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    <title>Transport Research International Documentation (TRID)</title>
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    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Impact of Network Latency on the Lateral Control in Automated Vehicle Marshalling</title>
      <link>https://trid.trb.org/View/2724718</link>
      <description><![CDATA[Automated Vehicle Marshalling (AVM) is the first functionally safe Level 4 automated driving system. It consists of the wireless control of unoccupied vehicles at low speed in well-defined environments, such as parking facilities or manufacturing plants. The driverless operation in an AVM system is achieved by transmitting control messages between connected vehicles and intelligent infrastructure. Similar to other wireless applications, network reliability poses a major challenge to ensuring safe automated driving. An AVM system must provide uninterrupted communication between the vehicle and the infrastructure at a stable frequency. However, wireless systems usually suffer from varying latencies and network disturbances. In this context, international organizations and automotive industry contributors have defined requirements specifying network performance, communication interfaces, and message formats for different AVM use cases. These requirements cover communication aspects without involving core automated driving functions, such as vehicle motion control, which are also decisive in ensuring the safety of the overall system. Therefore, studying communication factors in combination with vehicle motion control offers better interpretability of system capabilities. In this work, we investigate the trade-off between communication specifications and vehicle lateral control within an AVM framework implemented on a real vehicle. We aim to address the limitations that may arise under real-world AVM driving conditions. First, we revisit the current technical specifications to highlight the specific AVM messages relevant to vehicle lateral control. Then, we propose a testing framework by establishing communication with the test vehicle over a Wi-Fi network using multiple access points deployed across an indoor parking facility and an outdoor test track. Thus, we obtain a quantitative analysis of network factors, such as latency, in different driving environments. In the next step, we present a Model Predictive Control (MPC) approach that uses the AVM control messages to achieve robust vehicle lateral control. By evaluating the control performance under communication conditions, we assess the impact of network latency on vehicle lateral control. This work provides a baseline for exploring the limitations of AVM and deriving potential optimizations.]]></description>
      <pubDate>Tue, 28 Jul 2026 12:27:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/2724718</guid>
    </item>
    <item>
      <title>A hierarchical Wi-Fi log data processing framework for human mobility analysis in multiple real-world communities</title>
      <link>https://trid.trb.org/View/2491361</link>
      <description><![CDATA[Wi-Fi log data, including communication actions between clients and Access Points (APs), can be used to infer human movement and travel activity and thus would serve as a reliable data source for human mobility analysis. As more and more modern cities or communities provide public free Wi-Fi services, a vast amount of public Wi-Fi log data will be collected and have the potential to be used to characterize human travel patterns and thus develop more effective urban transportation management strategies. However, Wi-Fi log data processing is not trivial. Wi-Fi networks established by various internet equipment manufacturers and devices have different network settings and log file formats. Additionally, the complexity of Wi-Fi log data, along with the ping-pong phenomenon and invalid messages, can result in analysis bias and errors. Though previous studies have processed the specific Wi-Fi log data individually in different ways, a common framework that can address public Wi-Fi data from different locations is needed to improve data processing efficiency and analysis effectiveness. This study proposed a hierarchical and general Wi-Fi data processing and analysis framework to extract client travel activities from Wi-Fi log data. Wi-Fi log data collected from three communities in North Carolina- one university campus, the city of Wilson, and the town of Holly Springs, were processed and analyzed. Based on that, travel activities across different communities with specific Wi-Fi networks could be compared and analyzed to provide community human mobility and travel activity insights and the correlation between human travel and Wi-Fi network features.]]></description>
      <pubDate>Thu, 13 Feb 2025 17:25:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/2491361</guid>
    </item>
    <item>
      <title>ASAP: IEEE 802.11ax-based seamless access point handover for moving vehicles</title>
      <link>https://trid.trb.org/View/2410943</link>
      <description><![CDATA[The increasing number of connected and automated vehicles has led to a sharp increase in the demand for network access of moving vehicles. Although 5G networks support terminals with high mobility, the traffic load is too heavy to bear if all the vehicles have a large amount of data for transmission. Therefore, IEEE 802.11-based wireless network is a complementary offload solution to provide high-speed network access for vehicles with low cost, easy deployment and high scalability. However, frequent network handover of moving vehicles between multiple roadside access points (APs) results in network performance degradation, which is one of the challenges in vehicular communications. In this paper, the authors propose a framework (referred to as ASAP) based on the up-to-date IEEE 802.11ax standard to provide moving vehicles with seamless handover between multiple APs. By leveraging the high efficiency (HE) sounding protocol of IEEE 802.11ax, each AP is capable to monitor the current location of moving vehicles in real time. In addition, a mechanism is also proposed for AP uplink/downlink transmissions through collaboration between the APs and the backbone network to achieve seamless handover for moving vehicles. Since ASAP is based on IEEE 802.11ax, the compatible security scheme such as IEEE 802.11i can be applied to ASAP for security enhancement. The proposed solution does not require any modification on the user terminals, making it possible to be implemented in practice. Extensive simulations show that ASAP significantly reduces the network handover delay to microsecond level, and improves network throughput up to 59% compared with the state-of-the-art methods.]]></description>
      <pubDate>Tue, 22 Oct 2024 09:07:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/2410943</guid>
    </item>
    <item>
      <title>Empirical Models of Multiple Real Low-Cost 5.9GHZ Wi-Fi Interferers on IEEE 802.11P</title>
      <link>https://trid.trb.org/View/2335320</link>
      <description><![CDATA[There are new Wi-Fi channels in the 5.9GHz Dedicated Short Communications Band in the United States which once was licensed spectrum exclusively for IEEE 802.11p connected vehicle devices. Existing literature reports through simulations and modelling that unlicensed interference from low-cost Wi-Fi devices could degrade the quality of IEEE 802.11p communications. To date it has been challenging to perform experimentation at scale due to the lack of low-cost Wi-Fi devices that can actually transmit in the new 5.9GHz Wi-Fi channels. With this work the authors report the actual interference effects using 25 real low-cost devices which have been modified to operate in the new 5.9GHz Wi-Fi channels and report the effects on commercial IEEE 802.11p devices. Experimental observations show that infrastructure to vehicle messages have a higher likelihood of reception than vehicle to infrastructure messages during adjacent channel interference activity. The authors also provide empirical models for packet reception rate for connected vehicle messages for varying number of interferers. This work does not factor distance into the empirical models.]]></description>
      <pubDate>Sun, 18 Feb 2024 16:02:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/2335320</guid>
    </item>
    <item>
      <title>5.9GHz Interference Resiliency for Connected Vehicle Equipment</title>
      <link>https://trid.trb.org/View/2307543</link>
      <description><![CDATA[There are new Wi-Fi channels in the 5.9GHz Dedicated Short Communications Band in the United States which once was licensed spectrum exclusively for IEEE 802.11p connected vehicle devices. Existing literature reports through simulations and modelling that unlicensed interference from low-cost Wi-Fi devices could degrade the quality of IEEE 802.11p communications. Furthermore, the introduction of Wi-Fi 6e has presented an additional form of interference to C-V2X technology. To date it has been challenging to perform unlicensed interference experimentation at scale due to the lack of low-cost Wi-Fi devices that can transmit in the new 5.9GHz Wi-Fi channels and Wi-fi 6e channels. With this work the authors report the actual interference effects using 25 real low-cost devices which have been modified to operate in the new 5.9GHz Wi-Fi channels and Wi-fi 6e channels and report the effects on commercial DSRC and C-V2X devices. Experimental observations both in lab and in the field show that infrastructure to vehicle messages have a higher likelihood of reception than vehicle to infrastructure messages during adjacent channel interference activity.]]></description>
      <pubDate>Wed, 24 Jan 2024 16:55:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/2307543</guid>
    </item>
    <item>
      <title>Empowering Next-Generation IoT WLANs Through Blockchain and 802.11ax Technologies</title>
      <link>https://trid.trb.org/View/2211622</link>
      <description><![CDATA[Blockchain emerges as a potential solution for enabling distributed management and accountability of wireless Internet of Thing (IoT) networks. In addition, blockchain offers increased IoT security, as it involves every single node around the network to verify and approve new transactions. On the other hand, IEEE 802.11ax, a recently concluded WiFi standard aimed at achieving high network efficiency, plays a key role for solving spectrum sharing and cross-technology coexistence among WiFi and 6G cellular users, one of the key challenges faced by next-generation wireless systems. In this paper, the authors leverage the power of blockchain and 802.11ax technologies to propose a medium access control (MAC) protocol design for future IoT wireless local area networks (WLANs), also referred to as wireless IoT-Blockchain networks setup. Their simulation results show that the proposed protocol design enhances transmission latency and achievable network throughput.]]></description>
      <pubDate>Mon, 30 Oct 2023 16:54:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2211622</guid>
    </item>
    <item>
      <title>Adaptive Repetition Strategies in IEEE 802.11bd V2X Networks</title>
      <link>https://trid.trb.org/View/2201094</link>
      <description><![CDATA[Vehicle-to-everything (V2X) communications have very strict throughput and latency requirements, even in scenarios with high mobility. IEEE 802.11bd is being developed as a WiFi amendment to improve V2X performance, allowing up to three repetitions per packet, along with other features. Message repetitions increase time diversity and enable maximum ratio combining at the receiver, thus improving the probability of correct decoding. This paper investigates the IEEE 802.11bd packet repetition feature. First, we analyze how the increased channel load due to repetitions may in some cases result in a higher collision rate leading to lower network performance. Then, we propose two strategies for exploiting the IEEE 802.11bd repetition feature. The proposed strategies use the channel busy ratio to adapt the number of transmissions to the channel load and are validated through network-level simulations, which account for both the acquisition and decoding processes. Results show that the proposed strategies improve network performance under variable traffic conditions and enable fair access to the channel.]]></description>
      <pubDate>Fri, 23 Jun 2023 12:21:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2201094</guid>
    </item>
    <item>
      <title>Performance of Offloading Strategies in Collocated Deployments of Millimeter Wave NR-U Technology</title>
      <link>https://trid.trb.org/View/2118663</link>
      <description><![CDATA[5G New Radio (NR) technology operating in millimeter wave (mmWave) band is expected to be utilized in areas with high and fluctuating traffic demands such as city squares, shopping malls, etc. The latter may result in quality of service (QoS) violations. To deal with this challenge, 3GPP has recently proposed NR unlicensed (NR-U) technology that may utilize 60 GHz frequency band. In this paper, the authors investigate the deployment of NR-U base stations (BS) simultaneously operating in licensed and unlicensed mmWave bands in presence of competing WiGig traffic, where NR-U users may use unlicensed band as long as session rate requirements are met. To this aim, the authors utilize the tools of stochastic geometry, Markov chains, and queuing systems with random resource requirements to simultaneously capture NR-U/WiGig coexistence mechanism and session service dynamics in the presence of mmWave-specific channel impairments. The authors then proceed comparing performance of different offloading strategies by utilizing the eventual session loss probability as the main metric of interest. The authors' results show non-trivial behaviour of the collision probability in the unlicensed band as compared to lower frequency systems. The baseline strategy, where a session is offloaded onto unlicensed band only when there are no resources available in the licensed one, leads to the best performance. The offloading strategy, where sessions with heavier-than-average requirements are immediately directed onto unlicensed band results in just $2\!-\!5\%$ performance loss. The worst performance is observed when sessions with smaller-than-average requirements are offloaded onto unlicensed band.]]></description>
      <pubDate>Wed, 22 Feb 2023 09:53:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/2118663</guid>
    </item>
    <item>
      <title>A Novel MIMO-OFDM Based MAC Protocol for VANETs</title>
      <link>https://trid.trb.org/View/2059274</link>
      <description><![CDATA[Vehicular ad hoc networks (VANETs) have recently become more significant to intelligent transport systems (ITS). Recent works focused on improving throughput and decreasing delay. In this paper, a novel MIMO-OFDM based MAC Protocol is proposed for VANETs to enhance their performance. Multiple-input multiple-output (MIMO) and orthogonal frequency division multiplexing (OFDM) are integrated to exploit the benefit of both MIMO and OFDM. To accord MIMO with OFDM, a novel access mechanism is proposed. 3D Markov chain model-based analytical study is presented, considered a non-saturated condition. Nakagami-m fading channels are taken into account in the study. Parameters affecting performance are taken into consideration, and relationships are derived. The probability of successful transmission, probability of outage, bit error rate (BER), throughput, and delay expressions are achieved. Moreover, numerical results are presented, which verify analytical studies.]]></description>
      <pubDate>Tue, 24 Jan 2023 09:29:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/2059274</guid>
    </item>
    <item>
      <title>Utilizing Wi-Fi Sensing and an Optimized Radius Algorithm to Count Passengers with Transfers to Enhance Bus Transit O-D Matrix</title>
      <link>https://trid.trb.org/View/1969882</link>
      <description><![CDATA[The origin and destination (O-D) of public transit passengers are important for the planning and operation of the transit system. However, only 46% of public transit agencies have a smart card system in the US, and most of them require an entry-only tap, which prohibits identifying passenger destinations unless utilizing an estimation model. Therefore, there is a need for a cost-effective and automated solution to facilitate the majority of the US transit agencies in recognizing the origin and destination of passengers as well as capturing passenger transfers. This paper created a novel algorithm for transit agencies to count passengers with the consideration of transfers using a cost-effective Wi-Fi sensing–based approach. Two pilot studies were conducted in the city of Louisville, Kentucky on three different bus routes to explore the feasibility of the method. A Wi-Fi detector was installed in the bus to detect passengers, and a manual counting was performed to be used as ground truth data. After data collection, the proposed algorithms were applied to optimize the detection radius and to eventually find origins, destinations, and transfers. Analysis revealed that the proposed Wi-Fi–based approach is capable of recognizing 78.7% of the total passengers as well as detecting their boarding and alighting activities. The paper demonstrates the ability of the proposed method to detect passengers with a reasonable detection rate by using Wi-Fi technology on bus routes, which makes it feasible for transit agencies to conduct frequent and low-cost network-level passenger O-D studies.]]></description>
      <pubDate>Wed, 27 Jul 2022 14:29:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/1969882</guid>
    </item>
    <item>
      <title>Steering model identification and control design of autonomous ship: a complete experimental study</title>
      <link>https://trid.trb.org/View/1956472</link>
      <description><![CDATA[Steering ship models are important for the study of autonomous ship manoeuverability and design of ship motion control system. It is always a difficult task to find the mathematical model by first principle as it needs prior knowledge of hydrodynamic derivatives. The input–output-based system identification theory can be used to establish system mathematical models. A solution is offered by developing a Wi-Fi-based self-propelled, autonomous system for a ship model with Internet of Things (IoT) capabilities to perform manoeuvering and seakeeping tests in indoor environment without any complex mechanical structure, viz. following bridge. The developed autonomous on-board system equipped with main computer, suitable electronics, sensors, data acquisition system and Wi-Fi-based communication system. The developed system offers a cost effective, modular and portable solution to perform hydrodynamic studies of different hull form without incorporating major changes in the system. The use of IoT makes the data accessible to a naval architecture in real-time to analyse the motion response of the ship in different wave conditions and enables to implement the digital twin to simulate the real field scenario. Input–output-based model identification experiments such as turning circle and zig-zag tests are conducted to estimate the first-order steering model parameters and is further extended to design and implementation of a classical proportional–derivative-based steering control. The design is described in this paper with details of implementation on a demonstration oceanographic coastal research vessel. It illustrates the excellent communication between shore station computer and the on-board system on a wire-free model with robust control and exhibiting all the motion behaviour and dynamic effects. Experiments performed in wave basin in different wave conditions validate the efficacy of the proffered method.]]></description>
      <pubDate>Thu, 30 Jun 2022 09:42:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/1956472</guid>
    </item>
    <item>
      <title>User Community Identification Through Fine-Grained Mobility Records for Smart City Applications</title>
      <link>https://trid.trb.org/View/1948131</link>
      <description><![CDATA[Motivated by Smart City applications and services, this article presents a novel approach to identifying <i>user communities</i> in communication networks.The authors define user communities as groups of users that share common mobility features over spatio-temporal scales of arbitrary length, such as time spent in certain locales, mobility speed, and time between consecutive movements. They describe their user community identification framework in detail including how mobility features can be extracted from real mobility traces (as examples of unlabelled data) and synthetic mobility records (as examples of labeled data). They present results obtained when using their approach in four distinct mobility scenarios represented by both unlabeled and labeled datasets. The authors also introduce a new validation methodology that uses image-based similarity metrics in order to assess the quality of identified communities. Their results show that the proposed approach significantly increases similarity between users within the same community as well as dissimilarity between users in different communities. They also demonstrate that the proposed user community identification approach yields significant increase in contact time amongst users belonging to the same community when compared to the average contact time when not considering community structures.]]></description>
      <pubDate>Mon, 27 Jun 2022 17:19:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/1948131</guid>
    </item>
    <item>
      <title>Ethernet in the Control Path: Time-Critical Services Using Modern Networking Technology</title>
      <link>https://trid.trb.org/View/1828372</link>
      <description><![CDATA[Traditional IT-based networks, such as Ethernet, have been poor choices in the past for automotive use. In particular, the lack of deterministic (and small) delays has prevented Ethernet from making significant inroads into control systems. Various proprietary systems based on Ethernet components have shown that it is possible to architect such networks, but until very recently, there were no standards to guarantee interoperability. Fortunately, the IEEE 802 working groups have been developing new specifications to enable “time sensitive networks” that are interoperable, compatible with existing IT networks, and that will meet the requirements of automotive and industrial control systems. This paper will outline the technology behind the new specifications and describe how they can be used to build unified automotive networks for both control and infotainment applications. Compatibility and coexistence with CAN and FlexRay will also be discussed.]]></description>
      <pubDate>Tue, 24 May 2022 10:09:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/1828372</guid>
    </item>
    <item>
      <title>Correlating The Mac Address With The Passenger: Wi-Fi Scanner Survey On Paratransit Mode</title>
      <link>https://trid.trb.org/View/1930497</link>
      <description><![CDATA[Origin-destination (OD) information is very useful for transportation management and planning. OD provides a detail information about traffic volume or passenger volume for each zone in the area. In developing countries, the paratransit mode produces varied OD data daily because it has stops at irregular nodes and times. This research uses Wi-Fi technology in to capture media access control (MAC) address passenger data during paratransit service. The objective of this study is to make OD or boarding alighting data based on Wi-Fi estimated. The result showed some characteristics and/or similarities with dates or routes. A high correlation is shown on all days for the Antang route (0.85) and on August 27, 2018, for the Antang route (0.79). For the accuracy of each Wi-Fi device result, A high correlation was obtained for the Antang, Cendrawasih, Daya, and Panampu routes.]]></description>
      <pubDate>Tue, 24 May 2022 10:08:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/1930497</guid>
    </item>
    <item>
      <title>Comparative Analysis of a Vehicular Safety Application in NS-3 and Veins</title>
      <link>https://trid.trb.org/View/1901145</link>
      <description><![CDATA[Vehicular communications based on IEEE802.11p promise to improve traffic efficiency and safety in the near future. Embedded with 802.11p-compliant devices, the cooperation among connected vehicles will provide a shift in the way transportation systems operate. Nevertheless, before widespread adoption, extensive performance evaluation of the standard is in need. Due to the high cost and reasonably low availability of commercial devices, most work on VANETs is still performed using simulations. To investigate the equivalence between real experiments and simulations involving 802.11p, this article evaluates the behavior obtained by periodic beacon messages, the basis of safety applications in VANETs. Using commercial OBUs and RSUs, the results are compared with those obtained with NS-3/PhySim and Veins/MiXiM simulators. In V2I and V2V communication scenarios, three key metrics are evaluated: the maximum communication range, packet delivery rate, and packet inter-reception time. The influence of different modulations supported by 802.11p and varying vehicle speeds are also analyzed.]]></description>
      <pubDate>Mon, 25 Apr 2022 17:02:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/1901145</guid>
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