ITS Berkeley

Achieving Higher Taxi Outflows from a Drop-off Lane: A Simulation-based Study

Yang, Fangyi
Gu. Weihua
Cassidy, Michael J.
Li, Xin
Li, Tiezhu
2020

Lanes used by taxis and other shared-ride vehicles at airports and rail terminals are often congested. The present paper examines congestion-mitigating strategies for a special type of lane inside of which taxis are prohibited from overtaking each other while dropping-off patrons. Taxis must therefore often wait in first-in-first-out (FIFO) queues that form in the lane during busy periods. Patrons may be discharged from taxis upon reaching a desired area near the terminal entrance. When wait times grow long, however, some taxis discharge their patrons in advance of that desired area. The...

Zero-Shot Autonomous Vehicle Policy Transfer: From Simulation to Real-World via Adversarial Learning

Chalaki, Behdad
Beaver, Logan E.
Remer, Ben
Jang, Kathy
Vinitsky, Eugene
Bayen, Alexandre
Malikopoulos, Andreas A.
2020

In this article, we demonstrate a zero-shot transfer of an autonomous driving policy from simulation to University of Delaware's scaled smart city with adversarial multi-agent reinforcement learning, in which an adversary attempts to decrease the net reward by perturbing both the inputs and outputs of the autonomous vehicles during training. We train the autonomous vehicles to coordinate with each other while crossing a roundabout in the presence of an adversary in simulation. The adversarial policy successfully reproduces the simulated behavior and incidentally outperforms, in terms of...

Introduction: Control Problems for Conservation Laws with Traffic Applications

Bayen, Alexandre
Monache, Maria Laura Delle
Garavello, Mauro
Goatin, Paola
Piccoli, Benedetto
Bayen, Alexandre
2022

This book focuses on control problems for conservation laws, i.e., equations of the type: ∂tu+∂xf(u)=0ut+(f(u))x=0,$$\displaystyle \partial _t\, u + \partial _x\, f(u) = 0 \qquad u_t+(f(u))_x=0, $$where u:ℝ+×ℝ→ℝn$$u:\mathbb {R}^+\times \mathbb {R} \to \mathbb {R}^n$$is the vector of conserved quantities and f:ℝn→ℝn$$f:\mathbb {R}^n\to \mathbb {R}^n$$is the flux. Most results will be given for the scalar case (n = 1), but we will present few results valid in the general case.

Emergent Complexity and Zero-Shot Transfer via Unsupervised Environment Design

Dennis, Michael
Jaques, Natasha
Vinitsky, Eugene
Bayen, Alexandre
Russell, Stuart
Critch, Andrew
Levine, Sergey
2020

A wide range of reinforcement learning (RL) problems --- including robustness, transfer learning, unsupervised RL, and emergent complexity --- require specifying a distribution of tasks or environments in which a policy will be trained. However, creating a useful distribution of environments is error prone, and takes a significant amount of developer time and effort. We propose Unsupervised Environment Design (UED) as an alternative paradigm, where developers provide environments with unknown parameters, and these parameters are used to automatically produce a distribution over valid,...

Easy-to-Compute Index for Identifying Built Environments that Support Walking

Schneider, RJ
Rodriguez, DA
Young, HM
2006

The variety and spatial co-variation of built environment attributes associated with non-automobile travel have resulted in the estimation of composite scores or indices summarizing these attributes. This paper builds on prior practical and research applications of these environmental scores or indices by proposing and testing a built environment index (BEI) calculated at the traffic analysis zone and that relies predominantly on widely available data. By computing the BEI using three different analytical methods used in prior research (principal components analysis, cluster analysis...

Creative Reallocation of Curbs, Streets, Sidewalks Accelerated by the Pandemic May Be Here to Stay

Shaheen, Susan, PhD
Cohen, Adam
Broader, Jacquelyn
2023

Curb space has been traditionally designed for private vehicle parking, public transit, and passenger and commercial loading. However, in recent years, a growing number of newservices and activities have increased the demand for limited curb space, including passenger pick-up and drop-off; last-mile delivery (e.g., courier network services, personal delivery devices); electric vehicle (EV) charging; micromobility parking and use (e.g., personally owned and shared bikes and scooters); and carsharing services. The curb serves a variety of functions such as vehicle and device storage (...

COVID-19 Has Significantly Impacted the Mobility and Activities of the Senior Population in Contra Costa County

Ragland, David R.
Schorr, Glenn
Felschundneff, Grace
2020

Meeting the mobility needs of an aging population is one of the most substantial challenges facing California in the coming decades. The number of residents age 60 and above will grow to 13.9 million by 2050, representing over 25% of the state population. Meanwhile, the number of residents age 85 and above is expected to increase by over 70% between 2010 and 2030. In 2018, the Safe Transportation Research and Education Center (SafeTREC) at UC Berkeley conducted a survey on transportation mobility issues among older adults in Contra Costa County in California. Results indicated, among other...

Comparing Methods and Data Sources for Classifying Bicycle Level of Traffic Stress: How Well Do Their Outcomes Agree?

Harvey, C
Rodriguez, DA
Fang, K
2024

Level of Traffic Stress (LTS) metrics are widely used to examine how bicyclists may perceive stress along urban streets and identify opportunities for infrastructure improvements. The intuitiveness of the original method, which condensed 18 input variables into four levels, has made LTS very popular among practitioners. Nonetheless, it can be challenging to collect all required inputs. In response, numerous alternative methods have been developed with fewer or different inputs drawn from more general sources, such as OpenStreetMap (OSM) or GIS datasets from local agencies. These...

Authorized Vehicles Only: Police, Parking, and Pedestrian Access in New York City

Moran, Marcel E
2023

Sidewalks and crosswalks serve little purpose for pedestrians if they are routinely obstructed by automobiles. In New York City, local journalists and transportation advocates have drawn attention to this occurring, particularly in certain settings. Specifically, there is consistent photographic evidence that streets surrounding New York Police Department (hereafter, NYPD) offices are replete with cars parked on the sidewalk and within crosswalks. Though clearly problematic for pedestrians and abutting residents and local businesses, this type of parking behavior has not been studied...

Are Shelters in Place? Mapping the Distribution of Transit Amenities via a Bus-Stop Census of San Francisco

Moran, Marcel E
2022

Transit stops serve as crucial components of journeys for riders, but their condition is often left out of equity considerations. Two important empirical questions are what stop amenities, such as places to sit, clear sign age, shelters for inclement weather, and unobstructed curbs are present, and how are they distributed across systems, which may reveal neighborhood or route-specific disparities. San Francisco, CA represents an ideal case for which to pursue this question, given it maintains a ‘transit first’ policy directive that mandates public space prioritize transit over private...