further driven by the introduction of application-based systems and cloud computing, which can provide more d...
Recently, there have been growing concerns about the negative impacts of rising automobile use and road congestion on personal mobility, safety, air quality and climate change. To address these issues, special attention has been given to improving and expanding transit services in order to attract new riders and retain existing ones. Despite these...
The effects of transit ridership determinants can be quantified as demand elasticities which are often used to inform transit planning and policy making. This study seeks to determine the impacts of transit service supply, fare, and gas prices on ridership by quantifying the short-run and long-run demand elasticities, as well as test whether transi...
Urban rail systems frequently suffer from unexpected service disruptions, which can result in severe delays and user dissatisfaction. “Bus bridging” is the strategy most commonly applied in responding to rail service interruptions in North America and Europe. Buses are pulled from regular routes and dispatched to serve as shuttles along the disrupt...
The time required to transfer between different transit lines is a critical component of passenger travel time. Although transit agencies attempt to design well-coordinated timetables among intersecting lines at the scheduling stage, an operational control method is necessary to maintain the coordinated transfers that may occasionally be disrupted...
With the continuous growth of urban areas around the world, overcrowding in large transit networks has become a persistent problem, with far-reaching impacts similar to those caused by congestion in large road networks. Moreover, instead of serving as a relief for large transportation systems, congested transit networks have increased delay-related...
Many North American cities are increasingly interested in implementing small-scale localized spot treatments to surface routes as a simpler approach than top-down, disruptive route change, or redesign. This research seeks to support the identification of effective spot treatments at intersections using a systematic, data-driven approach. By analyzi...
Although the traffic and transit assignment processes are intertwined, the interactions between them are usually ignored in practice especially for large-scale networks. In this paper, we build a simulation-based traffic and transit assignment model that preserves the interactions between the two assignment processes for the large-scale network of...
The reliability and applicability of traffic operation analyses depends on their ability to integrate relevant input from disparate databases in a seamless and automated manner. Inputs include information on road geometry, traffic composition, and spatial referencing. These databases are collected by different agencies for different purposes. As a...
Bunching is a well-known operational problem for transit agencies and it has negative impacts on service quality and users’ perception. While there has been a substantial amount of literature about understanding the factors associated with bus bunching and strategies used to mitigate the effects of this problem, there has been little research on st...
Modeling the opinion dynamics of transit system riders is key to understanding their needs, motivations and sensitivities for service changes. This can make planning and operations processes to match user profile, hence promoting more transit usage with positive results on sustainable development. This research work investigated the triangulation o...
One of the main challenges facing transit agencies is offering reliable service with minimum number of interruptions and ensuing delays. Although this issue has recently emerged as a top priority in many cities to ensure sustainable social and environmental progress, there has been little research effort to investigate issues surrounding service di...
With the emergence of new technologies, new data sources, and software, it is important to understand the current approaches used by transit agencies in ridership prediction. This study reports the results of a recent web-based survey conducted in 2018 among 36 Canadian transit agencies to understand their current state of ridership prediction prac...
Bus bridging is a key strategy used by transit agencies to handle rail service interruptions. In practice, buses are dispatched from scheduled services to act as temporary shuttles along the disrupted rail segment. This study provides a robust analysis of four factors affecting bus bridging policies: 1) initial dispatch direction of shuttle buses,...
The reliability of public transit networks is of critical importance the world over. As many transit systems are increasingly exposed to various causes of service disruptions, there exists a need to quantitatively measure the operational resilience of a transit network. This paper presents an approach for transit resilience measurement that combine...
Peak period crowding in transit networks mirrors peak hour congestion in road networks, particularly in large cities such as Toronto. One of the effective strategies to tackle this problem is time-based transit fares. One potential unintended consequence of implementing such a strategy, however, can be modal shifts from transit to other modes. In o...
1This study is focused on investigating the commuter behaviour in areas adjacent to commuter rail 2 service, using GO Transit in the Greater Toronto and Hamilton Area (GTHA) as a case study. 3 More specifically, this study aims at developing a better understanding of the mode split of the 4 commuting trips originating in GO rail station catchment a...
Bus bridging a key strategy used by transit agencies to handle rail service interruptions. In practice, buses are dispatched from scheduled services to act as temporary shuttles along the disrupted rail segment. This study provides a robust analysis concerning four factors affecting bus bridging policies: 1) initial dispatch direction of shuttle bu...
For a particular section of a road network, there are multiple sources of quantitative and qualitative traffic information. Quantitative sensors are usually hardware-based, including loop detectors and GPS devices that produce numerical data. Qualitative sensors are usually processed data, including the traffic department’s websites and radio broad...
Transit agencies that operate streetcars use vehicles of varied sizes and characteristics to accommodate demand and service requirements. While some studies have been conducted on the influence of different bus types on service operations, there is limited research on streetcar types. Therefore, this paper examines the impacts of three different ty...
Cities around the world are keen to offer modern urban transit systems that connect various locations in an efficient and reliable manner with the highest degrees of riders’ experience. These systems may consist of various modes such as buses, streetcars (or trams), and rapid transit systems (e.g., subways). In both research and practice, the quali...
Unexpected transit service disruptions degrade the quality of service provided to the public. “Bus bridging” is considered a key response strategy used to handle rail service interruptions, where buses are retracted from scheduled services and deployed to offer shuttle services along disrupted segments. Most transit agencies rely on ad-hoc approach...
High-quality transit service is a vital aspect of any modern city. When unexpected interruptions to the transit service occur, they reduce the quality of service provided to the public. One of the main strategies that is employed to deal with rail service interruptions is “bus bridging,” whereby buses from scheduled services are deployed to offer s...
Transit user behavioural response under disrupted service conditions, specifically how transit riders choose among available mode options to complete their trips, is not well understood. This study aimed to investigate transit user mode choice in response to rapid transit service disruption in the City of Toronto, incorporating such factors as the...