Travel Behavior

The Path Inference Filter: Model-Based Low-Latency Map Matching of Probe Vehicle Data

Hunter, Timothy
Abbeel, Pieter
Bayen, Alexandre M.
2014

We consider the problem of reconstructing vehicle trajectories from sparse sequences of GPS points, for which the sampling interval is between 1 s and 2 min. We introduce a new class of algorithms, which are altogether called the path inference filter (PIF), that maps GPS data in real time, for a variety of tradeoffs and scenarios and with a high throughput. Numerous prior approaches in map matching can be shown to be special cases of the PIF presented in this paper. We present an efficient procedure for automatically training the filter on new data, with or without ground-truth...

To Pool or Not to Pool? Understanding the Time and Price Tradeoffs of OnDemand Ride Users – Opportunities, Challenges, and Social Equity Considerations for Policies to Promote Shared-Ride Services

Shaheen, Susan
Lazarus, Jessica
Caicedo, Juan
Bayen, Alexandre
2021

On-demand mobility services including transportation network companies (also known as ridesourcing and ridehailing) like Lyft and Uber are changing the way that people travel by providing dynamic mobility that can supplement public transit and personal-vehicle use. However, TNC services have been found to contribute to increasing vehicle mileage, traffic congestion, and greenhouse gas emissions. Pooling rides ⎯ sharing a vehicle by multiple passengers to complete journeys of similar origin and destination ⎯ can increase the average vehicle occupancy of TNC trips and thus mitigate some of...

Learning Generalizable Multi-Lane Mixed-Autonomy Behaviors in Single Lane Representations of Traffic

Kreidieh, Abdul Rahman
Zhao, Yibo
Parajuli, Samyak
Bayen, Alexandre
2021

Reinforcement learning techniques can provide substantial insights into the desired behaviors of future autonomous driving systems. By optimizing for societal metrics of traffic such as increased throughput and reduced energy consumption, such methods can derive maneuvers that, if adopted by even a small portion of vehicles, may significantly improve the state of traffic for all vehicles involved. These methods, however, are hindered in practice by the difficulty of designing efficient and accurate models of traffic, as well as the challenges associated with optimizing for the behaviors of...

Conclusion: Reflections and Lessons from the Pandemic

Bayen, Alexandre M.
Jayakrishnan, R.
Circella, Giovanni
Loukaitou-Sideris, Anastasia
2023

This concluding chapter presents a summary of the research findings in the previous chapters, along with some reflections for each of the five themes of the book and a discussion of necessary future responses (post-pandemic or in the event of a new pandemic) and topics that require further exploration. The pandemic brought into sharp relief pre-existing social disparities and affected vulnerable populations the most. The economic impacts of the pandemic were diverse and varied by geography, but again certain geographies and economic sectors were more buffered from negative outcomes than...

Driver Memory: Motorist Selection and Retention of Individualized Headways in Highway Traffic

Cassidy, Michael J.
Windover, John R.
1998

The paper presents evidence that (1) drivers have different personalities in that they follow vehicles at different headways, and (2) drivers retain their personalities in that each driver tends to maintain his headway over space and, in some instances, drivers return to their headways after being forced by a traffic disturbance to alter them temporarily. This attribute, which we term driver memory, is revealed by visual inspection of modified curves of measured cumulative vehicle arrival number versus time.

Identification and Integration of Commercial Heavy Vehicle Retarders

Druzhinina, Maria
Moklegaard, Lasse
Stefanopoulou, Anna G.
2002

This report describes the development and experimental validation of a coordination scheme between friction and discretely variable compression brakes for a Class 8 Freightliner truck used as a development platform in the California PATH program. The coordination scheme that we developed maintains the speed tracking performance of the nominal PID controller which was originally designed by the UCLA team for the case of friction brakes only.....

Traffic Management System Performance Using Regression Analysis

Levinson, David
Chen, Wei
2006

This study can be viewed as a preliminary exploration of using regression analysis to evaluate long-run traffic management system performance. Four main traffic management systemsin the Twin Cities metro area --- Ramp Metering System, Variable Message Signs (VMS), Highway Helper Program, and High Occupancy Vehicle (HOV) System were evaluated based on multiple regression models. Link speed and incident rate were employed as the response variable separately. Consequently, regression analysis can be a simple and effective research method for testing the macroscopic association between traffic...

Testing Daganzo's Behavioral Theory for Multi-lane Freeway Traffic

Chung, Koohong
Cassidy, Michael
2002

This report describes the detailed, albeit still preliminary study of traffic on stretches of two different freeways. Both were plagued by merge bottlenecks. The first of these sites is the Gardiner Expressway, a 3.3 km long freeway stretch in Toronto, Canada. The site was selected because of its suitable geometry (i.e. its merge bottleneck) and its well-tuned loop detectors located upstream and downstream of the bottleneck. The site thus provided for an exceptionally good “laboratory” for testing Daganzo’s behavior theory of drivers (Daganzo, 1999). It turns out that the observations from...

Collisions in Freeway Traffic: Influence of Downstream Queues and Interim Means to Address Them

Li, Zhibin
Chung, Koohong
Cassidy, Michael J.
2013

Findings from previous studies indicate that a freeway traffic collision is more likely to occur in close physical proximity to the tail of a queue. The implication is that collision likelihood increases when drivers abruptly alter their trajectories (e.g., by decelerating or changing lanes) on encountering the queue. The implication is supported and bolstered with new and detailed data that were painstakingly extracted from two freeway stretches in California. These data show how the likelihood of collision increases as both the spatial and the temporal proximities to the tail of an...

Assessing the Role of AVL in Demand Responsive Transportation Systems

Gillen, David
Raffaillac, Julie
2002

Many-to-many demand responsive transportation systems consist of vehicles which take passengers from their origins to their destinations within a service area. In dial-a-vehicle systems, in order to circumvent the undesirable feature of taxicab systems, vehicles are allowed to deviate from their direct route to serve other passengers and the emphasis is on building efficient tours to increase vehicle productivity. This strategy increases riding times but also increases average occupancy and productivity of the vehicles, and hence decreases average waiting times. A similar problem is faced...