Hani S. Mahmassani

Hani S. Mahmassani
Northwestern University | NU · Northwestern University Transportation Center (NUTC)

PhD MIT

About

523
Publications
151,445
Reads
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17,846
Citations
Introduction
Hani S. Mahmassani is Director of the Northwestern University Transportation Center (NUTC), Northwestern University. Hani does research in Network Modeling and Algorithms, Traffic Science and Operations Research, Travel Behavior and Econometrics, and Freight and Logistics Systems. Current projects include analysis, modeling and simulation methodologies for connected and autonomous vehicle systems, multimodal network models, and predictive analytics for real-time transportation and logistics systems.
Additional affiliations
August 2007 - present
Northwestern University
Position
  • Professor (W.A. Patterson Chair in Transportation) and Director
Education
August 1978 - December 1981
Massachusetts Institute of Technology
Field of study
  • Transportation Systems
January 1976 - July 1978
Purdue University
Field of study
  • Transportation Engineering

Publications

Publications (523)
Article
This paper presents and tests modified service network design formulations that account for five levels of truck automation in a daily load planning setting. Given daily updates of load information , the paths for the five deployment scenarios are adjusted using two daily updating strategies. Both strategies start with a base plan in which paths ar...
Article
The flexible nature of on-demand ride services provided by transportation network companies (TNC) has resulted in unique supply-side challenges as the industry deals with the COVID-19 pandemic. Early during the pandemic, there was a 70% decrease in the number of drivers accepting trips on TNC platforms, as individual drivers chose to reduce their r...
Article
This paper studies the tax intervention applied to transportation network company (TNC) trips starting on January 6, 2020 in the City of Chicago. An interrupted time series (ITS) with an autoregressive integrated moving average (ARIMA) methodology is employed to infer the causal impact of the intervention on the percentage of shared trips and the c...
Article
To ease urban congestion, advanced air mobility (AAM) proposes the use of small aerial vehicles at low altitudes for uses such as package delivery and passenger services. In a developed state, an AAM service is predicted to involve thousands of trips daily, creating much higher densities of aircraft than currently exist in any airspace. Airspace st...
Article
Urban air taxi (UAT) is envisioned as a point-to-point, (nearly) on-demand, and per-seat operation of passenger-carrying urban air mobility (UAM) in its mature state. A high flight load factor has been identified as one of the influential components in the successful operation of UAT. However, the uncertainties in demand, aircraft technology, and c...
Article
This paper investigates the potential of autonomous minibuses which take on-demand directional routes for pick-up and drop-off in a grid network of wider area with low density, followed by fixed routes in areas with greater demand. Mathematical formulation for generalized costs demonstrates its benefits, with indicators proposed to select existing...
Article
This paper studies a mixed-service operation of shared-use autonomous mobility systems (SAMS) where customers can request rides either immediately or through reservations and use the vehicle for a point-to-point service or a time-slot-based rental service, respectively. Three autonomous-vehicle-to-user assignment strategies are presented: a first-c...
Article
This study uses GPS data of 1461 participants at a planned special event organized in Oshkosh, Wisconsin named AirVenture to characterize their spatio-temporal activity participation behavior. The GPS data is used to derive activity sequences for participants and study the attractiveness of various activities at the event site. A validation procedu...
Article
The node-place model has been used in previous studies to categorize urban transit rail stations, and to study impacts on transit station ridership. Similar studies have not been performed for intercity rail station ridership. This study uses the node-place model to examine the station-level factors affecting station ridership on the Amtrak network...
Article
The rapid onset of the COVID-19 pandemic in March 2020 marked a challenging time for the US and its freight industry. Manufacturing slowed, consumer purchasing patterns changed, and for many, shopping moved online. The freight industry suffered a sharp decline in shipments, followed by a surprisingly quick rebound. The industry had to adapt quickly...
Article
The COVID-19 pandemic required employees and businesses across the world to rapidly transition to work from home over extended periods, reaching what is likely the upper bound of telework in many sectors. Past studies have identified both advantages and disadvantages of teleworking. The pandemic experience offers a unique opportunity to examine emp...
Article
This paper focuses on the problem of finding optimal trajectory-adaptive routing strategies in stochastic time-varying networks with generalized spatio-temporal correlations. A representation for jointly distributed continuous link travel times across the entire network with time-varying distributions and correlation structures is presented, and th...
Presentation
Full-text available
Digital technologies are making considerable computing power and intelligence available to individuals through ubiquitous connected mobile devices. While the first and second waves of ITS deployment have focused on infrastructure-based approaches to transportation system management, the coming wave leverages individual-level sensing, multimodal mob...
Article
As congestion levels increase in cities, it is important to analyze people’s choices of different services provided by transportation network companies (TNCs). Using machine learning techniques in conjunction with large TNC data, this paper focuses on uncovering complex relationships underlying ridesplitting market share. A real-world dataset provi...
Presentation
Full-text available
Transportation is undergoing deep and significant transformation, seeking to fulfill the promise of connected urban mobility for people and goods, while limiting its carbon footprint. Achieving the promise of these technologies calls for concomitant development of the underlying intelligence through advanced distributed software tools that implemen...
Article
Large-scale planned special events (PSEs) can pose unique transportation and logistics challenges. Data collection and simulation are important tools to address these challenges, although they are often difficult because of event size and complexity. This paper discusses methods to address the challenge of multimodal simulation at large PSEs throug...
Article
Network macroscopic fundamental diagrams (NMFD) and related network-level traffic dynamics models have received both theoretical support and empirical validation with the emergence of new data collection technologies. However, the extent to which network-level macroscopic traffic models may be ready for practical implementation remains to be ascert...
Presentation
Full-text available
The conduct of economic and social activities through information and communication technologies enabled the world to continue functioning under an unprecedented pandemic-induced disruption in normal activity and physical mobility patterns. Virtual engagement enabled work, school, entertainment, medicine and commerce to continue for extended period...
Article
Urban air mobility (UAM) is an emerging mode that promises to provide relief to congested urban streets. UAM relies on airspace, however, which is an exhaustible resource considering minimum aircraft separation requirements. In light of these requirements and UAM vehicle attributes, a simulation is developed to explore UAM traffic flows and congest...
Article
One of the ways to design more effective signal control strategies is to leverage and synthesize connected vehicle generated (CVG) information to identify traffic states for the controller to operate in a predictive, yet vehicle-actuated manner. The contribution of this paper is twofold: (1) it presents a framework for an advanced, online, signal c...
Article
Transportation research has increasingly focused on the modeling of travel time uncertainty in transportation networks. From a user’s perspective, the performance of the network is experienced at the level of a path, and, as such, knowledge of variability of travel times along paths contemplated by the user is necessary. This paper focuses on devel...
Presentation
We take urban mobility to the next level by considering shared mobility services offered through automated electric vertical take-off and landing (eVTOL) vehicles (“flying taxis”), enabled by new generation of eVTOL aircraft. We present various concepts for service operations at urban/regional levels, along with algorithms adapted for the real-time...
Article
Urban air taxi (UAT) operation has gained traction with the advancements in distributed electric propulsion and the emergence of electric vertical take-off and landing aircraft. Start-up companies and aircraft manufacturers are pursuing the possibility of operating UAT at scale in urban and suburban areas and at an affordable price. However, consid...
Book
Full-text available
The rapid onset of the COVID-19 pandemic in March 2020 marked a challenging time for the country and the U.S. freight industry. Manufacturing slowed, consumer purchasing patterns changed, and for many, shopping moved online. The freight industry suffered a sharp decline in shipments, followed by a surprisingly quick rise. The movement of goods by f...
Article
The goal of this paper is to develop a modeling framework that captures the inter-decision dynamics between mobility service providers (MSPs) and travelers that can be used to optimize and analyze policies/regulations related to MSPs. To meet this goal, the paper proposes a tri-level mathematical programming model with a public-sector decision make...
Preprint
Full-text available
The goal of this paper is to develop a modeling framework that captures the inter-decision dynamics between mobility service providers (MSPs) and travelers that can be used to optimize and analyze policies/regulations related to MSPs. To meet this goal, the paper proposes a tri-level mathematical programming model with a public-sector decision make...
Poster
This study presents a novel ensemble learning approach called stacking for real-time short-term traffic state prediction. The approach consists of a level-1 meta-learner that combines predictions from several different level-0 models by making use of the past performance information of the level-0 models. The meta-learner consists of least square e...
Presentation
A focus of road network weather management systems is on integrating emerging communication technologies into transportation agencies’ weather-responsive efforts in order to enhance their effectiveness and efficiency. An important opportunity and challenge is to bring connected vehicle (CV)-enabled technology elements into real-time operational dec...
Article
In an era of emerging vehicle automation technologies and advanced traffic management strategies, traffic simulation has become an indispensable tool for giving agencies the insight they need for adoption and implementation decisions. The importance of calibration to ensure reliability of the simulation results cannot be over-stated. Current practi...
Article
Connected environments offer more information, improved data availability and quality which can lead to better decision making; new meaningful information adds new functionalities and opportunities to advance operational efficiency. Can traffic signal system efficiency and mobility be measured and enhanced in innovative and meaningful ways by combi...
Conference Paper
This paper studies the problem of estimation and computation of reliable least-time paths in stochastic time-varying (STV) networks with spatio-temporal dependencies. For a given desired confidence level α, the least-time paths from any origin to a given destination node are to be found over a desired planning horizon. In STV networks, least-time p...
Presentation
1. Broadest, deepest and longest natural experiment in the use of ICT for tele-activities and e-processes in modern history. From telework to e-learning, telemedicine to e-shopping and near complete reliance on e-commerce and home delivery, activity and mobility patterns have been upended and transformed dramatically. 2. “Never let a good crisis g...
Article
Reliability is a measure of network performance that reflects the ability of the network to provide predictable travel times. Deviations from planned travel times can increase travel costs for users. To improve the system's performance, it is crucial to identify sources of unreliability, particularly the location on the network of unreliable perfor...
Article
Traffic flow breakdown is the abrupt shift from operation at free-flow conditions to congested conditions and is typically the result of complex interactions in traffic dynamics. Because of its stochastic nature, breakdown is commonly predicted only in a probabilistic manner. This paper focuses on using stationary aggregated traffic data to capture...
Presentation
Full-text available
This presentation addresses impact of Covid 19 crisis on supply chains in North America, based on industry interviews and an informal sample of selected carriers and shippers. Supply chain disruptions occurred primarily at nodes rather than along links. The transportation system displayed considerable resilience and continued to deliver throughout....
Conference Paper
Information and Communication Technologies, or ICT,have rapidly emerged asan integral element of everyday life, interactingin an essential manner with mobility and the activity patterns that engender it. The current paper reflects uponthistrendandthe opportunities and challenges itrepresents.Givenmore than three decades of research in the domain of...
Article
Full-text available
Information and Communication Technologies, or ICT,have rapidly emerged asan integral element of everyday life, interactingin an essential manner with mobility and the activity patterns that engender it. The current paper reflects uponthistrendandthe opportunities and challenges itrepresents.Givenmore than three decades of research in the domain of...
Article
Freight forecasting is essential for managing, planning operating and optimizing the use of resources. Multiple market factors contribute to the highly variable nature of freight flows, which calls for adaptive and responsive forecasting models. This paper presents a demand forecasting methodology that supports freight operation planning over short...
Article
This paper presents a quantitative analysis of the operations of shared-ride automated mobility-on-demand services (SRAMODS). The study identifies (i) operational benefits of SRAMODS including improved service quality and/or lower operational costs relative to automated mobility-on-demand services (AMODS) without shared rides; and (ii) challenges a...
Article
Network travel time reliability can be represented by a relationship between network space-mean travel time and the standard deviation of network travel time. The primary objective of this paper is to improve estimation of the network travel time reliability with network partitioning. We partition a heterogeneous large-scale network into homogeneou...
Article
Opinions regarding emergent sustainable transportation alternatives, such as bikeshare and e-scooters, and more traditional green alternatives like public transit, spread through social networks via opinion diffusion mechanisms , like word-of-mouth and mass media. The impact of social media on diffusion of sustainable mobility opinions is not well-...
Presentation
A traffic prediction model that forecasts with a fine resolution over a long horizon can be instrumental in real world advanced traffic management applications. While many existing models have been studied for multi-step traffic prediction, empirical studies reveal there is no single best model that universally outperforms others. In order to inves...
Presentation
Weather information is a critical input in traffic prediction due to its explicit and inherent impact on both demand and supply sides of road traffic. While there are several studies on weather-related traffic dynamic modeling in an operational level, weather-associated demand calibration has received little attention. Analytical papers on the corr...
Article
Full-text available
Fleet operators rely on forecasts of future user requests to reposition empty vehicles and efficiently operate their vehicle fleets. In the context of an on-demand shared-use autonomous vehicle (AV) mobility service (SAMS), this study analyzes the trade-off that arises when selecting a spatio-temporal demand forecast aggregation level to support th...
Article
This study aims to evaluate and quantify the impact of demand forecast spatial resolution on the operational performance of a shared-use automated vehicle (AV) mobility service (SAMS) fleet. To perform the evaluation, this study employs an agent-based modeling framework that includes user requests, AVs, and an SAMS fleet controller. In the simulati...
Presentation
KEY TAKEAWAYS 1. Transportation and mobility industries undergoing major disruptive influences: technology, players, concepts. 2. Forces transforming mobility systems – no longer dependent on public infrastructure investment. Connectivity through C-V2X (Advanced LTE, 5G) rather than DSRC. 3. Emergence and growing role for shared mobility fleets (au...
Article
Providing quality transit service to travelers in low-density areas, particularly travelers without personal vehicles, is a constant challenge for transit agencies. The advent of fully-autonomous vehicles (AVs) and their inclusion in mobility service fleets may allow transit agencies to offer better service and/or reduce their own capital and opera...
Article
This study investigates the prediction and mitigation of the phenomenon of traffic flow breakdown when affected by varying weather conditions. First, the probability of breakdown occurrence is examined using a survival analysis approach to obtain distributions of pre-breakdown flow rates under different weather conditions. Second, pre-breakdown flo...
Article
Origin–destination (O–D) demand is a critical component in both online and offline dynamic traffic assignment (DTA) systems. Recent advances in real-time DTA applications in large networks call for robust and efficient methodologies for online O–D demand estimation and prediction. This study presents a day-to-day learning framework for a priori O–D...
Conference Paper
Simulation frameworks for autonomous mobility-on-demand (AMoD) systems are currently implemented as round-based games, where the real-world simulation time effectively stops until the fleet operator and users finish their decision-making processes. As such, these decisions, which take time to complete in the real-world, are unrealistically treated...
Article
This paper presents a first-order approach integrated with activity-based modeling and dynamic traffic assignment framework to model the impact of autonomous vehicles on household travel and activity schedules. By considering shared rides among household members, mode choices, re-planning of departure times, and the rescheduling of activity sequenc...
Article
This paper examines a new hybrid intercontinental freight transport alternative (IFTA) that combines a logistics island (i.e. an offshore container port), vertical take-off and landing (VTOL) aircraft, and ocean vessel transport. The hybrid IFTA offers a ‘midway’ alternative for intercontinental shippers that is cheaper (and slower) than convention...
Article
In real-time simulation-based dynamic traffic assignment, selection of the most suitable demand from the library of demands calibrated offline improves the accuracy of the prediction. In the era of data explosion, relying on contextual and rule-based pattern matching logic does not seem sufficient. A rolling horizon scheme for real-time pattern mat...
Article
This paper is intended to mine historical data by presenting a scenario clustering approach to identify appropriate scenarios for mesoscopic simulation as a part of the evaluation of transportation projects or operational measures. It provides a systematic and efficient approach to select and prepare effective input scenarios for a given traffic si...
Presentation
Since the 2000’s, researchers have been designing and examining the potential of visualizing high-resolution signal and vehicle trajectory data for the purpose of gaining better insight into traffic control system performance, along with other representative measures of effectiveness. Along with technological advancements, obtaining finer granulari...
Conference Paper
Network travel time reliability can be represented by a relationship between network space-mean travel time and the standard deviation of network travel time. The primary objective of this paper is to improve estimation of the network travel time reliability with network partitioning. We partition a heterogeneous large-scale network into homogeneou...
Article
Full-text available
Providing quality transit service to travelers in low-density areas, particularly travelers without personal vehicles, is a constant challenge for transit agencies. The advent of fully-autonomous vehicles (AVs) and their inclusion in mobility service fleets may allow transit agencies to offer better service and/or reduce their own capital and opera...
Article
Connectivity and automation are expected to enhance safety and efficiency in transportation systems. Connectivity will provide information to drivers/autonomous vehicles to enhance decision-making reliability at the operational and tactical levels. Consequently, drivers are more likely to execute safe and efficient maneuvers and autonomous vehicles...
Article
Taxi fleets serve a significant and important subset of travel demand in major cities around the world. This paper characterizes the Chicago taxi fleet operational network using complex network metrics and analyzes the operational efficiency of individual taxis over the past four years using an extensive taxi-trip dataset. The dataset, recently rel...
Book
Full-text available
This project developed a conceptual framework for an analysis, modeling, and simulation system for evaluating the impacts of connected and automated vehicle (CAV) technologies on transportation facilities at the strategic and operational levels, providing the basis for future development of CAV-enabled evaluation tools. The objective of this projec...
Technical Report
Full-text available
This project developed a conceptual framework for an analysis, modeling, and simulation (AMS) system for evaluating the impacts of connected and automated vehicle (CAV) technologies on transportation facilities at the strategic and operational levels, providing the basis for future development of CAV-enabled evaluation tools. The objective of this...
Article
The ongoing demographic transition from baby boomers to millennials and technology-fueled evolution of transportation bring to the fore key trends that will determine how the future of transportation systems will unfold. This paper examines the implications of such trends on travel behavior by quantifying the impacts of a technologically engaged ch...
Article
This paper presents a modeling framework for the planning of spatially distributed public service facilities. The framework assists in determining the locations and capacities of public facilities in different contexts including urban planning, architectural design, and special events. Given a preliminary set of feasible facility locations, the fra...
Article
This paper presents the main findings of a simulation-based study to evaluate incidents in pedestrian/crowd tunnels and similar elongated confined facilities, with high-volume heterogeneous traffic. These incidents, when occur, imposes hazardous conditions that always result in significant number of fatalities. The aim of this study is to understan...
Article
Traffic congestion is a complex phenomenon triggered by a combination of multiple interacting factors. One of the main factors is the disturbances caused by individual vehicles, which cannot be identified in aggregate traffic data. Advances in vehicle wireless communications present new opportunities to measure traffic perturbations at the individu...
Article
Traffic shockwaves reflect a transition from the free-flow traffic state to the congested state. They create potentially unsafe situations for drivers, increase travel time, and significantly reduce freeway capacity. Several shockwave detection methods based on loop detector data and other traditional databases have been around for years. However,...
Article
Dynamic speed limits (DSLs) are used to improve safety and mobility on freeways in unfavorable traffic conditions due to recurring congestion, roadworks, incidents, or adverse weather. The evaluation of in-field deployment reveals that the effectiveness of DSLs can be hampered by low compliance rates or lack of inherent capacity. With the emergence...
Article
Motivated by the growth of ridesourcing services and the expected advent of fully-autonomous vehicles (AVs), this paper defines, models, and compares assignment strategies for a shared-use AV mobility service (SAMS). Specifically, the paper presents the on-demand SAMS with no shared rides, defined as a fleet of AVs, controlled by a central operator...
Presentation
Full-text available
Presented in a plenary session on Understanding, Modeling, and Steering Mobility Futures. Makes the case of Modeling as a Service (ModaaS)-- to enable agencies to access portfolio of modeling tools for different purposes, and address critical questions related to deployment and impact of new technologies.
Article
This paper separately analyzes the impacts of weather and seasonality on commute mode choice using a stated- preference (SP) survey. The study’s twin objectives include quantifying the relative attractiveness of a flexible transit mode under adverse weather and analyzing the heterogenous impacts of seasonality and weather on different segments of t...
Chapter
Significant progress has been observed in recent years in the development of connected and automated vehicles (CAVs). Such progress has been publicized through the latest products/applications being released or announced by the industry. However, there is a limited knowledge on the impact of CAV technologies on surface transportation network perfor...
Presentation
Full-text available
Like many other domains, transportation is undergoing deep and significant transformation, seeking to fulfill the promise of connected mobility for people and goods, while limiting its carbon footprint. The advent of autonomous vehicles has the potential to change the economics ownership and use of private automobiles, likely accelerating trends to...
Presentation
Full-text available
The travel modeling field has evolved from an exclusive focus on flows, to recognizing that these flows result from travel decisions made by people, and ultimately that travel choices are generally made to satisfy people’s engagement in a set of economic and social activities. Recker was instrumental in the development of the activity-based perspec...
Article
Full-text available
Connectivity and automation are expected to enhance safety and efficiency in transportation systems. Connectivity will provide information to drivers/autonomous vehicles to enhance decision-making reliability at the operational and tactical levels. Consequently, drivers are more likely to execute safe and efficient maneuvers and autonomous vehicles...
Article
This paper illustrates a ride matching method for commuting trips based on clustering trajectories, and a modeling and simulation framework with ride-sharing behaviors to illustrate its potential impact. It proposes data mining solutions to reduce traffic demand and encourage more environment-friendly behaviors. The main contribution is a new data-...
Article
Full-text available
Urban travel demand, consisting of thousands or millions of origin–destination trips, can be viewed as a large-scale weighted directed graph. The paper applies a complex network-motivated approach to understand and characterize urban travel demand patterns through analysis of statistical properties of origin–destination demand networks. We compare...
Article
This paper presents a spatio-temporal trajectory clustering method for vehicle trajectories in transportation networks to identify heterogeneous trip patterns and explore underlying network assignment mechanisms. The proposed algorithm ST-TOPOSCAN is designed to consider both temporal and spatial information in trajectories. We adopt the time-depen...
Presentation
Full-text available
The emergence and adoption of autonomous vehicles is expected to accelerate certain trends already underway in terms of shared urban mobility, and to enable new mobility service models that bridge traditional transit service and personal mobility. Autonomous vehicles will enable new forms of mobility supply. By eliminating the cost and performance...
Article
Location-based social networking data provide an important new dimension in understanding travel choice behaviour, providing high levels of location and time accuracy over long time frames in conjunction with explicit friendship network information. Such data allow examination of location choice dynamics and social networking aspects explicitly. Th...