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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
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    <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>A staged wildfire evacuation model for wildland-urban interface communities with transient populations</title>
      <link>https://trid.trb.org/View/2562596</link>
      <description><![CDATA[The wildland-urban interface (WUI) communities with transient populations (e.g., second homeowners and visitors) can experience significant travel demand on weekends or holidays, which poses a major challenge for community wildfire evacuation planning. However, relevant research on the use of staged evacuation in wildfire evacuation planning for such WUI communities is still scarce. This study aims to utilize predefined evacuation zones (PEZs) and the Multi-Agent Transport Simulation (MATSim) package to develop and test a new staged wildfire evacuation model for WUI communities with transient populations. The proposed model uses different types of data (e.g., residential parcels, household vehicle ownership, second-home occupancy rates, Genasys zones, and OpenStreetMap roads) as inputs and can derive evacuation time estimates (ETEs), traffic counts on the road links, and individual travel times as outputs. The authors used the Tahoe Donner community in Truckee, California to demonstrate the effectiveness of the model. The results show that staged evacuation can significantly reduce traffic congestion near the fire front compared to simultaneous evacuation. The model can help incident commanders gain a better understanding of how to use PEZs in wildfire evacuation to create more effective community evacuation plans.]]></description>
      <pubDate>Wed, 20 Aug 2025 11:57:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2562596</guid>
    </item>
    <item>
      <title>Experimental Approach to Water Hammer Phenomenon</title>
      <link>https://trid.trb.org/View/2407961</link>
      <description><![CDATA[The paper indicates the frequent occurrence of transient states in hydraulic systems. Particular attention was paid to the phenomenon of water hammer - the causes and effects of this phenomenon. The necessity to modify the theoretical description of this phenomenon was indicated. The work focuses on the presentation of the development of the structure of experimental stands to study the phenomenon of water hammer. The research results obtained on the presented experimental stands were used to verify the theoretical considerations presented in other papers by the authors. The presented successive concepts of the test stand enable the research to be carried out to a greater extent and at the same time eliminate the disadvantages of the previous versions of the test stand. The stand presented as the final one also allows the testing of transients in hydraulic lines for various types of working fluid (oil, emulsion, distilled water).]]></description>
      <pubDate>Wed, 20 Nov 2024 13:08:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2407961</guid>
    </item>
    <item>
      <title>A New Method for Fault Location of Metro Traction Network Based on Transient Ratio Method</title>
      <link>https://trid.trb.org/View/1975830</link>
      <description><![CDATA[When the rail short-circuit fault occurs in the traction network of the railway, especially when the traction network is short-circuited through a large transition resistance or the fault occurs near the substation, the existing fault location methods often have larger error. Compared with traveling wave method and artificial intelligence-based fault location method, the two-terminal synchronous fault analysis method is more suitable for fast and accurate short-circuit fault location of metro traction network. Steady-state ratio method is derived from the steady-state of fault analysis method. However, due to the influence of post-fault protection tripping, the synchronous acquisition of steady-state values at both ends cannot be guaranteed. A new fault location method based on transient ratio method is proposed to solve the problem of low accuracy of existing fault location methods for metro traction network. Compared with the traditional fault analysis method and the steady-state ratio method, this method does not need the synchronization of two-terminal data and is not affected by the protection tripping after the fault occurs. Fault location can be realized by using the ratio of initial short-circuit current on both sides of fault point. The simulation results by MATLAB/Simulink show that this method is less affected by the inaccurate estimation of transition resistance and traction network parameters. The method is simple and accurate and has a certain application prospect.]]></description>
      <pubDate>Fri, 23 Aug 2024 16:53:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/1975830</guid>
    </item>
    <item>
      <title>A Novel Quasi-Dimensional Model for Transient Mixing Prediction in Two-Phase Multicomponent Sprays under Flash-Boiling Conditions</title>
      <link>https://trid.trb.org/View/2367851</link>
      <description><![CDATA[A novel one-dimensional multiphase and multicomponent spray model - hereafter referred to as the Kattke-Weigand model - has been developed to predict the penetration length of both vapor and liquid gasoline sprays under flash-boiling conditions, such as superheated injections. Its formulation is based on mass and momentum equations for unsteady jets and is therefore capable of capturing dynamic effects. Experiments were conducted in a constant volume chamber using various ambient and fuel temperature conditions and a six-hole GDI injector with a separated jet. Macroscopic spray parameters were extracted from the measurements to verify the model's ability to predict both liquid and vapor penetration length and the corresponding spray angles.Apart from the separated jet of the injector used, the other five jets interact strongly with each other under flash boiling conditions, resulting in spray collapse, and thus affecting spray characteristics. The prediction of collapse is very sensitive to calculations of vaporization and air entrainment. Since these submodels cannot be validated directly, a calibration method was developed, that is based on a three-dimensional reconstruction of all fuel sprays of the injector used. For this purpose, all optical measurements performed in the constant volume chamber are utilized. As a result, a three-dimensional representation of the spray collapse can be calculated from the combination of the 3D spray reconstruction and the entrainment and vaporization submodels. The validation of the collapse leads indirectly to the calibration of the entrainment and vaporization submodels in the Kattke Weigand model. Latter is applied to gain a deeper understanding of the interaction between spray collapse and both liquid and vapor phase penetration.]]></description>
      <pubDate>Thu, 25 Apr 2024 09:33:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2367851</guid>
    </item>
    <item>
      <title>Activity Space Investigations for Nonresidents Using Mobile Phone Data</title>
      <link>https://trid.trb.org/View/2000453</link>
      <description><![CDATA[The transportation integration of in urban areas is the main direction of urban development. The regions in Shanghai have strong connection with the Yangtze River Delta mega-city group. This paper analyzes the activity space of nonresidents by using mobile phone data. An identification method has been used to identify nonresidents traveled through the Hongqiao transportation hub for air flights or high-speed trains. After identifying active areas of nonresidents, POI data is introduced to evaluate the built environment to quantify activity space by using the factor analysis method. Three activity space indicators have been proposed to describe the activity space. By using a two-step clustering method, nonresidents are classified into four clusters to better describe their activity space. The result shows that the activity space of nonresidents was distributed in a way that has strong relationship with Metro Line 2, which can strongly support the further connections between Shanghai and the Yangtze River Delta mega-city group.]]></description>
      <pubDate>Mon, 27 Mar 2023 15:09:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2000453</guid>
    </item>
    <item>
      <title>Load Case Characterization and Modal Coordinate Estimates from Damper Displacements</title>
      <link>https://trid.trb.org/View/1802084</link>
      <description><![CDATA[This paper evaluates estimations of modal coordinates from chassis damper displacements on heavy vehicles. The objective is to study to what extent relative displacements are sufficient as control input for semi active damping systems. The possibility to combine passive damping requirements at different driving conditions is furthermore investigated by studying damper displacements in the phase plane. For both objectives, vehicle simulations with a 3D - tractor semi trailer model are utilized. Results show that modal coordinate estimates based solely on relative damper displacements, during impact for transient load cases show significant discrepancies to actual motion. For subsequent free oscillations, modal coordinates may however be estimated this way. Phase plane plots are finally shown to be useful tools to illustrate conflicting demands on passive damping characteristic and to rate expected benefits from different damper techniques.]]></description>
      <pubDate>Mon, 29 Aug 2022 11:32:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/1802084</guid>
    </item>
    <item>
      <title>EGR Response in a Turbo-charged and After-cooled DI Diesel Engine and Its Effects on Smoke Opacity</title>
      <link>https://trid.trb.org/View/1815983</link>
      <description><![CDATA[Three thermo-wires with amplifying circuits have been developed to measure the time-resolved concentration of the exhaust gas recirculated into the intake manifold by a rotary valve-based exhaust gas recirculation (EGR) system of a diesel engine. Good agreement was found between the EGR rates measured by the temperature based system and a conventional CO₂ tracing system. The developed EGR measuring system was used to investigate the EGR transient response in a turbo-charged and after-cooled diesel engine with a real-time measure and control system. The EGR response under EGR valve step change and engine transient operating conditions are discussed. At first, the engine was running under a certain steady condition with zero recirculated exhaust gas, then the rotary valve opened to maximum within 0.1s to demonstrate the EGR step change behavior. EGR rate and air intake stabilized in 0.5s. The combustion process characterized by the maximal in-cylinder pressure came to stabilization in 1.9s. Because of the in-cylinder thermal lag and combustion fluctuations the transient smoke opacities were much different from those at constant EGR rate operation and increased gradually to stabilization in approximately 5s. So, when EGR system is adopted to realize HCCI combustion this performance lag must to be taken into consideration.  The engine typical transient operations named constant speed and increasing torque (CSIT) operations, were realized by evenly boosting the accelerator so as to make the engine increase torque from 100N·m to 500N·m at constant 1600 rpm. Test results showed that the sudden decrease in air intake (resulted by the turbo-lag) brought a dramatic increase of the pressure drop across the EGR valve and resulted in greater EGR rate which deteriorated the smoke opacity under transient operations. The peak smoke opacity under 16CSIT5 operation (constant 1600 rpm from initial 100N·m to final 500N·m within 5s) with the EGR system controlled by the steady-operation strategies was 3 times that of an engine without EGR. In order to obtain better transient performance of the diesel engine equipped with the EGR, its control strategy must be optimized.]]></description>
      <pubDate>Tue, 23 Aug 2022 09:11:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/1815983</guid>
    </item>
    <item>
      <title>Computation of Energy Absorption and Residual Voltage in a Fourth Rail LRT Station Arresters in EMTP-RV: A Comparative Study</title>
      <link>https://trid.trb.org/View/1854114</link>
      <description><![CDATA[This paper presents a study on the performance of a fourth rail direct current (DC) urban transit affected by an indirect lightning strike. The indirect lightning strike was replicated and represented by a lightning-induced overvoltage by means of the Rusck model, with the sum of two Heidler functions as its lightning channel base current input, on a perfect conducting ground. This study aims to determine whether an indirect lightning strike has any influence with regard to the performance of the LRT Kelana Jaya line, a fourth rail DC urban transit station arrester. The simulations were carried out using the Electromagnetic Transients Program–Restructured Version (EMTP–RV), which includes the comparison performance results between the 3EB4-010 arrester and PDTA09 arrester when induced by a 90 kA (9/200 µs). The results demonstrated that the PDTA09 arrester showed better coordination with the insulated rail bracket of the fourth rail. It allowed a lower residual voltage and a more dynamic response, eventually resulting in better voltage gradient in the pre-breakdown region and decreased residual voltage ratio in the high current region.]]></description>
      <pubDate>Wed, 17 Nov 2021 14:25:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/1854114</guid>
    </item>
    <item>
      <title>Observing transient behavior during Hurricane Sandy through passively collected data</title>
      <link>https://trid.trb.org/View/1658731</link>
      <description><![CDATA[Transients, such as tourists or business travelers, often fly into large cities and subsequently have to rely on public transportation for movement within the city. It is difficult to observe transient behavior in the event of a disaster through traditional survey methods. Thus, transient behavior has not been understood as well as resident behavior, which presents a challenge to emergency management. This study used taxi trip records that are passively collected year-round in New York City (NYC) to observe transient behavior during Hurricane Sandy (2012). The linkage between transients and taxi trips was built upon the fact that many transients choose hotels as accommodation and depend on taxis during their travel in NYC. This study extracted and analyzed taxi trips originating from hotels shortly before and after the hurricane landfall, which cover transient outbound activities in a week. In the pre-landfall period, it was found that transients who evacuated out of Manhattan were more likely to leave hotels about 18–24 h before hurricane landfall; and those who stayed made more shopping trips within Manhattan. In the post-landfall period, transients were more likely to relocate on the second day after hurricane landfall; some transients headed to local airports once limited service was resumed. This is believed to be the first study to use passively collected data to observe transient travel behavior in the event of a hurricane as well as on normal days.]]></description>
      <pubDate>Thu, 14 Nov 2019 09:30:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/1658731</guid>
    </item>
    <item>
      <title>Observing transient behavior during Hurricane Sandy through passively collected data</title>
      <link>https://trid.trb.org/View/1573318</link>
      <description><![CDATA[Transients, such as tourists or business travelers, often fly into large cities and subsequently have to rely on public transportation for movement within the city. This presents a challenge to evacuation in the event of a disaster. However, it is difficult to observe transient behavior through traditional survey methods. Thus transient behavior has not been understood as well as resident behavior. This study used taxi trip records that are passively collected year-round in New York City (NYC) to observe transient behavior during evacuation. The linkage between transients and taxi trips was built upon the fact that many transients choose hotels as accommodation and depend on taxis during their travel in NYC. This study extracted all taxi trip records originating from hotels in a short time before the landfall of Hurricane Sandy (2012) and analyzed their characteristics. It was found that transients who evacuated out of Manhattan were more likely to leave hotels about 18 to 24 hours before the hurricane landfall; and those who stayed made more shopping trips within Manhattan. This is believed to be the first study to use passively collected data to observe transient travel behavior in both the event of a hurricane as well as on normal days.]]></description>
      <pubDate>Fri, 01 Mar 2019 15:51:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/1573318</guid>
    </item>
    <item>
      <title>Local leadership and community matter: Establishing a transit station for exiting disaster survivors</title>
      <link>https://trid.trb.org/View/1517547</link>
      <description><![CDATA[This paper describes the experience of a municipality in the Philippines which became a transient station for disaster survivors seeking to move out of the area heavily affected by the 2013 Typhoon Haiyan-TY Surge. More specifically, it aims to examine the driving factors enabling the local government to provide relief services and explores the role of transport system in ensuring the mobility of people after a disaster. After typhoon Haiyan, there was a sudden surge of survivors moving to areas where sea transportation is available. One such area is the Municipality of Hilongos. The presence of transient survivors in the municipality moved its local government to provide relief assistance without prior preparations. The experience of Hilongos offers several insights regarding the nature of disaster spillover effects and the potential role of a nearby local government in providing assistance to areas stricken by a disaster. It also highlights the role of the transport sector in providing services during emergency disaster situation. Data for this paper were culled from the secondary data and key informant interviews with government officials as well as an FGD with the Quick Response Team of Hilongos Municipal Disaster Risk Reduction Office. The experience of the local government of Hilongos suggests the need to craft a holistic, systemic, and collaborative approach in dealing with disaster-related effects or outcomes.]]></description>
      <pubDate>Thu, 19 Jul 2018 14:45:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/1517547</guid>
    </item>
    <item>
      <title>Cross Winds and Transients: Reality, Simulation and Effects</title>
      <link>https://trid.trb.org/View/1431554</link>
      <description><![CDATA[This paper provides a published counterpart to the address of the same title at the 2010 SAE World Congress.         A vehicle on the road encounters an unsteady flow due to turbulence in the natural wind, due to the unsteady wakes of other vehicles and as a result of traversing through the stationary wakes of road side obstacles. This last term is of greatest significance.         Various works related to the characterization, simulation and effects of on-road turbulence are compared together on the turbulence spectrum to highlight differences and similarities. The different works involve different geometries and different approaches to simulating cross wind transients but together these works provide guidance on the most important aspects of the unsteadiness.         On-road transients include a range of length scales spanning several orders of magnitude but the most important scales are in the in the 2-20 vehicle length range. There are significant levels of unsteadiness experienced on-road in this region and the corresponding frequencies are high enough that a dynamic test is required to correctly determine the vehicle response. Fluctuations at these scales generate significant unsteady loads (aerodynamic admittance typically 0.6-1.4) and the corresponding frequencies can adversely affect vehicle dynamics.         The generation of scales larger than the scale of the vehicle is impractical with passive grids and so active turbulence generation systems are preferred. These can be classified into lift and drag-based devices. Lift-based devices provide better control of the turbulence but can only just reproduce the smaller scales in the 2-20 vehicle length range. Different moving model approaches are also discussed. CFD offers real advantages through its ability to allow arbitrary time-varying boundary conditions.       ]]></description>
      <pubDate>Tue, 02 Jan 2018 10:39:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/1431554</guid>
    </item>
    <item>
      <title>Metrics for the Rapid Assessment of Transient Severity in Pipelines</title>
      <link>https://trid.trb.org/View/1366210</link>
      <description><![CDATA[Concepts relating to energy transformations within built and natural systems have been some of the most fruitful in the history of science and engineering. The property of energy summarizes essential changes both in a system’s state and key interactions with its environment. Traditional unsteady flow analyses, based on momentum and continuity relations, have been dominated by considerations of wave mechanics, such as unsteady fluid friction which is typically accommodated via adjustments to the momentum equation. The current paper demonstrates how conventional analyses can be supplemented with metrics that can provide a complementary understanding of transient flows. Specifically, this study considers the classical Joukowsky equation, mass oscillations, and the role of energy in analyzing the performance of transient protection devices. The goal is to gain insight by considering energy transformations and interactions.]]></description>
      <pubDate>Fri, 25 Sep 2015 16:19:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/1366210</guid>
    </item>
    <item>
      <title>Transient Analysis of the Gas-Liquid Two Phase Flow in Long-Distance Water Pipelines</title>
      <link>https://trid.trb.org/View/1275062</link>
      <description><![CDATA[In a long distance pipeline, the trapped air usually resides at the dead ends and the segments of pipes with the high elevations because the air cannot exhaust smoothly. When the pump shuts off or the valve is closed suddenly, the water hammer with gas-liquid two-phase flow will occur. The pressure resulting from the gas-liquid two-phase transient flow will be much bigger than that from the general water hammer. It is one of the major factors to result in pipe burst. The objective of this paper is to study the gas-liquid two phase transient flow in the pressure pipeline. The research achievement is applied in an actual engineering project. Firstly, the control equations of the gas-liquid two phase transient flow in pressure pipelines are presented based on the gas-liquid two phase flow theory and computational fluid dynamics. Then, by means of volume of fluid (VOF) model, the flow field around the trapped air in pipelines is numerical simulated and analyzed on the stages of water filling and pump failure. The pressure fluctuation around the trapped air is obtained. Finally, the research achievement is applied to an actual long distance pipeline. The results show that the VOF model could effectively simulate the flow fields of the gas-liquid two phase transient flow. On the stage of water filling, the maximum pressure head decreases with the increase of the valve opening duration. When the pump shuts off suddenly, the maximum pressure head rises up with the increase of the pipe slope in which the trapped air exists.]]></description>
      <pubDate>Wed, 30 Apr 2014 10:12:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/1275062</guid>
    </item>
    <item>
      <title>Transient Analysis of Gas Networks Based on the Method of Characteristics with Inertial Multiplier</title>
      <link>https://trid.trb.org/View/1275061</link>
      <description><![CDATA[Hydraulic analysis of steady state conditions is typically used in the design and operation of gas networks. However, operational gas network systems are never in the steady state as demands and pressures vary with time. By comparison, transient analysis is more valuable and helpful for engineering design and operational management. The method of characteristics (MOC) is often used to analyze the transient flow of gas networks because it has clear physical concepts and employs rigorous mathematical analysis and precision in calculation. However, with MOC a small time step has to be included for an accurate result, which costs a lot of computing time. In this paper, it is shown that the MOC with an inertial multiplier is capable of providing a numerical simulation of the transient flow in gas networks. After the inertial multiplier is established, then the transient flow for a gas network system is numerically simulated. Two simulation outcomes are compared, one using the MOC and another the MOC with an inertial multiplier. Results show that the time step can be selected flexibly and the computational speed can be reduced by means of the MOC with an inertial multiplier. The MOC with an inertial multiplier is more efficient for transient analysis of gas networks than the MOC alone.]]></description>
      <pubDate>Wed, 30 Apr 2014 10:12:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/1275061</guid>
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