The US Transportation Collection consists of documents from across all transportation modes with specific focus on research reports from US DOT, state DOTs, and other transportation organizations.
Bookmark this collection: https://rosap.ntl.bts.gov/collection_ust or https://doi.org/10.21949/1530857.
Studies have shown that environmental factors affect driving behaviors. For instance, weather conditions and the presence of a passenger have been shown to significantly affect the speed of the driver. As one of the important measures of driving behavior is the gaze and head movements of the driver, such metrics can be potentially used towards unde
...
Tavakoli, A., Balali, V., & Heydarian, A. (2021). How do Environmental Factors Affect Drivers’ Gaze and Head Movements? (Report No. 21–23). Mineta Transportation Institute. https://doi.org/10.31979/mti.2021.2044
Tavakoli, Arash, Vahid Balali, and Arsalan Heydarian. How do Environmental Factors Affect Drivers’ Gaze and Head Movements?. Report no. 21–23. Mineta Transportation Institute, 2021. https://doi.org/10.31979/mti.2021.2044.
Tavakoli, Arash, et al. How do Environmental Factors Affect Drivers’ Gaze and Head Movements?. Mineta Transportation Institute, 2021, Report no. 21–23, ROSA P. https://doi.org/10.31979/mti.2021.2044.
Due to an increase in demand to shorten construction time as much as possible, the purpose of this project was to determine the optimum strength for concrete pavement before opening it to traffic and without jeopardizing long-term performance. Six test cells in MnDOT’s MnROAD project were constructed in 2017 with varying degrees of early loading. V
...
Khazanovich, L., Kosar, K., & Li, H. (2021). Evaluation of Long-Term Impacts of Early Opening of Concrete Pavements (Report No. NRRA202111). Minnesota. Department of Transportation. Office of Research & Innovation. https://rosap.ntl.bts.gov/view/dot/65468
Khazanovich, Lev, Katelyn Kosar, and Haoran Li. Evaluation of Long-Term Impacts of Early Opening of Concrete Pavements. Report no. NRRA202111. Minnesota. Department of Transportation. Office of Research & Innovation, 2021. https://rosap.ntl.bts.gov/view/dot/65468.
Khazanovich, Lev, et al. Evaluation of Long-Term Impacts of Early Opening of Concrete Pavements. Minnesota. Department of Transportation. Office of Research & Innovation, 2021, Report no. NRRA202111, ROSA P. https://rosap.ntl.bts.gov/view/dot/65468.
The Smart Energy Design Assistance Center assessed the administrative, technical, and economic aspects of feasibility related to the procurement and installation of photovoltaic solar systems on IDOT-owned buildings and lands. To address administrative feasibility, we explored three main ways in which IDOT could procure solar projects: power purcha
...
Rusk, T., Siegel, R., Larsen, L., Lindsey, T., & Deal, B. (2021). Technical and Financial Feasibility Study for Installation of Solar Panels at IDOT-Owned Facilities (Report No. FHWA-ICT-21-019). Illinois Center for Transportation. https://doi.org/10.36501/0197-9191/21-024
Rusk, Todd, Ryan Siegel, Linda Larsen, Tim Lindsey, and Brian Deal. Technical and Financial Feasibility Study for Installation of Solar Panels at IDOT-Owned Facilities. Report no. FHWA-ICT-21-019. Illinois Center for Transportation, 2021. https://doi.org/10.36501/0197-9191/21-024.
Rusk, Todd, et al. Technical and Financial Feasibility Study for Installation of Solar Panels at IDOT-Owned Facilities. Illinois Center for Transportation, 2021, Report no. FHWA-ICT-21-019, ROSA P. https://doi.org/10.36501/0197-9191/21-024.
This report presents findings of a research effort aimed at reviewing and updating existing Illinois Department of Transportation (IDOT) specifications and manuals regarding the use of geosynthetic materials in pavements. The project consisted of three tasks: evaluate current IDOT practice related to the use of geosynthetics; review research and st
...
Qamhia, I. I. A., & Tutumluer, E. (2021). Evaluation of Geosynthetics Use in Pavement Foundation Layers and Their Effects on Design Methods (Report No. FHWA-ICT-21-020). Illinois Center for Transportation. https://doi.org/10.36501/0197-9191/21-025
Qamhia, Issam I. A. and Erol Tutumluer. Evaluation of Geosynthetics Use in Pavement Foundation Layers and Their Effects on Design Methods. Report no. FHWA-ICT-21-020. Illinois Center for Transportation, 2021. https://doi.org/10.36501/0197-9191/21-025.
Qamhia, Issam I. A., and Erol Tutumluer Evaluation of Geosynthetics Use in Pavement Foundation Layers and Their Effects on Design Methods. Illinois Center for Transportation, 2021, Report no. FHWA-ICT-21-020, ROSA P. https://doi.org/10.36501/0197-9191/21-025.
The indirect tensile cracking test (referred to herein as “the IDT-CT”) was recommended for use in balanced mix design (BMD) specifications to address cracking susceptibility of dense-graded surface mixtures with A and D designations in Virginia. The test method for the IDT-CT, ASTM D8225-19, does not currently contain a precision statement for the
...
Habbouche, J., Boz, I., Diefenderfer, S. D., & Bilgic, Y. K. (2021). Round Robin Testing Program for the Indirect Tensile Cracking Test at Intermediate Temperature: Phase I (Report No. FHWA/VTRC 22-R3). Virginia Transportation Research Council (VTRC). https://rosap.ntl.bts.gov/view/dot/57511
Habbouche, Jhony, Ilker Boz, Stacey D Diefenderfer, and Yusuf K Bilgic. Round Robin Testing Program for the Indirect Tensile Cracking Test at Intermediate Temperature: Phase I. Report no. FHWA/VTRC 22-R3. Virginia Transportation Research Council (VTRC), 2021. https://rosap.ntl.bts.gov/view/dot/57511.
Habbouche, Jhony, et al. Round Robin Testing Program for the Indirect Tensile Cracking Test at Intermediate Temperature: Phase I. Virginia Transportation Research Council (VTRC), 2021, Report no. FHWA/VTRC 22-R3, ROSA P. https://rosap.ntl.bts.gov/view/dot/57511.
Distracted driving is a significant contributing factor to motor vehicle crashes. Cultural-based strategies seek to change the behaviors of individuals by connecting their social identity to nested layers of relationships. Relationships between family members or between supervisors and employees provide opportunities to reduce distracted driving. T
...
Otto, J., Finley, K., McMahill, A., & Arpin, J. (2021). Guidance to Promote Family Rules and Workplace Policies to Reduce Cell Phone Use While Driving and Promote Engaged Driving (Report No. FHWA/MT-21-008/8882-309-16). Montana. Department of Transportation. https://doi.org/10.21949/1518318
Otto, Jay, Kari Finley, Annmarie McMahill, and Jamie Arpin. Guidance to Promote Family Rules and Workplace Policies to Reduce Cell Phone Use While Driving and Promote Engaged Driving. Report no. FHWA/MT-21-008/8882-309-16. Montana. Department of Transportation, 2021. https://doi.org/10.21949/1518318.
Otto, Jay, et al. Guidance to Promote Family Rules and Workplace Policies to Reduce Cell Phone Use While Driving and Promote Engaged Driving. Montana. Department of Transportation, 2021, Report no. FHWA/MT-21-008/8882-309-16, ROSA P. https://doi.org/10.21949/1518318.
The deployment of autonomous vehicles (AVs) has been troubled by the soaring cost of operations and the public’s concerns about the safety and fairness issues potentially brought by the new mobility. As leading companies such as Waymo and Uber which have obtained permits to commercialize their robotaxi fleets domestically and overseas, it is urgent
...
Zhao, D., Huang, P., & Xu, M. (2021). Development of A Safe, Profitable, and Fair Robotaxi Deployment Strategy (Report No. #329). Mobility21, Carnegie Mellon University. https://rosap.ntl.bts.gov/view/dot/60108
Zhao, Ding, Peide Huang, and Mengdi Xu. Development of A Safe, Profitable, and Fair Robotaxi Deployment Strategy. Report no. #329. Mobility21, Carnegie Mellon University, 2021. https://rosap.ntl.bts.gov/view/dot/60108.
Zhao, Ding, et al. Development of A Safe, Profitable, and Fair Robotaxi Deployment Strategy. Mobility21, Carnegie Mellon University, 2021, Report no. #329, ROSA P. https://rosap.ntl.bts.gov/view/dot/60108.
The North Carolina Department of Transportation (NCDOT) modified the procedures for asphalt mixture design in 2018 in part, to increase the asphalt content and address observed cracking issues with asphalt mixtures. These changes have reduced the number of asphalt mixture types, changed compaction levels and the volumetric limits for some mixtures,
...
Underwood, B. S., Castorena, C., & Isied, M. (2021). Evaluation of New Asphalt Concrete Job Mix Formula Specifications (Report No. FHWA/NC/2020-12). North Carolina Department of Transportation. Research and Development Unit. https://rosap.ntl.bts.gov/view/dot/61447
Underwood, B. Shane, Cassandra Castorena, and Mayzan Isied. Evaluation of New Asphalt Concrete Job Mix Formula Specifications. Report no. FHWA/NC/2020-12. North Carolina Department of Transportation. Research and Development Unit, 2021. https://rosap.ntl.bts.gov/view/dot/61447.
Underwood, B. Shane, et al. Evaluation of New Asphalt Concrete Job Mix Formula Specifications. North Carolina Department of Transportation. Research and Development Unit, 2021, Report no. FHWA/NC/2020-12, ROSA P. https://rosap.ntl.bts.gov/view/dot/61447.
Highway work zones can be dangerous and unpredictable. Between 2003 and 2017, over 1,800 workers died on road construction sites. Eliminating injuries and deaths requires state transportation agencies to adopt robust safety cultures as there is a clear relationship between these cultures and worker behaviors. The Kentucky Transportation Cabinet (KY
...
Ammar, A., Al-shabbani, Z., Nassereddine, H., Van Dyke, C., & Dadi, G. B. (2021). Evaluating the Safety Cultures of KYTC Maintenance Crews (Report No. KTC-21-25/SPR20-582-1F). University of Kentucky Transportation Center. https://doi.org/10.13023/ktc.rr.2021.25
Ammar, Ashtarout, Zamaan Al-shabbani, Hala Nassereddine, Chris Van Dyke, and Gabriel B. Dadi. Evaluating the Safety Cultures of KYTC Maintenance Crews. Report no. KTC-21-25/SPR20-582-1F. University of Kentucky Transportation Center, 2021. https://doi.org/10.13023/ktc.rr.2021.25.
Ammar, Ashtarout, et al. Evaluating the Safety Cultures of KYTC Maintenance Crews. University of Kentucky Transportation Center, 2021, Report no. KTC-21-25/SPR20-582-1F, ROSA P. https://doi.org/10.13023/ktc.rr.2021.25.
As aggregate resources are depleted, there is a need to turn to more sustainable resources and alternatives to virgin aggregate for pavement preservation treatments. A recent NAPA survey (Williams et al., 2019) shows more RAP is stockpiled in Ohio than any other state, with a total of 11.2 million tons of RAP in 2018. Given the large quantities of
...
Robbins, M., Green, R., Buss, A., Durrani, A., Pinto, I., & Madson, K. (2021). Design of Microsurfacing and Chip Seal Mixes With RAP for Local Roadway Applications (Report No. FHWA/OH-2021/26). Ohio. Dept. of Transportation. Office of Research and Development. https://rosap.ntl.bts.gov/view/dot/58714
Robbins, Mary, Roger Green, Ashley Buss, Akmal Durrani, Irvin Pinto, and Katherine Madson. Design of Microsurfacing and Chip Seal Mixes With RAP for Local Roadway Applications. Report no. FHWA/OH-2021/26. Ohio. Dept. of Transportation. Office of Research and Development, 2021. https://rosap.ntl.bts.gov/view/dot/58714.
Robbins, Mary, et al. Design of Microsurfacing and Chip Seal Mixes With RAP for Local Roadway Applications. Ohio. Dept. of Transportation. Office of Research and Development, 2021, Report no. FHWA/OH-2021/26, ROSA P. https://rosap.ntl.bts.gov/view/dot/58714.
Public roads, streets, and sidewalks are managed by the City of Pittsburgh and those public space are used by all residents. The Department of Mobility and Infrastructure (DOMI) is responsible for issuing and enforcing permits for occupancy of the public right-of-way (ROW) in the City of Pittsburgh, such as for construction projects and utility lin
...
Qian, S., Ma, W., Choudhry, A., Cho, S., Jia, J., McHugh, J., Pathare, S., Rebovich, N., Rikhy, M., & Yuan, M. (2021). Smart Right-of-Way Permitting System for the City of Pittsburgh: Coordination, Pricing and Enforcement. Mobility21, Carnegie Mellon University. https://rosap.ntl.bts.gov/view/dot/60112
Qian, Sean, Wei Ma, Arnav Choudhry, Sarah Cho, Jerry Jia, Jimmy McHugh, Saurabh Pathare, Nik Rebovich, Mohit Rikhy, and Mingjia Yuan. Smart Right-of-Way Permitting System for the City of Pittsburgh: Coordination, Pricing and Enforcement. Mobility21, Carnegie Mellon University, 2021. https://rosap.ntl.bts.gov/view/dot/60112.
Qian, Sean, et al. Smart Right-of-Way Permitting System for the City of Pittsburgh: Coordination, Pricing and Enforcement. Mobility21, Carnegie Mellon University, 2021, ROSA P. https://rosap.ntl.bts.gov/view/dot/60112.
The COVID-19 pandemic dramatically affected transportation systems, including the ability of localities to pay for them. The authors explore the effects of the pandemic and the associated economic turbulence on local option sales taxes (LOSTs), an increasingly common revenue source for transportation in California and across the U.S. LOSTs have man
...
King, H., Amberg, N., Wasserman, J. L., Taylor, B. D., & Wachs, M. (2021). All Is Not LOST: Tracking California’s Local Option Sales Tax Revenues for Transportation During the Pandemic (Report No. UC-ITS-2021-18). University of California Institute of Transportation Studies. https://doi.org/10.17610/T6SW39
King, Hannah, Natalie Amberg, Jacob L. Wasserman, Brian D. Taylor, and Martin Wachs. All Is Not LOST: Tracking California’s Local Option Sales Tax Revenues for Transportation During the Pandemic. Report no. UC-ITS-2021-18. University of California Institute of Transportation Studies, 2021. https://doi.org/10.17610/T6SW39.
King, Hannah, et al. All Is Not LOST: Tracking California’s Local Option Sales Tax Revenues for Transportation During the Pandemic. University of California Institute of Transportation Studies, 2021, Report no. UC-ITS-2021-18, ROSA P. https://doi.org/10.17610/T6SW39.
The Indiana Department of Transportation (INDOT) manages and maintains over 28,000 miles of roadways. Maintenance of the roadways includes pavement repair in the summer and snow removal and de-icing in the winter. The prioritization of assets during winter storm events is crucial and impacts travel and safety. The objective of this project was to i
...
Mahlberg, J., Zhang, Y., Jha, S., Mathew, J. K., Li, H., Desai, J., Kim, W., McGuffey, J., Wells, T., Krogmeier, J. V., & Bullock, D. M. (2021). Development of an Intelligent Snowplow Truck that Integrates Telematics Technology, Roadway Sensors, and Connected Vehicle (Report No. FHWA/IN/JTRP-2021/27). Purdue University. Joint Transportation Research Program. https://doi.org/10.5703/1288284317355
Mahlberg, Justin, Yaguang Zhang, Sneha Jha, Jijo K Mathew, Howell Li, Jairaj Desai, and Woosung Kim, et al.. Development of an Intelligent Snowplow Truck that Integrates Telematics Technology, Roadway Sensors, and Connected Vehicle. Report no. FHWA/IN/JTRP-2021/27. Purdue University. Joint Transportation Research Program, 2021. https://doi.org/10.5703/1288284317355.
Mahlberg, Justin, et al. Development of an Intelligent Snowplow Truck that Integrates Telematics Technology, Roadway Sensors, and Connected Vehicle. Purdue University. Joint Transportation Research Program, 2021, Report no. FHWA/IN/JTRP-2021/27, ROSA P. https://doi.org/10.5703/1288284317355.
Super 2 corridors with passing lanes provide operational benefits to traditional two-lane highways by creating passing opportunities and reducing delay and crashes, leading to increased use of Super 2 corridors across Texas. However, as more passing lane length is added to a Super 2 corridor, the more it may resemble a traditional four-lane alignme
...
Brewer, M. A., Barrette, T. D., Florence, D., Glover, B., Fitzpatrick, K., & Venglar, S. P. (2021). Capacity and Cost Benefits of Super 2 Corridors (Report No. FHWA/TX-21/0-6997-R1). Texas A&M Transportation Institute. https://rosap.ntl.bts.gov/view/dot/60220
Brewer, Marcus A., Timothy D Barrette, David Florence, Brianne Glover, Kay Fitzpatrick, and Steven P. Venglar. Capacity and Cost Benefits of Super 2 Corridors. Report no. FHWA/TX-21/0-6997-R1. Texas A&M Transportation Institute, 2021. https://rosap.ntl.bts.gov/view/dot/60220.
Brewer, Marcus A., et al. Capacity and Cost Benefits of Super 2 Corridors. Texas A&M Transportation Institute, 2021, Report no. FHWA/TX-21/0-6997-R1, ROSA P. https://rosap.ntl.bts.gov/view/dot/60220.
Minnesota’s Office of Civil Rights at the Minnesota Department of Transportation administers the Disadvantaged Business Enterprise (DBE) program. The DBE program is intended to remedy past and current discrimination against disadvantaged business enterprises, ensure a level playing field and foster equal opportunity in DOT-assisted contracts, impro
...
Gaidzanwa, M., & Stewart, R. (2021). Impact of COVID-19 on Disadvantaged Business Enterprises in Minnesota (Report No. MN 2023-07). Minnesota. Department of Transportation. Office of Research & Innovation. https://rosap.ntl.bts.gov/view/dot/67838
Gaidzanwa, Moira and Rebecca Stewart. Impact of COVID-19 on Disadvantaged Business Enterprises in Minnesota. Report no. MN 2023-07. Minnesota. Department of Transportation. Office of Research & Innovation, 2021. https://rosap.ntl.bts.gov/view/dot/67838.
Gaidzanwa, Moira, and Rebecca Stewart Impact of COVID-19 on Disadvantaged Business Enterprises in Minnesota. Minnesota. Department of Transportation. Office of Research & Innovation, 2021, Report no. MN 2023-07, ROSA P. https://rosap.ntl.bts.gov/view/dot/67838.
The COVID-19 pandemic has drastically disrupted transit operations and induced significant transit ridership losses worldwide. Given its unprecedented duration, magnitude, and scale, the long-term effects are still unclear. Despite the differences, we can learn from previous disruptive events, such as terrorist attacks and epidemics, in the past 30
...
Liu, Y., Osorio, J. J., & Ouyang, Y. (2021). Literature Review and Data Analysis on the Impacts of Prolonged Events on Transit System Ridership (Report No. FHWA-ICT-21-021;ICT Series No. 21-026). Illinois Center for Transportation. https://doi.org/10.36501/0197-9191/21-026
Liu, Yining, Jesus J. Osorio, and Yanfeng Ouyang. Literature Review and Data Analysis on the Impacts of Prolonged Events on Transit System Ridership. Report no. FHWA-ICT-21-021;ICT Series No. 21-026. Illinois Center for Transportation, 2021. https://doi.org/10.36501/0197-9191/21-026.
Liu, Yining, et al. Literature Review and Data Analysis on the Impacts of Prolonged Events on Transit System Ridership. Illinois Center for Transportation, 2021, Report no. FHWA-ICT-21-021;ICT Series No. 21-026, ROSA P. https://doi.org/10.36501/0197-9191/21-026.
In an effort to manage increasing pollution and congestion in cities, regions, and megaregions around the world, governments have implemented various types of driving restriction programs. This report examines the effects of these restrictions and is divided into two chapters. The first provides a critical review of the literature on license-plate-
...
Guerra, E., & Reyes, A. (2021). Who Drives, Where, and When? An Evaluation of Behavioral Responses To License-Plated Based Driving Restrictions (Report No. CM2-52). University of Texas at Austin. Cooperative Mobility for Competitive Megaregions. https://rosap.ntl.bts.gov/view/dot/58949
Guerra, Erick and Ariadna Reyes. Who Drives, Where, and When? An Evaluation of Behavioral Responses To License-Plated Based Driving Restrictions. Report no. CM2-52. University of Texas at Austin. Cooperative Mobility for Competitive Megaregions, 2021. https://rosap.ntl.bts.gov/view/dot/58949.
Guerra, Erick, and Ariadna Reyes Who Drives, Where, and When? An Evaluation of Behavioral Responses To License-Plated Based Driving Restrictions. University of Texas at Austin. Cooperative Mobility for Competitive Megaregions, 2021, Report no. CM2-52, ROSA P. https://rosap.ntl.bts.gov/view/dot/58949.
Rapid transit systems are critical components of public transportation networks in urban areas, in terms of their impact on person mobility and on monetary, energy, and environmental costs associated with their operations. To facilitate effective planning for current and future needs, a framework is required that provides important consumption metr
...
Oke, J., Christofa, E., Gonzales, E., Han, Z., & Donaghy, S. (2021). Tracking the Energy and Emissions of MBTA Rapid Transit Vehicles (Report No. 21-023). Massachusetts. Dept. of Transportation. Office of Transportation Planning. https://rosap.ntl.bts.gov/view/dot/60026
Oke, Jimi, Eleni Christofa, Eric Gonzales, Zhuo Han, and Sean Donaghy. Tracking the Energy and Emissions of MBTA Rapid Transit Vehicles. Report no. 21-023. Massachusetts. Dept. of Transportation. Office of Transportation Planning, 2021. https://rosap.ntl.bts.gov/view/dot/60026.
Oke, Jimi, et al. Tracking the Energy and Emissions of MBTA Rapid Transit Vehicles. Massachusetts. Dept. of Transportation. Office of Transportation Planning, 2021, Report no. 21-023, ROSA P. https://rosap.ntl.bts.gov/view/dot/60026.
The Northeast Megaregion Travel Demand and Investment (NEMR TD&I) Model is a standard 4-step travel demand model that brings together population and job forecasts for 2030 and 2040 with detailed highway and public transportation network data across the 13-state Northeast Megaregion to help transportation planners evaluate the demand for new transpo
...
Landis, J. D. (2021). The Northeast Megaregion Travel Demand and Investment Model: Final Report and User’s Manual (Report No. CM236,37,50). University of Texas at Austin. Cooperative Mobility for Competitive Megaregions. https://rosap.ntl.bts.gov/view/dot/58662
Landis, John D. The Northeast Megaregion Travel Demand and Investment Model: Final Report and User’s Manual. Report no. CM236,37,50. University of Texas at Austin. Cooperative Mobility for Competitive Megaregions, 2021. https://rosap.ntl.bts.gov/view/dot/58662.
Landis, John D The Northeast Megaregion Travel Demand and Investment Model: Final Report and User’s Manual. University of Texas at Austin. Cooperative Mobility for Competitive Megaregions, 2021, Report no. CM236,37,50, ROSA P. https://rosap.ntl.bts.gov/view/dot/58662.
In today's competitive job market, local agencies need to grow their employee pipeline through various outreach strategies. This toolkit is intended to help broaden the reach and impact of job postings to ensure that local agencies are developing and marketing an exciting and desired career option. This toolkit includes sample job descriptions, tip
...
Stanley, K. (2021). Recruitment Toolkit for Local Transportation Agencies. Minnesota. Department of Transportation. Office of Research & Innovation. https://rosap.ntl.bts.gov/view/dot/77742
Stanley, Katherine. Recruitment Toolkit for Local Transportation Agencies. Minnesota. Department of Transportation. Office of Research & Innovation, 2021. https://rosap.ntl.bts.gov/view/dot/77742.
Stanley, Katherine Recruitment Toolkit for Local Transportation Agencies. Minnesota. Department of Transportation. Office of Research & Innovation, 2021, ROSA P. https://rosap.ntl.bts.gov/view/dot/77742.
Links with this icon indicate that you are leaving a Bureau of Transportation
Statistics (BTS)/National Transportation Library (NTL)
Web-based service.
Thank you for visiting.
You are about to access a non-government link outside of
the U.S. Department of Transportation's National
Transportation Library.
Please note: While links to Web sites outside of DOT are
offered for your convenience, when you exit DOT Web sites,
Federal privacy policy and Section 508 of the Rehabilitation
Act (accessibility requirements) no longer apply. In
addition, DOT does not attest to the accuracy, relevance,
timeliness or completeness of information provided by linked
sites. Linking to a Web site does not constitute an
endorsement by DOT of the sponsors of the site or the
products presented on the site. For more information, please
view DOT's Web site linking policy.
To get back to the page you were previously viewing, click
your Cancel button.