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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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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>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
    </image>
    <item>
      <title>Toxicity of two different size classes of tire particles from mixed end-of-life car tires to the springtail Sinella curviseta</title>
      <link>https://trid.trb.org/View/2604546</link>
      <description><![CDATA[Tire particles (TPs) are one of the biggest contributors to microplastic pollution, with reported soil concentrations exceeding 1 % close to busy roads. Little research has been done on the impact of TPs on soil organisms. In this study, two size classes of tire particles, 0-75 mcm and 75-180 mcm, were compared to determine if size does influence their toxicity to the springtail Sinella curviseta. Adult springtails were exposed for three weeks to TPs spiked in LUFA 2.2 natural soil at concentrations between 0.0016 % and 4 % (w/w). TP addition caused an increase of soil pH at the two highest concentrations, and a dose-related increase of soil Zn concentrations, which were higher for the larger TPs. Available (0.01 M CaCl2 extractable) Zn concentrations also increased, but were far below toxic levels in all cases. Springtail survival was not affected, but reproduction was decreased by 59 % and 39 % at the highest concentration (4 %) compared to the control for the 0-75 mcm and 75-180 mcm classes, respectively. EC50s were 3.50 % TPs in soil for the 0-75 mcm class and 6.36 % TPs for the 75-180 mcm class, and differed significantly between the two size classes (chi2df = 1 > 3.84, p < 0.05). These results suggest that smaller sized tire particles (0-75 mcm) are more toxic to S. curviseta than larger ones (75-180 mcm). It may also be concluded that long-term exposure to tire particles may threaten springtail populations at the highest concentrations currently found near roadsides.]]></description>
      <pubDate>Tue, 14 Oct 2025 09:08:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/2604546</guid>
    </item>
    <item>
      <title>Monitoring lead deposition around airports using bulk deposition samplers</title>
      <link>https://trid.trb.org/View/2548914</link>
      <description><![CDATA[Piston-engine aircraft that use leaded fuel represent the largest source of atmospheric lead in the United States. Lead levels are elevated in the atmosphere, soil, and in the blood of children that live close to and down-wind from airports. But statistical models examining the health effects of lead exposure near airports indicate that more refined and higher-resolution data are needed to better connect lead sources with human health effects. To address this, the authors tested the efficacy of bulk deposition samplers for quantifying the deposition of lead around Bellingham International Airport (BLI), an airport that is similar to approximately 1700 single-runway airports in the United States. The authors measured rates of lead deposition down-wind of BLI (4.8 μg Pb m−2d−1) that were twice as high as the average rate of lead deposition south and east of the airport and at a control site 6.7 km away from BLI (average rate, 2.3 μg Pb m−2d−1). The spatial pattern of lead deposition was consistent with prevailing winds and aircraft take-off trajectories during the sampling period. These data indicate that bulk-deposition samplers are useful for quantifying the rates and spatial distribution of lead deposition around airports. Their low cost, ease of deployment, and efficiency of sample collection indicate that bulk deposition samplers can generate the high-resolution data on lead deposition necessary for better assessing the transport direction of lead emissions from airports.]]></description>
      <pubDate>Fri, 16 May 2025 09:33:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2548914</guid>
    </item>
    <item>
      <title>Photochemical activity of water-soluble organic compounds in motor vehicle exhaust particulate matter</title>
      <link>https://trid.trb.org/View/2442157</link>
      <description><![CDATA[Particulate matter from motor vehicle exhaust is a type of important atmospheric particulates, which can absorb sunlight affecting its photochemical behavior. However, the photochemical activity of water-soluble organic compounds (WSOC) in motor vehicle exhaust particulate matter has not been explored. Here, the authors applied WSOC in particulate matter from motor vehicle exhaust to investigate the photogenerating ability of its reactive oxygen species (ROS) and its effect based on model phenol photodegradation with the comparison between WSOC in diesel particulate matter and in gasoline particulate matter. The WSOC in diesel particulate matter indicates higher ability to generate ROS. The main active substance produced by WSOC in the presence of light is 3WSOC*, the secondary substance is 1O2, and small amounts of OH and O2 are also produced. Less active material was produced as WSOC photoaging time increases. Furthermore, the WSOC in diesel particulate matter is more sensitive to light exposure compared to WSOC in gasoline particulate matter. The effects of common atmospheric ionic components on model phenol photodegradation were also explored. Whether WSOC of diesel particulate matter or WSOC of gasoline particulate matter, ammonium nitrate, ammonium sulfate, and ferric chloride promote degradation of model phenol, and copper sulfate inhibited model phenol degradation. However, a different trend emerged with the addition of sodium chloride, which promoted the degradation of model phenol in WSOC of diesel particulate matter and inhibited the degradation in WSOC of gasoline particulate matter.]]></description>
      <pubDate>Wed, 23 Oct 2024 11:46:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2442157</guid>
    </item>
    <item>
      <title>Toxicological evaluation of primary particulate matter emitted from combustion of aviation fuel</title>
      <link>https://trid.trb.org/View/2422940</link>
      <description><![CDATA[Recently, Sustainable Aviation Fuel (SAF) blends and novel combustion technologies have been introduced to reduce aircraft engine emissions. However, there is limited knowledge about the impact of combustion technology and fuel composition on toxicity of primary Particulate Matter (PM) emissions, comparable to regulated non-volatile PM (nvPM). In this study, primary PM was collected on filters using a standardized approach, from both a Rich-Quench-Lean (RQL) combustion rig and a bespoke liquid fueled Combustion Aerosol Standard (CAST) Generator burning 12 aviation fuels including conventional Jet-A, SAFs, and blends thereof. The fuels varied in aromatics (0-25.2%), sulphur (0-3000 ppm) and hydrogen (13.43-15.31%) contents. Toxicity of the collected primary PM was studied in vitro utilizing Air-Liquid Interface (ALI) exposure of lung epithelial cells (Calu-3) in monoculture and co-culture with macrophages (differentiated THP-1 cells). Cells were exposed to PM extracted from filters and nebulized from suspensions using a cloud-based ALI exposure system. Toxicity readout parameters were analyzed 24 h after exposure. Results showed presence of genotoxicity and changes in gene expression at dose levels which did not induce cytotoxicity. DNA damage was detected through Comet assay in cells exposed to CAST generated samples. Real-Time PCR performed to investigate the expression profile of genes involved in oxidative stress and DNA repair pathways showed different behaviors after exposure to the various PM samples. No differences were found in pro-inflammatory interleukin-8 secretion. This study indicates that primary PM toxicity is driven by wider factors than fuel composition, highlighting that further work is needed to substantiate the full toxicity of aircraft exhaust PM inclusive of secondary PM emanating from numerous engine technologies across the power range burning conventional Jet-A and SAF.]]></description>
      <pubDate>Mon, 16 Sep 2024 16:51:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2422940</guid>
    </item>
    <item>
      <title>Alteration of Hordeum vulgare and Sinapis alba germination and early growth in response to airborne low-metallic automotive brake wear debris</title>
      <link>https://trid.trb.org/View/2301567</link>
      <description><![CDATA[Road transportation significantly contributes to environmental pollution, both in terms of exhaust and non-exhaust (brake wear) emissions. As was proven, brake wear debris is released in a wide variety of sizes, shapes, and compositions. Although studies confirming the possible adverse health and environmental impact of brake wear debris were published, there is no standardized methodology for their toxicity testing, and most studies focus only on one type of brake pad and/or one test. The lack of methodology is also related to the very small amount of material released during the laboratory testing. For these reasons, this study deals with the mixture of airborne brake wear debris from several commonly used low-metallic brake pads collected following the dynamometer testing. The mixture was chosen for better simulation of the actual state in the environment and to collect a sufficient amount of particles for thorough characterization (SEM, XRPD, XRF, chromatography, and particle size distribution) and phytotoxicity testing. The particle size distribution measurement revealed a wide range of particle sizes from nanometers to hundreds of nanometers, elemental and phase analysis determined the standard elements and compounds used in the brake pad formulation. The Hordeum vulgare and Sinapis alba were chosen as representatives of monocotyledonous and dicotyledonous plants. The germination was not significantly affected by the suspension of brake wear debris; however, the root elongation was negatively influenced in both cases. Sinapis alba (IC50 = 23.13 g L-1) was more affected than Hordeum vulgare (IC50 was not found in the studied concentration range) the growth of which was even slightly stimulated in the lowest concentrations of brake wear debris. The plant biomass was also negatively affected in the case of Sinapis alba, where the IC50 values of wet and dry roots were determined to be 44.83 g L-1 and 86.86 g L-1, respectively.]]></description>
      <pubDate>Fri, 15 Dec 2023 13:55:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/2301567</guid>
    </item>
    <item>
      <title>Physical and chemical characteristics of particles emitted by a passenger vehicle at the tire-road contact</title>
      <link>https://trid.trb.org/View/2253908</link>
      <description><![CDATA[Non-exhaust emissions are now recognized as a significant source of atmospheric particulate matter and the trend towards a reduction of conventionally fueled internal combustion engine vehicles on the road is increasing their contribution to air pollution due to lower exhaust emissions. These particles include brake wear particles (BWP) and tire-road contact particles (TRCP), which are composed of tire wear particles (TWP), road wear particles (RWP) and resuspended road dust (RRD). The goal of this study has therefore been to design an original experimental approach to provide insight into the chemical composition of particles emitted at the tire-road contact, focusing on the micron (PM10-1mum) and submicron (PM1-0.1mum) fractions. Through this characterization, an examination of the different TRCP generated by different materials (tire, road surface, brake system) was conducted. To achieve this, TRCP were collected at the rear of the wheel of an instrumented vehicle during road and track tests, and a SEM-EDX analysis was performed. The experimental conditions have allowed us to demonstrate that, at the individual particle scale, TRCP are consistently associated with road dust materials and particles solely composed of tire or road materials are practically non-existent. The contribution of BWP to TRCP is marked by the emission of Fe-rich particles, including heavy metals like Ba, Mn and Cr. TWP, which result from rubber abrasion, consist of C-rich particles abundant in Si, Zn, and S. RWP, mainly composed of Al, Si, Fe, and Ca, can be either part of RRD or internally mixed with emitted TWP. The findings of this study highlight the substantial role of RRD to TRCP emissions under real driving conditions. Consequently, it underscores the importance of examining them simultaneously to achieve a more accurate estimation of on-road traffic emissions beyond the vehicle exhaust.]]></description>
      <pubDate>Thu, 05 Oct 2023 16:26:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2253908</guid>
    </item>
    <item>
      <title>Economic and environmental impact assessments of a newly designed energy system for marine applications</title>
      <link>https://trid.trb.org/View/2208720</link>
      <description><![CDATA[Marine transportation via the world's oceans is a critical way to convey goods and fuels between continents that cannot be performed cost-effectively by any other means. However, big ships heavily rely on fossil fuels, aggravating global carbon emissions. A key resolution to this dilemma is to employ clean fuels to reduce carbon emissions. This research paper introduces a new hybrid compound marine engine comprising a gas turbine, a solid oxide fuel cell, and a steam Rankine cycle. Three types of analyses, such as exergy, exergoeconomic, and exergoenvironmental analyses, are conducted on this proposed engine. It is found that the engine can produce a power of 15.5 MW, which is more than 48% compared to the traditional marine engine power, and the engine performance has up to 61% energy efficiency and 43% exergy efficiency. However, the exergetic efficiency of this engine based on fuel and product principal is 60%, which is more than 17% compared to its exergy efficiency. This engine has a 218 $/h Levelized cost rate and 139 mPt/h environmental rate. Finally, the average overall specific product exergy cost and environment are obtained to be 59 $/GJ and 20 mPt/MJ. By comparing five fuel blends, methane and hydrogen are the most economical and have the least impact on the environment; the second option is ethanol blend.]]></description>
      <pubDate>Fri, 21 Jul 2023 09:18:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2208720</guid>
    </item>
    <item>
      <title>Mobile measurement of vehicle emission factors in a roadway tunnel: A concentration gradient approach</title>
      <link>https://trid.trb.org/View/2166486</link>
      <description><![CDATA[Tunnels are the preferred experimental environments for estimating vehicle emission factors (EFs) under real-world driving conditions. In this study, online measurements of traffic-related air pollutants (including CO2, NOX, SO2, O3, particulate matter [PM], and volatile organic compounds [VOCs]) were conducted using a mobile laboratory in the Sujungsan Tunnel in Busan, Korea. Mobile measurements generated concentration profiles of the target exhaust emissions inside the tunnel. These data were used to produce a zonation of the tunnel, i.e., mixing and accumulation zones. There were differences between the CO2, SO2, and NOX profiles, and a starting point that was free from ambient air mixing effects could be set at 600 m from the tunnel entrance. The EFs of vehicle exhaust emissions were calculated using pollutant concentration gradients. The average EFs for CO2, NO, NO2, SO2, PM10, PM2.5, and VOCs were 149,000, 380, 55, 29.2, 9.64, 4.33, and 16.7 mg km-1.veh-1, respectively. Among the VOC groups, alkanes contributed more than 70% of the VOC EF. Mobile measurement-derived EFs were validated using the conventional EFs from stationary measurements. The EF results from the mobile measurements matched those from the stationary measurements, while the absolute concentration differences between them implied complex aerodynamic movements of the target pollutants inside the tunnel. This study demonstrated the usefulness and advantages of applying mobile measurements in a tunnel environment and indicated the potential of the approach for observation-based policymaking.]]></description>
      <pubDate>Fri, 26 May 2023 08:51:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/2166486</guid>
    </item>
    <item>
      <title>Air quality improvement through vehicle electrification in Hainan province, China</title>
      <link>https://trid.trb.org/View/2115000</link>
      <description><![CDATA[To improve the ecological environment, provinces in China have set ambitious goals for the electrification of fossil-fuel-powered vehicles (FVs) and the promotion of electric vehicles (EVs). Hainan is the first province to propose a clean energy target that schedules the banning of new FVs sales from 2030. Therefore, Hainan is a good case study to illustrate how this policy might improve regional air quality over the coming years. This study first developed an anthropogenic emission inventory of seven major air pollutants in 2017 in Hainan. The total emissions of CO, NOx, NH3, volatile organic compounds (VOCs), PM10 and PM2.5 and SO2 in 2017 were estimated as 247.56, 69.61, 61.87, 41.38, 37.02, 19.82, and 8.55 kt, respectively. Using the developed emission inventory, multiple scenarios of economic development were considered to assess the benefits to air quality from Hainan's goal of electrification. In comparison with 2017, the reductions in emissions of SO2, NOx, CO, PM10, PM2.5, VOCs, and NH3 by 2045 were projected to be 5.45 (11.11%), 275.07 (57.32%), 675.51 (34.07%), 8.39 (5.73%), 7.73 (8.24%), 81.15 (9.76%), and 4.89 (0.91%) kt, respectively, under the all-electric vehicle scenarios. These results indicate that this policy will not only reduce the emission of air pollutants but also avoid complex O3 pollution in the future. The findings of this work elucidate the effects of vehicle electrification policies on regional air quality and provide scientific support for policymakers in developing pollution control strategies..]]></description>
      <pubDate>Thu, 23 Feb 2023 09:17:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2115000</guid>
    </item>
    <item>
      <title>Biodiesel feedstock determines exhaust toxicity in 20% biodiesel: 80% mineral diesel blends</title>
      <link>https://trid.trb.org/View/2062963</link>
      <description><![CDATA[To address climate change concerns, and reduce the carbon footprint caused by fossil fuel use, it is likely that blend ratios of renewable biodiesel with commercial mineral diesel fuel will steadily increase, resulting in biodiesel use becoming more widespread. Exhaust toxicity of unblended biodiesels changes depending on feedstock type, however the effect of feedstock on blended fuels is less well known. The aim of this study was to assess the impact of biodiesel feedstock on exhaust toxicity of 20% blended biodiesel fuels (B20). Primary human airway epithelial cells were exposed to exhaust diluted 1/15 with air from an engine running on conventional ultra-low sulfur diesel (ULSD) or 20% blends of soy, canola, waste cooking oil (WCO), tallow, palm or cottonseed biodiesel in diesel. Physico-chemical exhaust properties were compared between fuels and the post-exposure effect of exhaust on cellular viability and media release was assessed 24 h later. Exhaust properties changed significantly between all fuels with cottonseed B20 being the most different to both ULSD and its respective unblended biodiesel. Exposure to palm B20 resulted in significantly decreased cellular viability (96.3 +/- 1.7%; p < 0.01) whereas exposure to soy B20 generated the greatest number of changes in mediator release (including IL-6, IL-8 and TNF-α, p < 0.05) when compared to air exposed controls, with palm B20 and tallow B20 closely following. In contrast, canola B20 and WCO B20 were the least toxic with only mediators G-CSF and TNF-α being significantly increased. Therefore, exposure to palm B20, soy B20 and tallow B20 were found to be the most toxic and exposure to canola B20 and WCO B20 the least. The top three most toxic and the bottom three least toxic B20 fuels are consistent with their unblended counterparts, suggesting that feedstock type greatly impacts exhaust toxicity, even when biodiesel only comprises 20% of the fuel.]]></description>
      <pubDate>Thu, 15 Dec 2022 14:15:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2062963</guid>
    </item>
    <item>
      <title>Insight into the penalty of exhaust emissions and fuel consumption by DPF regeneration of a diesel passenger car</title>
      <link>https://trid.trb.org/View/2056320</link>
      <description><![CDATA[In order to keep high fuel economy of diesel passenger cars, Diesel particulate filter (DPF) is periodically regenerated. In the regeneration process, extra fuel is injected into combustion chambers to achieve high exhaust temperature for the purpose of oxidizing particles accumulating on DPF substrate. It generates significant impacts on passenger car performance and exhaust emissions. In this paper, real-driving performance and exhaust emissions of a diesel car were tested over sixteen drivers under real-world conditions. DPF regeneration events were identified via exhaust temperature. Vehicle power output, fuel economy, and exhaust emissions in the trips both with and without DPF regeneration were analyzed. The results indicated that DPF regeneration events occurred in three of thirty-two test trips, and the maximum exhaust temperature was 250 degree Celcius during DPF regeneration. The DPF regeneration event led to the decrease of fuel economy and the increase of particle number, nitrogen oxides and carbon dioxides emission. Particle number emission factors were increased from approximately 109 #/km to 5 x 1010 #/km during DPF regeneration. The average power output of the car was in the range of 14.5 kW-15.6 kW and 15.8 kW-18.4 kW for the trips with and without DPF regeneration, respectively. However, Carbon monoxide emission factors were insensitive to DPF regeneration in the test trips.]]></description>
      <pubDate>Mon, 21 Nov 2022 16:19:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2056320</guid>
    </item>
    <item>
      <title>Effects of the continuous pulsation regeneration on the soot combustion in diesel particulate filter for heavy-duty truck</title>
      <link>https://trid.trb.org/View/2023857</link>
      <description><![CDATA[Continuous pulsation regeneration combustion of soot is employed for sine and cosine simulation study. Data showed that pressure uniformity of sine condition is better than that of cosine condition with the maximum pressure difference of 4353.5 Pa under the same simulation boundary conditions. The maximum regeneration temperature under cosine pressure is 46.12 K which is higher than that in sine form. Regeneration combustion reaction zone tends to be more stable laminar flow and Reynolds number of sine condition is 435.23 less than that of under cosine condition. The maximum Stanton number of cosine pressure condition is 3.67 and that of sine pressure condition is 5.15, which investigates heat transfer capacity of the sine pressure condition is better than that of the pressure of cosine form. The regeneration efficiency of inlet gradually increased from the minimum regeneration efficiency 74.18%-88.45% of sine and cosine. The soot under both pressure forms has achieved complete regeneration and the regeneration efficiency has exceeded 88% of porous medium filter body section. The soot regeneration combustion efficiency of the porous media filter section and outlet section is more sufficient under sine condition and the heat carried by the fluid can maintain the soot regeneration.]]></description>
      <pubDate>Wed, 12 Oct 2022 09:03:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/2023857</guid>
    </item>
    <item>
      <title>Exhaust and non-exhaust airborne particles from diesel and electric buses in Xi'an: A comparative analysis</title>
      <link>https://trid.trb.org/View/2023847</link>
      <description><![CDATA[Switching diesel buses (DBs) to electric buses (EBs) has been a global trend to reduce the use of fossil fuels and improve air quality. However, buses electrification may lead to additional vehicle weight, which may emit more non-exhaust particulate matter (PM) emissions. It remains debatable whether buses' electrification will successfully improve air quality as excepted. To assess the effect of the buses' electrification on the levels of PM emissions, PM emission factors (EFs) were evaluated from EBs and equivalent DBs. In addition, the total mass of PM emissions from EBs and equivalent DBs in 2021 was calculated in Xi'an using the real-world number and mileage of EBs. The non-exhaust PM EFs from EBs were larger than total exhaust and non-exhaust PM EFs from DBs, indicating that the electrification of buses would cause an increase in the level of PM emissions. The total annual mass of PM emissions from EBs was apparently higher than that from DBs. Moreover, a sensitivity analysis showed that tire wear, brake wear, and road wear PM emissions were more reliant on vehicle mileage, whereas resuspension of road dust was more dependent on vehicle weight. This finding can serve as a guideline for policymakers to design mitigation strategies for reducing extra PM emissions due to the electrification of buses by reasonably reducing vehicle weight and annual mileage.]]></description>
      <pubDate>Wed, 12 Oct 2022 09:03:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/2023847</guid>
    </item>
    <item>
      <title>Study on reducing carbon dioxide and harmful emissions of diesel-ignited natural gas engine</title>
      <link>https://trid.trb.org/View/2023845</link>
      <description><![CDATA[Natural gas (NG) is a clean and low-carbon fuel and the NG engine is one of the main measures used by the public transportation industry to achieve carbon peak targets. However, NG engines have problems, such as ignition difficulty and low thermal efficiency. The use of diesel to ignite NG is an effective solution to these problems; however, this solution will increase carbon dioxide (CO₂) emissions compared with NG engines. In this study, the potential of reducing CO₂ emissions from a diesel-pilot-ignited (DPI) NG engine by optimizing the injection parameters (injection pressure and injection timing) under different loads is studied through experiments. Furthermore, the formation mechanism of CO₂ in combination with chemical kinetics is analyzed. The results show that combustion in the DPI mode presents an obvious two-stage heat release and its CO₂ emission is 17.15% lower than that of pure diesel combustion (PDC). Under high-load conditions, as the diesel injection pressure increase, the THC and NOX emissions emissions decrease by 67.53% and 84.32%. As the diesel injection timing (DIT) advances, the NOX emissions increase from 1.84 to 22.96 g/kW.h respectively. According to the analysis of the chemical kinetic mechanism, the formation of CO₂ in DPI mode is primarily through the reaction of CO + O₂ = CO₂ + O, whereas in conventional diesel combustion (CDC) mode, CO₂ is formed through the reaction of CO + OH = CO₂ + H. Within the range of -18 to -5degreeCA ATDC DIT, increasing the diesel injection pressure (DIP) or advancing the DIT can improve the thermal efficiency of DPI NG engines and reduce CO₂ emissions.]]></description>
      <pubDate>Wed, 12 Oct 2022 09:03:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/2023845</guid>
    </item>
    <item>
      <title>Developing and analyzing eco-driving strategies for on-road emission reduction in urban transport systems - A VR-enabled digital-twin approach</title>
      <link>https://trid.trb.org/View/2001650</link>
      <description><![CDATA[A vast number of pollutants are generated from on-road commuting vehicles, and there is an increasing need to explore vehicle emission monitoring and mitigation strategies. Traditionally, vehicle emissions can be monitored and measured directly from on-vehicle devices such as a sensor at the tailpipe, or based on expensive data collection tools such as roadside units; while another mainstream research estimates vehicle emissions by relying on the connection to the vehicle motions, which can approximately calculate vehicle emissions under certain traffic conditions. This paper proposes a virtual reality (VR) enabled digital twin platform for on-road emission monitoring, and it develops and evaluates eco-driving strategies within a specific area. The proposed approach, integrating a VR-based digital environment, a micro-simulation model for background traffic, and a Motor Vehicle Emission Simulator for emission estimation, offers an alternative to collect and examine vehicle emissions such as NOx under various traffic conditions. A case study on a central business area in Melbourne is conducted and eco-driving strategies are tested in two scenarios. The first scenario concerns the impact of hybrid electric vehicles and connected autonomous vehicles, which points to the long-term benefit of having controllable and cleaner modes of transportation as a strategy. Results showed that manipulating the penetration rate of emission-friendly engines or motions could reduce vehicle emissions effectively. The second scenario concerns the real-time eco-routing based on emission-optimum, which points to the short-term benefit of emission control strategies. Human-in-the-loop experiments were conducted to test drivers' responses toward routing options. Results showed that over 90% of participants would follow the eco-routing recommendations completely. The presented study offers an alternative to data-generating, analyzing, and managing approaches for on-road emissions in urban transportation systems.]]></description>
      <pubDate>Wed, 10 Aug 2022 16:38:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2001650</guid>
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