Researchers investigated the testing and evaluation of radio and communication protocol standards for the 5.9 GHz spectrum that has been approved by the Federal Communications Commission for exclusive transportation use. This spectrum allocation is intended for use as Dedicated Short Range Communications (DSRC) in the context of high-value Intelligent Transportation Systems (ITS) applications. In this report, we summarize the Wireless Access in a Vehicular Environment (WAVE) standardization effort for 5.9 GHz DSRC, its current status, and related issues of the IEEE 802.11p and IEEE 1609...
Miguel Street is a winding, narrow route through the Glen Park neighborhood of San Francisco. Until a few years ago, only those living along the road traveled it, and they understood its challenges well. Now it's packed with cars that use it as a shortcut from congested Mission Street to heavily traveled Market Street. Residents must struggle to get to their homes, and accidents are a daily occurrence. The problem began when smartphone apps like Waze, Apple Maps, and Google Maps came into widespread use, offering drivers real-time routing around traffic tie-ups. An estimated 1 billion...
The transportation landscape is in transition. Rising congestion, failing infrastructure, changing behaviors, adapting to a more inclusive definition of mobility, the desire for cleaner and more efficient engines, and grappling with the role of autonomous vehicles and drones, to name just some of the factors, demands that we take a fresh approach to designing for mobility. Yet the rapid pace of technology development is creating emerging trends that are driving change faster than our ability to model, design, and manage them. This could potentially result in undesirable economic,...
The rapid introduction of mobile navigation aides that use real-time road network information to suggest alternate routes to drivers is making it more difficult for researchers and government transportation agencies to understand and predict the dynamics of congested transportation systems. Computer simulation is a key capability for these organizations to analyze hypothetical scenarios; however, the complexity of transportation systems makes it challenging for them to simulate very large geographical regions, such as multi-city metropolitan areas. In this article, we describe enhancements...
The present work proposes a framework to calibrate MFD models using mobile phone data. The three major components to calibrate in the present context include MFD shape, regional trip lengths and path flow distribution. Time dependent penetration rates are estimated by fusing the OD matrix and the Loop Detector Data (LDD). The estimated MFDs are stable with very low scatter. In the following step, macro-paths and their corresponding trip lengths are estimated. Dynamic evolution of trip lengths is demonstrated using the present data, which is otherwise very difficult to capture with other...
This collection provides a contemporary excerpt of “Cities as complex systems”. The contributions have been submitted between April and October 2020. We briefly discuss example papers addressing the themes “urban scaling”, “urban mobility”, “flows in cities”, “spatial analysis”, “information technology and cities”, and “cities in time”. After motivating the intersection of cities and complexity, we provide an introduction and additional thoughts on urban scaling.
In recent years, “smart city” technologies have emerged that allow cities, counties, and other agencies to manage their infrastructure assets more effectively, make their services more accessible to the public, and allow citizens to interface with new web- and mobile-based operators of alternative service providers. This project reviews the academic literature and other sources on potential strengths, weaknesses, and risks associated with smart city technologies. No dataset was found that measures the adoption of such technologies by government agencies. To address this gap, a methodology...
Smart city technologies present opportunities for local governments, while also exposing them to new risks. While privacy threats and algorithmic biases have received significant attention within urban studies, cybersecurity has received far less. Our study examines systematic variation across smart city technologies in cyber-risks. We administered a survey to cybersecurity experts in which they ranked the vulnerabilities, threats, and consequences of potential cyberattacks for nine different smart city technologies. Analysis using a Markov-based approach indicates that cyber-risks vary...
