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    <title>Transport Research International Documentation (TRID)</title>
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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>
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      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Analytical Performance of Direct-Hydrogen-Fueled Polymer Electrolyte Fuel Cell (PEFC) Systems for Transportation Applications</title>
      <link>https://trid.trb.org/View/1862866</link>
      <description><![CDATA[The performance of a stand-alone polymer electrolyte fuel cell (PEFC) system directly fueled by hydrogen has been evaluated for transportation vehicles. The study was carried out using a systems analysis code and a vehicle analysis code. The systems code includes models for the various PEFC components and is applicable for steady-state and transient situations. At the design point, the system efficiency is above 50% for a 50-kW system. The efficiency improves under partial load and approaches 60% at 40% load as the fuel cell operating point moves to lower current densities on the V-I polarization curve. At much lower loads, the system efficiency drops because of the deterioration in the performance of the compressor, expander, and eventually the fuel cell. The results of the transient analysis indicate that the PEFC system can start rapidly from ambient temperatures (300 K). The PEFC system has been evaluated for near-term and future mid-size vehicles. The results of the study show that the PEFC system can meet the demands of the Federal Urban Driving Schedule (FUDS) and the Highway driving cycles, for both warm and cold start-up conditions. The results also indicate that the future PEFC vehicle can meet the fuel economy goal of 80 miles per gallon (mpg) equivalent,]]></description>
      <pubDate>Mon, 25 Oct 2021 17:57:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/1862866</guid>
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    <item>
      <title>Development of households’ vehicle choice models for travel accompanying arrangements</title>
      <link>https://trid.trb.org/View/1850148</link>
      <description><![CDATA[This study examines the vehicle choice behavior of multicar households for different travel accompanying arrangements. It investigates the influence of various travel attributes and neighborhood characteristics to understand how individuals in a multicar household make a choice of vehicle for a specific travel arrangement. The study considers three types of travel arrangements based on accompanying persons (i.e. alone, with household members and with non-household members) and categorizes households’ vehicle fleet into six classes: subcompact, compact, midsize, SUV, vans/minivans/pickup-trucks and luxury vehicles. Three flexible latent class logit models (LCLMs) are developed in this study to estimate vehicle choice decisions by utilizing data from the ‘2015 Nova Scotia Travel Activity (NovaTRAC) survey’. Results suggest that individuals tend to prefer subcompact vehicles and SUVs for longer travel time while traveling alone and with non-household members, respectively. They show higher likelihood to choose midsize vehicles for long-distance trips when traveling with household members. The behavioral models also capture unobserved heterogeneity across population by developing flexible class allocation models within LCLM frameworks that probabilistically distribute individuals into discrete latent classes based on their socio-demographic characteristics. Model results intuitively suggest two latent classes for all three travel arrangements and explore heterogeneity across classes. Results of this study will assist the transportation planners and policymakers to develop alternative transportation demand management strategies that aim at reducing vehicular emission and energy in a traffic network.]]></description>
      <pubDate>Thu, 24 Jun 2021 16:43:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/1850148</guid>
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      <title>Occupant Kinematics and Injury Response in Steer Maneuver-Induced Furrow Tripped Rollover Testing</title>
      <link>https://trid.trb.org/View/1779067</link>
      <description><![CDATA[Occupant kinematics during rollover motor vehicle collisions have been investigated over the past thirty years utilizing Anthropomorphic Test Devices (ATDs) in various test methodologies such as dolly rollover tests, CRIS testing, spin-fixture testing, and ramp-induced rollovers. Recent testing has utilized steer maneuver-induced furrow tripped rollovers to gain further understanding of vehicle kinematics, including the vehicle's pre-trip motion. The current study consisted of two rollover tests utilizing instrumented test vehicles and instrumented ATDs to investigate occupant kinematics and injury response throughout the entire rollover sequences, from pre-trip vehicle motion to the position of rest. The two steer maneuver-induced furrow tripped rollover tests utilized a mid-sized 4-door sedan and a full-sized crew-cab pickup truck. The pickup truck was equipped with seatbelt pretensioners and rollover-activated side curtain airbags (RSCAs). The RSCAs were a prototype next generation design. The sedan was not equipped with these technologies. Each test vehicle contained two restrained instrumented 50th-percentile male ATDs in the front outboard seating positions. The vehicles were accelerated using a tow system, released, and then maneuvered onto a dirt test surface by an automated steering controller resulting in a passenger-side-leading soil-tripped rollover. The RSCAs and seatbelt pretensioners in the pickup truck deployed prior to the first vehicle-to-ground contact. Occupant kinematics and ATD injury metrics were evaluated for the duration of the roll events. The results of the study demonstrated two neck-loading events wherein the compressive loads in the upper neck and the Nij were well in excess of the Injury Assessment Reference Values (IARV). Both of these neck-loading events involved the driver ATD in the sedan. The vertical deformation of the driver side roof structure at the time of the first neck-loading event that exceeded the IARV was 4.4 cm (1.7 inches). The second of these events involved direct head-to-ground contact. Compressive neck loading events were preceded by a pattern of a peak in the filtered axial head acceleration, followed by a peak in the filtered axial chest acceleration A statistically significant positive correlation was observed between axial chest acceleration and axial compressive neck force. The interaction of the RSCAs with the two ATDs in the pickup truck was also investigated. The ATD loading and airbag interaction differed between the leading-side and trailing-side of the pickup truck. Occupant ejection was not observed to occur in this test. Both tests showed multiple incidences when the occupants' heads were in proximity to the roof. The current study provides insight into occupant kinematics and injury potential during steer maneuver-induced furrow tripped rollover events, including the effects of RSCAs and seatbelt pretensioners.]]></description>
      <pubDate>Mon, 03 May 2021 11:49:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/1779067</guid>
    </item>
    <item>
      <title>Development of New Hybrid Transaxle for Mid-Size Sports Utility Vehicles</title>
      <link>https://trid.trb.org/View/1701868</link>
      <description><![CDATA[Toyota has developed a new Hybrid (HV) transaxle P810 for Mid-Size SUVs to improve fuel efficiency and power performance. The transaxle was developed based on Toyota's new development strategy - Toyota New Global Architecture (TNGA). By adopting technologies to shorten overall length of the transaxle, installation into the same engine compartment of Mid-Size sedans have been realized while also improving the motor output. This paper will introduce technologies regarding the new mount structure for shortening overall length, and furthermore, noise reduction related to this mount structure.       ]]></description>
      <pubDate>Fri, 15 May 2020 11:07:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/1701868</guid>
    </item>
    <item>
      <title>Development of New Hybrid System for Mid-Size SUV</title>
      <link>https://trid.trb.org/View/1701865</link>
      <description><![CDATA[Fuel economy and emission regulations for Light-duty Trucks (LDT) are becoming increasingly restrictive year by year. At the same time, Mid-size SUV demands are increasing all over the world. The advancement of Toyota Hybrid System (THS) aims to meet increasingly strict fuel economy regulations and rapidly advance vehicle technologies to meet electrification goals by 2050 (Figure 1). Toyota has been committed to the evolution of hybrid technology starting with the first Prius in 1997 and continues to develop industry leading electrification technologies. The updated hybrid system for the brand-new Highlander was developed to meet worldwide regulations and have competitive class leading fuel economy with an affordable price. This technology is necessary not only to anticipate expanding SUV sales around the world, but to also keep environmental impact to a minimum. This paper explains the performance and technology in the updated THS developed for the brand-new Highlander HV 2.5L E-Four and highlights environmental and performance comparisons to the MY2019 RAV4 HV and the previous generation Highlander HV.       ]]></description>
      <pubDate>Fri, 15 May 2020 11:07:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/1701865</guid>
    </item>
    <item>
      <title>Trends in life cycle greenhouse gas emissions of future light duty electric vehicles</title>
      <link>https://trid.trb.org/View/1691083</link>
      <description><![CDATA[The majority of previous studies examining life cycle greenhouse gas (LCGHG) emissions of battery electric vehicles (BEVs) have focused on efficiency-oriented vehicle designs with limited battery capacities. However, two dominant trends in the US BEV market make these studies increasingly obsolete: sales show significant increases in battery capacity and attendant range and are increasingly dominated by large luxury or high-performance vehicles. In addition, an era of new use and ownership models may mean significant changes to vehicle utilization, and the carbon intensity of electricity is expected to decrease. Thus, the question is whether these trends significantly alter expectations of future BEV LCGHG emissions.To answer this question, three archetypal vehicle designs for the year 2025 along with scenarios for increased range and different use models are simulated in an LCGHG model: an efficiency-oriented compact vehicle; a high performance luxury sedan; and a luxury sport utility vehicle. While production emissions are less than 10% of LCGHG emissions for today’s gasoline vehicles, they account for about 40% for a BEV, and as much as two-thirds of a future BEV operated on a primarily renewable grid. Larger battery systems and low utilization do not outweigh expected reductions in emissions from electricity used for vehicle charging. These trends could be exacerbated by increasing BEV market shares for larger vehicles. However, larger battery systems could reduce per-mile emissions of BEVs in high mileage applications, like on-demand ride sharing or shared vehicle fleets, meaning that trends in use patterns may countervail those in BEV design.]]></description>
      <pubDate>Tue, 21 Apr 2020 10:11:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/1691083</guid>
    </item>
    <item>
      <title>The Adaptive Cycle Engine on Standard Duty Cycles</title>
      <link>https://trid.trb.org/View/1598321</link>
      <description><![CDATA[Continuing research introduced at the 2018 WCX conference, this paper shows the result of simulations where a midsize sedan (1700 kg) fitted with an adaptive cycle engine and a CVT is operated over three standard duty cycles: US06, UDDS, and HWFET, and compared with the results obtained from other engine cycles installed on the same vehicle. Four different engine cycles are compared: conventional 4-stroke, 6-stroke cycle with no air storage, 6-stroke cycle with air storage, and fully adaptive cycle with air storage and a number of strokes determined by instantaneous demand and state of charge of the storage tank. Results show that the fully adaptive engine achieves a better mileage in all scenarios, closely followed by the partially adaptive 6-stroke cycle with storage. Gains over a conventional 4-stroke powerplant range from 3.4 mpg on the HWFET cycle, to 7.6 mpg on the UDDS cycle. Furthermore, air storage allows the adaptive cycle engine to be considerably downsized while still being able to supply sufficient power even on the demanding US06 cycle, resulting in mileage figures over 70 mpg on the UDDS and HWFET cycles. The paper concludes with a discussion of control strategies that lead to high fuel economy while maintaining sufficient peak power, especially tailored to the fully and partially adaptive cycle engines.       ]]></description>
      <pubDate>Tue, 28 Jan 2020 09:42:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/1598321</guid>
    </item>
    <item>
      <title>New IIHS Ratings Show Pedestrian Crash Prevention is Gaining Ground</title>
      <link>https://trid.trb.org/View/1672719</link>
      <description><![CDATA[This article reports on a recent test conducted by the Insurance Institute for Highway Safety (IIHS) that evaluated the performance of pedestrian crash prevention systems in 16 midsize cars.  The author notes that annual pedestrian fatalities have been on the increase since reaching a low point in 2009.  Many automobile manufacturers are upgrading automatic emergency braking systems to include pedestrian recognition.  In the tests reported in this article, pedestrian crash prevention was standard on all six luxury cars and in six out of ten non-luxury cars.  The author briefly describes how the technology works to recognize pedestrians, then details each of the vehicles tested, focusing on those that received a superior rating as well as those that only received a basic rating or no credit.  To determine the ratings, points are added up based on the average speed reduction the vehicle achieves in five repeated test runs.  One chart illustrates the findings for the 16 automobiles tested.]]></description>
      <pubDate>Fri, 13 Dec 2019 17:05:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/1672719</guid>
    </item>
    <item>
      <title>Passenger Vehicle Occupant Fatality Rates By Type and Size of Vehicle (Updated)</title>
      <link>https://trid.trb.org/View/1596160</link>
      <description><![CDATA[This Research Note examines the fatality rate to occupants of passenger vehicles involved in fatal motor vehicle traffic crashes by passenger vehicle type and size of the vehicle. Data from 1997 to 2016 has been presented to show trends in occupant fatality rates. The rates are presented per 100,000 registered vehicles. As shown in Figure 1, the occupant fatality rates in all fatal crashes for passenger cars, SUVs, and pickup trucks are similar, but higher than the rates for vans in early years. After 2010, the rate differences between four passenger vehicle types are clearly shown. In 2016, the highest occupant fatality rates per 100,000 registered vehicles are passenger cars (9.94) followed by pickup trucks (8.92), SUVs (6.99), and vans (6.92).]]></description>
      <pubDate>Wed, 24 Apr 2019 09:30:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/1596160</guid>
    </item>
    <item>
      <title>7-XDCT: Compact and Cost-Efficient Dual Clutch Transmission for Small and Mid-Size Vehicles</title>
      <link>https://trid.trb.org/View/1433082</link>
      <description><![CDATA[The automotive industry continues to develop new powertrain technologies aimed at reducing overall vehicle level fuel consumption. The ongoing trends of “downsizing” and “down speeding” have led to the development of turbocharged engines with low displacement and high torque density. In order to meet the launch response requirements with these engines as well as fuel economy needs, transmissions with large ratio spreads will need to be developed. Due to the lack of torque amplification from the torque converter, the next generation of dual clutch transmissions (DCT) will need to have larger launch ratios and ratio spreads than currently available in production today. This paper discusses the development of a new family of DCT (called “xDCT”) for use in front wheel drive vehicles, aimed at meeting some of these challenges.         The xDCT family features two innovative concepts, the idea of “gear generation” and “supported shifts”. A combination of these features results in the development of a highly compact and efficient family of DCTs. The paper will begin with a definition of the xDCT concept followed by a layout of the gear sets for 7 and 10 speed versions of this transmission. Simulation results are used to show the powershift capability as well as efficiency of the developed transmission concept. Finally, a 3D design study is utilized to demonstrate key features of the transmission concept that will result in a highly efficient and compact transmission with low mechanical complexity and full powershift capabilities.       ]]></description>
      <pubDate>Mon, 23 Oct 2017 13:41:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/1433082</guid>
    </item>
    <item>
      <title>Assessment of Manual, Automatic and Continuously Variable Transmission Powertrains for Gasoline Engine Powered Midsize Saloon Vehicle</title>
      <link>https://trid.trb.org/View/1413449</link>
      <description><![CDATA[Modern integrated powertrains allow great scope for improvements in driveability, emissions and fuel consumption by optimizing the engine speed and load selection to deliver the demanded power. The aim of this study is to assess the exhaust emissions, road performance, road acceleration and fuel consumption of gasoline engine powered vehicle. The proposed emission index and fuel consumption rate are verified through chassis dynamometer tests using the urban part of European drive cycle (ECE-15). A midsize saloon vehicle equipped with an integrated gasoline engine with manual transmission (MT), automatic transmission (AT) and continuously variable transmission (CVT) powertrains. The results indicate that most of the carbon monoxide, carbon dioxide and unburned hydrocarbons emission, driveability and fuel consumption rate were improved for the CVT powertrains.]]></description>
      <pubDate>Thu, 28 Jul 2016 10:45:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/1413449</guid>
    </item>
    <item>
      <title>Light Vehicle Rear Visibility Assessment</title>
      <link>https://trid.trb.org/View/1376531</link>
      <description><![CDATA[This report describes a study in which the rear visibility characteristics of a set of 44 vehicles were measured. The visibility of a visual target consisting of a 29.4-inch-tall traffic cone (i.e., approximately the height of a 1-year-old child) was determined over a 6300-square-foot area stretching 35 feet to either side of the vehicle’s centerline and 90 feet back from the vehicle’s rear bumper. Rear visibility was measured for both a 50th percentile male driver (69.1 inches tall) and a 5th percentile female driver (59.8 inches tall). The areas over which the visual target was visually discernible using direct glances and indirect glances (i.e., using mirrors) was determined. Direct view (i.e., using glances out windows, not using mirrors) rear sight distances values taken in 1-foot increments across the back of vehicles were measured. The average of the eight distance values across the rear of the vehicle was then calculated. Direct-view rear sight distances were found to be shortest for small pickup trucks, compact SUVs, and compact passenger cars. Average rear sight distances were longest for a full-size van (45 feet), mid-size (44 feet) and large SUVs (≥ 34 feet), and large pickup trucks (35 feet). Rear, direct view blind zone areas for the vehicles measured were found to be smallest for small pickup trucks, compact passenger cars, and mid-size passenger cars. Direct view rear blind zone areas were largest for full-size vans, large and mid-size SUVs, large pickup trucks. Average blind zone sizes by vehicle types ranged from 100 square feet (small pickup trucks) to 1440 square feet (large SUVs).]]></description>
      <pubDate>Wed, 09 Dec 2015 11:06:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/1376531</guid>
    </item>
    <item>
      <title>Front and Side Car-To-Car CAE Based Crash Analysis of Different Class Vehicles</title>
      <link>https://trid.trb.org/View/1362105</link>
      <description><![CDATA[In recent years, the rapidly ncreasing market share of compact cars and SUVs has brought for both the consumer and the automaker the need to pay more attention to crash compatibility between the compact passenger vehicles and the light trucks (i.e., Pickups and SUVs). Vehicle compatibility regarding both self and partner protection in a frontal crash of different class vehicles is one of the hot issues in vehicle safety. Furthermore, it is expected that the amendment of UNECE-Regulation 94 to implement compatibility issues will happen in a couple years. This paper presents a front and side car-to-car Computer Aided Engineering (CAE) based crash of different class vehicles which describes a car accident in the real field. Structural engagement and energy balance of different class vehicles in front and side car-to-car crashes are identified. In this study, the conceptual design of compatibility compliant frontal vehicle structure which is designed to improve the distribution of frontal crash loading and structural engagement between vehicles is introduced. The effects of a proposed vehicle structure on possible candidates (i.e. Full Width Rigid Barrier (FWRB), Full Width Deformable Barrier (FWDB) and Progressive Deformable Barrier (PDB) for a compatibility evaluation test procedure and car-to-car crash are also investigated.]]></description>
      <pubDate>Thu, 30 Jul 2015 09:02:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/1362105</guid>
    </item>
    <item>
      <title>Research on the AE-MDB CAE Analysis for the Improved EURO NCAP Side Impact Test Procedure</title>
      <link>https://trid.trb.org/View/1361762</link>
      <description><![CDATA[According to the European New Car Assessment Program (EURO NCAP) side impact test procedures for 2015, the European Enhanced Vehicle Safety Committee (EEVC) Working Group 13 (WG13) has made a proposal for an improved side impact barrier: Advanced European Mobile Deformable Barrier (AE-MDB), which subjects test vehicles to more severe conditions compared to the current ECE R.95 MDB in many factors, including higher strength, increased weight and lengthened width. In this paper, development study of AE-MDB Finite Element (FE) model was performed preferentially in order to cope with the enhanced EURO NCAP side impact test procedures. In the second place, analysis and study for AE-MDB side impact were carried out to evaluate its crash severity for compact and midsize vehicles.]]></description>
      <pubDate>Tue, 21 Jul 2015 16:15:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/1361762</guid>
    </item>
    <item>
      <title>Repeatability of IIHS Small Overlap Frontal Crash Tests</title>
      <link>https://trid.trb.org/View/1359949</link>
      <description><![CDATA[This paper examines the repeatability of the Insurance Institute for Highway Safety’s small overlap frontal crash test, based on repeated tests of six midsize vehicle models. Vehicle accelerations, structural measures, restraint system performance, dummy kinematics, and dummy injury measures were compared. Vehicle longitudinal acceleration pulses were similar in repeated tests of the same vehicle. The test-to-test differences of the least repeatable vehicle structural intrusion measurement targets ranged from 4 to 8 cm, with the vehicle models having higher levels of structural intrusion showing the most variation. Restraint system deployments were not always repeatable because many vehicle restraint systems were not yet tuned for this crash mode. In vehicles where restraint systems performed consistently, similar dummy kinematics was observed. Head, neck, chest, leg, and foot injury measures were similar in repeated tests for these vehicles. In the vehicle where the restraint system did not perform consistently, different dummy kinematics was observed. This resulted in large variations in femur, knee, and tibia injury measures. None of these vehicles would have received different component or overall ratings whether the ratings were based on the results from the original or repeat test. The largest variations observed in this study were unimportant to the overall assessment of the vehicle, as measures from either test would promote the same design changes. Higher levels of variability likely reflect the fact that many of the vehicle structures and restraint systems were not specifically designed for this load case. Repeatability can be expected to improve as vehicles are redesigned to take the small overlap crash into account.]]></description>
      <pubDate>Mon, 06 Jul 2015 16:37:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/1359949</guid>
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