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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>
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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>Exploring the Relationships Among Perceived Safety, Perceived Accessibility, and Travel Behavior</title>
      <link>https://trid.trb.org/View/2702636</link>
      <description><![CDATA[Accessibility, the potential to reach various opportunities that are spatially dispersed, is an important concept in transportation that has garnered an extensive amount of research. The methods of measurement of accessibility are numerous, and there has been no consensus on a singular best practice. Typical methods of measuring accessibility do not take into account individual differences. Perceived accessibility measures offer another approach to understanding individual differences inaccessibility. This project will contribute to perceived accessibility literature by conducting a study in the United States (U.S.) context in the state of California, as there have not been many studies conducted in the U.S. First, semi-structured interviews with adults residing in the Sacramento Area Council of Government (SACOG) region will be conducted. Next, a cross-sectional survey will be conducted using a sample of SACOG region residents. It is important to understand how perceptions of safety and accessibility may influence mode choice and ability to access economic opportunities.]]></description>
      <pubDate>Thu, 14 May 2026 16:47:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2702636</guid>
    </item>
    <item>
      <title>Equity Evaluation of Residents’ Transit+Walk Accessibility to Sacramento Healthcare Facilities</title>
      <link>https://trid.trb.org/View/2683211</link>
      <description><![CDATA[Access to healthcare is a key component of public health equity, yet many U.S. communities remain dependent on private vehicles for medical travel. This study introduces an integrated framework, the Transit+Walk Score (TWS), to evaluate how effectively residents of Sacramento, California, can reach healthcare facilities via public transit and how safely, comfortably, and conveniently they can walk from transit stops to those facilities. The research aims to inform planners, transit agencies, and policy makers in designing equitable and multimodal transportation systems. The research team combined geospatial network modeling and field-based walkability audits to assess 123 healthcare facilities across Sacramento, with 56 sites selected for detailed evaluation using the Pedestrian Environment Data Scan (PEDS) tool. The TWS integrated modeled transit travel times with on-the-ground walkability data to identify areas of high and low accessibility. Findings revealed that Downtown, Midtown, and East Sacramento exhibited the highest multimodal accessibility, while northern Arden-Arcade and outer suburban areas demonstrated the lowest. Educational attainment emerged as the strongest predictor of accessibility, highlighting structural inequities in pedestrian and transit infrastructure. The study concludes that equitable healthcare access requires both reliable transit and safe, continuous pedestrian networks. The TWS offers a scalable, data-driven tool to guide future investments that advance health equity, sustainable transportation, and inclusive community design.]]></description>
      <pubDate>Tue, 31 Mar 2026 10:12:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2683211</guid>
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    <item>
      <title>Exploring novel surrogate safety indicators measuring conflict riskiness and severity: A case study in Sacramento, United States</title>
      <link>https://trid.trb.org/View/2652420</link>
      <description><![CDATA[Determining appropriate traffic conflict indicators is essential for accurately conducting road safety evaluations. However, existing studies often fail to comprehensively address key factors such as the presence or absence of collision courses, the riskiness before and after the conflict point, and the mobility of the conflict point when selecting conflict riskiness indicators. Moreover, current conflict severity indicators are based on fully inelastic collision theory, which lacks sufficient modeling accuracy. This study delves into the characterization of collision and crossing courses in both angle and straight-line conflicts, providing a comprehensive analysis of the risks faced by road users both before reaching a conflict point and after one has passed it. Based on this analysis, a new combination scheme of conflict riskiness indicators is proposed. A two-dimensional, six-degrees-of-freedom potential collision model is then developed based on the theory of partially elastic collisions, and a new indicator, Extended Delta-E, is introduced. Finally, correlation analysis based on crash and conflict data is performed to compare the proposed indicators with traditional riskiness and severity indicators, evaluating their accuracy in road safety evaluation. The results demonstrate that the conflict rates and severity rates derived from the proposed indicators exhibit the strongest correlation with actual crash rates and crash severity rates, respectively, compared to other indicators. The conflict riskiness and severity indicators proposed in this study offer a more nuanced characterization of conflict events, and can serve as highly accurate alternative measures for crash-based road safety evaluations.]]></description>
      <pubDate>Fri, 06 Feb 2026 08:45:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/2652420</guid>
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    <item>
      <title>Incorporating Infrastructure and Vehicle Technology Requirements, Changes in Demand, and Decarbonization Policies’ Considerations into Freight Planning</title>
      <link>https://trid.trb.org/View/2592293</link>
      <description><![CDATA[This report develops an equitable and sustainable freight-oriented land use (LU) methodology to support future planning activities, enabling the integration of freight activity across urban, suburban, and rural areas and facilitating the transition of heavy- and medium-duty vehicles toward zero-emission. The methods include a literature review to identify freight sustainable strategies, policy analysis at different scales, characterization of local context, and demand/supply patterns. The latter examines the spatial distribution and land use characteristics of freight facilities and retail/service sectors in the Sacramento region to inform sustainable and equitable planning strategies. This analysis identifies co-location patterns, accessibility gaps, and sectoral interactions using a multi-dimensional approach integrating spatial clustering, distance analysis, population-employment dynamics, and environmental burdens. Data sources include Longitudinal Employer-Household Dynamics Origin-Destination Employment Statistics (LODES), American Community Survey (ACS), CalEnviroScreen, and OpenStreetMap, alongside geospatial tools in R. The findings suggest the need for targeted interventions to address potential conflicts, service deserts, and environmental justice concerns. The study proposes actionable strategies for planners to support balanced economic development and improve access to essential services.]]></description>
      <pubDate>Wed, 10 Sep 2025 09:22:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/2592293</guid>
    </item>
    <item>
      <title>What factors influence the adoption and use of dockless electric bike-share? A case study from the sacramento region</title>
      <link>https://trid.trb.org/View/2566091</link>
      <description><![CDATA[Now that dockless electric bike-share systems have become a fixture in major cities in the U.S., it is important to understand why someone chooses to use the service. Beyond socio-demographics, factors such as mode-related attitudes, the social environment, and the availability of the service may influence both its adoption and frequency of use. In this study, the authors modeled dockless electric bike-share adoption and use frequency using data collected from a household survey and a bike-share user survey from the Sacramento region. The authors used integrated choice and latent variable models to understand the influence of attitudes on electric bike-share adoption and use frequency. The authors developed three latent variables − bike affinity, car necessity, and bike social environment − using responses to eleven statements. The authors' models show that apart from socio-demographics, attitudes related to bike affinity and bike social environments significantly and positively influence bike-share adoption with a large effect size, whereas the car necessity attitude significantly and negatively influences the use frequency with a large effect size. Individuals with low incomes are less likely to adopt the bike-share service. The availability of electric bike-share in key locations (home and/or work and/or school) where an individual frequently goes significantly and positively influences adoption with a large effect size but does not influence use frequency. Findings from this study can inform the dockless electric bike-share policies of cities as well as the rebalancing strategies of service providers.]]></description>
      <pubDate>Thu, 21 Aug 2025 09:19:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2566091</guid>
    </item>
    <item>
      <title>Evaluation of Long-Term Performance of Transportation Earthworks Prone to Weather-Driven Deterioration Under Changing Climate</title>
      <link>https://trid.trb.org/View/2548808</link>
      <description><![CDATA[Embankments are key transportation infrastructure features providing essential support for long, linear stretches of transportation infrastructure, including highways and railways, in California and globally. Clay embankments are susceptible to weather-related deterioration processes that can gradually compromise their stability and, in some cases, lead to unexpected failures. Climate change, along with the associated shifts in weather patterns, is projected to adversely impact weather-related deterioration processes, leading to exacerbated failures and/or shorter service life. This study evaluated the impact of climate change on the rate of weather-driven deterioration of embankments in two locations in California: Los Angeles and Sacramento. Specifically, a multi-phase hydromechanical geotechnical model was developed for an exemplar clay embankment. The model is capable of simulating long-term performance of an embankment subject to a climate-controlled flux boundary. The model was used to perform numerical simulations where temperature and rainfall levels were adjusted to reflect four possible future climate change scenarios: Case (1) no average temperature or average precipitation changes; Case (2) +3℃ average temperature change and –12.5% average precipitation change; Case (3) +3℃ average temperature change and no average precipitation change; and Case (4) +3℃ average temperature change and +12.5% average precipitation change. Performance indicators were obtained from the numerical simulations to compare the effect of climate change in Los Angeles and Sacramento. It was concluded that climate change is generally projected to adversely affect the long-term performance of clay embankments, which can put critical transportation infrastructure and the communities that depend on it at risk.]]></description>
      <pubDate>Tue, 27 May 2025 09:30:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2548808</guid>
    </item>
    <item>
      <title>Can bike-share change attitudes? Evidence from the Sacramento, California region</title>
      <link>https://trid.trb.org/View/2533958</link>
      <description><![CDATA[Many existing studies of bike-share services focus on system dynamics and user characteristics, but less is known about how bike-share influences bicycling more broadly. In this study, the authors examine how a bike-share system influenced travel attitudes of residents through a repeated cross-sectional survey conducted before and after the opening of the system. The study focused on one of the largest dock-less electric-assisted bike-share systems in the US in 2018, the Jump system in three California cities: Sacramento, West Sacramento, and Davis. Results suggest that the bike-share system is likely to have been responsible, at least in part, for more favorable attitudes toward bicycling and less favorable attitudes toward driving. This research demonstrates that the benefits of bike-share can go beyond the general use of the system. Bike-share can also be seen as an intervention that has widespread psychological effects that may increase the likelihood of bicycling.]]></description>
      <pubDate>Wed, 30 Apr 2025 16:59:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2533958</guid>
    </item>
    <item>
      <title>Sensitivity Testing of Induced Highway Travel in the Sacramento Regional Travel Demand Model</title>
      <link>https://trid.trb.org/View/2516342</link>
      <description><![CDATA[Since the 1970s, stakeholders have expressed concerns about the ability of transportation travel demand used by metropolitan planning organizations to represent induced travel from expanded highway capacity. Failure to adequately represent induced travel will underestimate vehicle miles traveled and congestion when comparing scenarios with and without highway capacity expansion. To examine the magnitude of potential biases, the authors use the state-of-the-practice transportation demand model, the Sacramento Council of Governments (SACOG) SACSIM19 model, to examine (1) the model's representation of induced travel, (2) the influence of variation in key inputs on vehicle travel and roadway congestions, and (3) the effect of changes in induced travel-related input variables on the comparisons of scenarios with and without highway expansions.]]></description>
      <pubDate>Mon, 03 Mar 2025 17:01:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2516342</guid>
    </item>
    <item>
      <title>Evaluation of a Novel Methodology to Measure Bicycle Network Connectivity</title>
      <link>https://trid.trb.org/View/2465003</link>
      <description><![CDATA[Bicycling is among the most environmentally sustainable and economically affordable travel modes available. The popularity of bicycling activities strongly depends on the availability of well-connected bicycle networks. Existing methodologies to measure network connectivity are often purely academic, complex, subjective, or locally specific. This study aims to develop and test a reliable methodology for evaluating bicycle network connectivity. The study proposed two weighted shortest-path graph algorithms: the low-stress bike network connectivity (LSBNC), and designated bicycle network connectivity (BNC) algorithms. The weights of the algorithms were the function of slope, level of traffic stress, and link length. The authors tested the algorithms on the California cities of San Francisco, Davis, Sacramento, and Hayward, along with San Francisco Bay Area counties, and found that algorithms can produce meaningful quantitative connectivity scores. The results indicate that Davis’s BNC and LSBNC scores are 0.36 and 0.40, whereas for San Francisco, these scores are 0.07 and 0.47, respectively. The remaining Bay Area county’s networks are better connected through a low-stress bike network compared with a designated bicycle network. Finally, the authors fitted the connectivity scores with the designated bike network or low-stress bike network intersection density and found that the BNC score can be calculated with goodness of fit (R²) of 0.90 and LSBNC can be calculated with R² of 0.38. The developed methodology will help planners, engineers, and policymakers with the ability to efficiently evaluate bicycle network connectivity.]]></description>
      <pubDate>Fri, 24 Jan 2025 11:13:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2465003</guid>
    </item>
    <item>
      <title>Sensor placement considering the observability of traffic dynamics: On the algebraic and graphical perspectives</title>
      <link>https://trid.trb.org/View/2450665</link>
      <description><![CDATA[In this paper, the authors present a new sensor location model that aims to maximize observability of link densities in a dynamic traffic network described using a piecewise linear system of ordinary differential equations. The authors develop an algebraic approach based on the eigenstructure to determine the sensor location for achieving full observability with a minimal number of sensors. Additionally, a graphical approach based on the concept of structural observability is developed. By exploiting the special property of flow conservation in traffic networks, the authors derive a simple analytical result that can be used to identify observable components in a partially observable system, which is the main contribution of this paper. The graphical and algebraic properties of observability are then integrated into a sensor location optimization model considering a wide range of traffic conditions. Through numerical experiments, the authors demonstrate the good performance of their sensor deployment strategies in terms of the average observability and estimation errors.]]></description>
      <pubDate>Wed, 20 Nov 2024 12:00:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/2450665</guid>
    </item>
    <item>
      <title>Dataset of Underserved Microtransit Users in the Sacramento Area, California [supporting dataset]</title>
      <link>https://trid.trb.org/View/2447266</link>
      <description><![CDATA[Transportation-disadvantaged populations often face significant challenges in meeting their basic travel needs. Microtransit, a technology-enabled transit mobility solution, can potentially address these issues by providing on-demand, affordable, and flexible services. However, the extent to which microtransit serves underserved populations and the factors influencing their adoption remain unclear. This research focuses on SmaRT Ride, a microtransit pilot program operated by the Sacramento Regional Transit (SacRT) in the Sacramento area. From early February to the end of May 2024, online and intercept surveys were conducted among underserved populations to understand their travel behavior. After data cleaning, 180 valid responses were collected. Descriptive analysis of the data shows that SmaRT Ride has significantly improved transportation access for these communities. Furthermore, logistic regressions were employed to explore factors influencing the willingness to adopt microtransit and differences cross microtransit users versus non-users with microtransit awareness. Results show that perceived usefulness, the extent to which an individual lacks transportation options, families with children under 18 benefiting from free transit services, and familiarity with ride-sharing services correlate positively to high intention to adopt microtransit; whereas the perceived high mental effort of using it works as a barrier and frequent light rail users are less inclined to adopt microtransit. For underserved individuals who are aware of microtransit, their homeownership, employment status, frequency of using public transit services, and attitude towards transit significantly affect actual microtransit use. This study contributes to the literature by examining a broad range of factors influencing microtransit use and adoption among underserved populations through original survey data. However, it is limited by its cross-sectional design and small dataset.]]></description>
      <pubDate>Wed, 20 Nov 2024 10:20:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/2447266</guid>
    </item>
    <item>
      <title>Exploring Microtransit Adoption and Its Impacts on Transportation Access for Underserved Populations</title>
      <link>https://trid.trb.org/View/2447265</link>
      <description><![CDATA[Transportation-disadvantaged populations often face significant challenges in meeting their basic travel needs. Microtransit, a technology-enabled transit mobility solution, has the potential to address these issues by providing on-demand, affordable, and flexible services with multi-passenger vehicles. The ways in which microtransit supports underserved populations and the factors influencing its adoption are not well-studied, however. This research examines SmaRT Ride, a microtransit pilot program in the Sacramento, California, area operated by Sacramento Regional Transit. The project evaluates a broad range of factors influencing microtransit adoption and travel behavior among underserved populations using original revealed choice survey data collected from February – May 2024 with online and intercept surveys. A descriptive analysis revealed that SmaRT Ride has improved transportation access for these communities, complements the transit system by connecting fixed-route transit, and offers a cost-effective alternative to other transportation modes. A binary logistic regression was employed to explore differences between microtransit users and non-users with microtransit awareness. The results indicate that homeownership, employment status, frequency of public transit service use, and attitude towards transit significantly affect microtransit use. Homeowners are more likely to use microtransit, while households without employed members are less likely. In contrast, part-time employees show a higher inclination to use microtransit. Regular public transit users are also more likely to incorporate microtransit into their routines, with a positive attitude toward public transit further increasing the likelihood of its use. The nuanced understanding of microtransit adoption presented here can inform targeted strategies to promote its use among transportation-disadvantaged groups. The results suggest that integrating microtransit with existing transit, outreach programs, discounted or free access, extended service hours, and supporting homeownership and affordable housing in transit-rich areas can encourage microtransit adoption by low-income and/or underserved individuals.]]></description>
      <pubDate>Wed, 20 Nov 2024 10:20:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/2447265</guid>
    </item>
    <item>
      <title>Measuring, Analyzing and Identifying Small-Area VMT Reduction</title>
      <link>https://trid.trb.org/View/2446968</link>
      <description><![CDATA[Senate Bill 375, signed into law in 2008, directed the California Air Resources Board to collaborate with the state’s metropolitan planning organizations (MPOs) to set regional targets for reductions in GHG emissions from passenger vehicles. The MPOs are required to adopt Sustainable Communities Strategies (SCSs) that lay out the strategies by which the region will achieve its GHG reduction target, including strategies to reduce vehicle miles traveled (VMT). Strategies to reduce VMT include changes to the built environment, to both land development patterns and the transportation system, that reduce the need for driving. The goal of this project was to document on-the-ground changes in the built environment in selected communities over a two-decade period and assess whether changes in VMT have occurred over the same period. A secondary aim was to explore the contribution of local and/or regional policy change and public investments such as transit, bike, and pedestrian infrastructure as well as private development investments to the observed on-the-ground changes to the built environment. This project comprised case studies of Sacramento, Fresno, and Santa Monica, communities that experienced notable changes in their transportation systems and land development patterns between 2000 and 2019. The first part of the case-study analysis focused on identifying changes to the built environment in the area and the factors contributing to those changes, including public policies (broadly defined) and market forces. The second part of the case-study analysis examined changes in travel patterns in the area over this period of time using available data sources. Estimates of VMT showed reductions over time, while estimates of the shares of trips by active transportation modes increased, though the small sample sizes on which estimates were based makes them highly uncertain. In these case studies changes to the built environment were associated with changes in travel behavior consistent with the goal of reducing VMT. To more robustly evaluate the impact of built environment changes on VMT in specific areas, better data on travel patterns must be collected before and after the changes occur.]]></description>
      <pubDate>Thu, 14 Nov 2024 09:48:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/2446968</guid>
    </item>
    <item>
      <title>Hydraulic Performance Simulation of Fully Permeable Highway Shoulder</title>
      <link>https://trid.trb.org/View/2281196</link>
      <description><![CDATA[This paper presents the results of simulations to assess the hydraulic performance of a fully permeable shoulder for conventional highway stormwater runoff management. The simulations were performed using HYDRUS software and specific input modeling parameters that were measured in the lab. The hydraulic performance was evaluated by determining the minimum required critical aggregate depth to capture 24 hr rainfall based on 2, 50 and 100-yr recurrence period in Sacramento area. This result was verified with annual simulation by determining the number of overflow that could occur under 2, 50 and 100 yr recurrence storm events. Additional simulations were performed to determine the impact of drawdown and assessing the effect of clogging of open graded surface pavement. Results showed that an aggregate depth of about 1 m was adequate for retaining the runoff from two lane highways. Annual simulations indicate the overflow is directly related to severe storm events and subgrade soil saturated conductivity. Clogging simulation showed that overflow will only occur when the permeability of surface pavement reduces by 90% and that means only 10% or less of void space is open.]]></description>
      <pubDate>Tue, 05 Nov 2024 09:06:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2281196</guid>
    </item>
    <item>
      <title>Assessing grocery shopping behaviors during a health crisis</title>
      <link>https://trid.trb.org/View/2385063</link>
      <description><![CDATA[Though pandemics are relatively rare, epidemics, health crises, and other disasters are not. This study analyzes how people accessed essential goods, specifically groceries, during the early stages of the COVID-19 pandemic, which is likely representative of how consumers will behave during comparable crises. Specifically, the study explores shopping channels and transportation implications related to public health measures and various population characteristics in the United States and California. The analyses evidenced geographic differences, which the study explores in the Sacramento Area Council of Governments region. This research uses data from several time-varying sources to perform (1) aggregate or population-level (using local projections methodology) and (2) disaggregate or individual-level (using multinomial logit, MNL, models) analyses. The MNL models explore personal attributes related to shopping channel choices using the COVID-19 Future Survey (Salon et al., 2021). The disaggregate analysis explores basket size, trip and order/delivery frequencies, and complementary or substitution shopping patterns collected from the study region (Forscher et al., 2021). COVID-19 led to increased adoption of online grocery shopping, though most people still visited the store. Aggregate patterns show that grocery store visits quickly returned to the pre-COVID-19 baseline, with influences from increased COVID-19 cases and mask mandates. Even more, the authors model the revealed preferences of survey participants and identify groups that may have experienced additional barriers or benefits to adopting a shopping channel. This study identifies income, ability status, and age as significant considerations for equitable access to essential goods during a crisis. The findings of this study can inform planning and policy efforts to minimize harm in future crises.]]></description>
      <pubDate>Mon, 24 Jun 2024 09:24:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/2385063</guid>
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