Zijia Zhong

Zijia Zhong, Mark M. Nejad, Earl E. Lee

Signalized intersections are major sources of traffic delay and collision within the modern transportation system. Conventional signal optimization has revealed its limitation in improving the mobility and safety of an intersection. Unconventional arterial intersection designs (UAIDs) are able to improve the performance of an intersection by reducing phases of a signal cycle. Furthermore, they can fundamentally alter the number and the nature of the conflicting points. However, the driver's confusion, as a result of the unconventional geometric designs, remains one of the major barriers for the widespread adoption of UAIDs. Connected and Automated Vehicle (CAV) technology has the potential to overcome this barrier by eliminating the driver's confusion of a UAID. Therefore, UAIDs can play a significant role in transportation networks in the near future. In this paper, we surveyed UAID studies and implementations. In addition, we present an overview of intersection control schemes with the emergence of CAV and highlight the opportunity rises for UAID with the CAV technology. It is believed that the benefits gained from deploying UAIDs in conjunction with CAV are significant during the initial rollout of CAV under low market penetration.

Zijia Zhong, Joyoung Lee

Accessible pedestrian signal (APS) was proposed as a mean to achieve the same level of service that is set forth by the American with Disability Act (ADA) for the visually impaired. One of the major issues of existing APSs is the failure to deliver adequate crossing information for the visually impaired. This paper presents a mobile-based APS application, namely Virtual Guide Dog (VGD). Integrating intersection information and onboard sensors (e.g., GPS, compass, accelerometer, and gyroscope sensor) of modern smartphones, the VGD application can notify the visually impaired: 1) the close proximity of an intersection and 2) the street information for crossing. By employing a screen tapping interface, VGD can remotely place a pedestrian crossing call to the controller, without the need of using a push button. In addition, VGD informs VIs the start of a crossing phase by using text-to-speech technology. The proof-of-concept test shows that VGD keeps the users informed about the remaining distance as their approaching the intersection. It was also found that the GPS-only mode is accompanied by greater distance deviation compared to the mode jointly operating with both GPS and cellular positioning.

Zijia Zhong, Joyoung Lee

Wireless communication plays a vital role in the promising performance of connected and automated vehicle (CAV) technology. This paper proposes a Vissim-based microscopic traffic simulation framework with an analytical dedicated short-range communication (DSRC) module for packet reception. Being derived from ns-2, a packet-level network simulator, the DSRC probability module takes into account the imperfect wireless communication that occurs in real-world deployment. Four managed lane deployment strategies are evaluated using the proposed framework. While the average packet reception rate is above 93\% among all tested scenarios, the results reveal that the reliability of the vehicle-to-vehicle (V2V) communication can be influenced by the deployment strategies. Additionally, the proposed framework exhibits desirable scalability for traffic simulation and it is able to evaluate transportation-network-level deployment strategies in the near future for CAV technologies.