National Academies Press: OpenBook

Roundabout Practices (2016)

Chapter: Appendix C - Questionnaire Responses

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Suggested Citation:"Appendix C - Questionnaire Responses." National Academies of Sciences, Engineering, and Medicine. 2016. Roundabout Practices. Washington, DC: The National Academies Press. doi: 10.17226/23477.
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59 APPENDIX C Questionnaire Responses

Mini-Roundabouts Single-Lane Roundabouts Multilane Roundabouts Mini-Roundabouts Single-Lane Roundabouts Multilane Roundabouts Alaska 2001 3 20 9 0 11 7 Arkansas 2008 0 25 4000 California 1993 No answer 253 44 0 11 12 Connecticut 2007 2 20 1302 Delaware 2004 1 11 1 1 11 1 Florida 1996 4 13 11 0 11 3 Georgia 1999 3 130 2 2 20 0 Idaho A No answer No answer No answer No answer No answer No answer Illinois 2006 No answer No answer No answer No answer No answer No answer Indiana 2008 0 122 39 0 5 9 Iowa 2006 10 37 0709 Kansas 2000 No answer 77 34 0 13 7 Kentucky 2002 0 10 1 No answer 9 Louisiana 2002 No answer No answer No answer 0 22 1 Maine 2001 No answer 19 5 No answer 19 5 Maryland 1992 10 114 37 1 53 24 Massachusetts 2010 No answer No answer No answer 0 4 2 Michigan 2005 1 50 30 0 10 15 Minnesota 2002 2 107 32 0 24 9 Mississippi 2001 30 20 3306 Missouri 2000 5 200 20 1 55 15 Montana 2007 1 20 12 0 10 10 Nebraska 2005 No answer 6 4 No answer 6 2 Nevada 2010 No answer 10 4 No answer 4 No answer New Hampshire 2007 0 28 1806 New Mexico 2000 No answer 15 15 No answer 10 10 New York 2000 2 100 25 0 65 25 North Carolina 1999 0 229 18 0 120 16 North Dakota 2012 10 2 No answer No answer 1 No answer Oregon 1999 0 60 10 0 1 1 Pennsylvania 2005 0 20 1 0 17 1 Rhode Island 2003 No answer 3 3 No answer No answer No answer South Dakota B No answer 00003 Texas 1996 No answer No answer No answer No answer No answer No answer Vermont 1993 1 12 1601 Virginia 2002 No answer 145 15 No answer 110 5 Washington 1997 9 210 85 4 80 30 West Virginia 2010 400450 Wisconsin 1999 0 154 175 0 100 147 Wyoming 2010 No answer No answer No answer 0 5 0 A: Our agency has not built a roundabout B: Our agency has planned or designed a roundabout, but not yet built a roundabout State Approximately what year did your state agency build its first roundabout? By roundabout category, approximately how many roundabouts have been opened within your state. By roundabout category, approximately how many roundabouts have been opened by your state agency (roundabouts that your state has jurisdiction over and/or were built as part of projects overseen by your state agency)?

Alaska Arkansas California Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Mexico New York North Carolina North Dakota Oregon Pennsylvania Rhode Island South Dakota Texas Vermont Virginia Washington West Virginia Wisconsin Wyoming State Urban Suburban Rural Urban Suburban Rural Urban Suburban Rural All None None Most Some Some Some Some None Yes Most Some Some All None None Yes None None None Some Most Some Some Most None Yes All None None Some Most Some None All None Yes All None None Some Some Most All None None Yes Some Most None Most Most All Most Most All Yes Most Some Some Some Some Some Some Yes None None None Some Most Some Some Most Some No Some Most None Some Most Some Some Most None Yes Most Some Some Most Some None Yes None None None Some Most Some None All None No None None None Some Most Some None None All Yes None None None Some Most Some Most Some Yes Most Some None Some Most Most Some Most Some Yes None None None Some Some None Some Some None No None Most Some Some Some Some Most Some Some Yes Most Most None Most Some Some Most Some Some Yes Some Most Most Some All No Most None Some Most Some Some Most Some None No All None None Some Most Some All None None Yes All None None Some Some Some Some Some None No None None None Some Some Some None None None No None None None Some Most Some Some Some None Yes Most Some None Most Some None All No None All None Some Most Some Some Most Some Yes None None None Some Most Some Some Most None Yes Some Some Some Most None None None No None None None Some Most Some None All None No None None None Some Some Most None None All No All None None All None None None All None Yes None None None All None None None None None No No All None None Some Some Some All None None No Some Most Some Some Most Some Yes Some Some Some Most Some Some Some Most Some Yes Most Some None Most Some None No None None None Some Some Most Some Most Some Yes None None None Some Some Some None None None Yes By roundabout category, approximately what proportion of mini- roundabouts are in urban, suburban and rural areas of your state? lane roundabouts are in urban, suburban and rural areas of your state? By roundabout category, approximately what proportion of multilane roundabouts are in urban, suburban and rural areas of your state? Do you maintain a database listing roundabouts in your state? By roundabout category, approximately what proportion of single

Alaska Arkansas California Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Mexico New York North Carolina North Dakota Oregon Pennsylvania Rhode Island South Dakota Texas Vermont Virginia Washington West Virginia Wisconsin Wyoming State Improved safety performance Shorter vehicular delays Higher capacity Lower initial capital costs Lower life-cycle costs Aesthetic/urban design improvements Responding to request from local jurisdiction Responding to request from elected official Lower speeds/traffic calming Other Other Note Usually Usually About half the time About half the time Usually Usually Seldom Seldom Seldom No Seldom About half the time About half the time Never About half the time About half the time Usually About half the time Seldom No About half the time Usually About half the time Seldom Never About half the time Seldom Never Seldom Yes Always About half the time Seldom Seldom About half the time About half the time About half the time About half the time Usually Yes About half the time About half the time About half the time Never Never About half the time Never Never About half the time A Don't know Usually About half the time Seldom About half the time Seldom About half the time About half the time Seldom About half the time Always B No Usually About half the time About half the time About half the time About half the time About half the time Usually About half the time About half the time Yes Usually About half the time About half the time Seldom About half the time Seldom Seldom Seldom Seldom Don't know Usually About half the time About half the time Seldom Seldom Seldom Never Never About half the time Yes Always Usually Usually Always Always About half the time Always Always Always Always C Yes Usually About half the time Usually About half the time About half the time About half the time About half the time About half the time Usually Yes Usually Usually Usually Seldom About half the time Seldom Usually Usually Usually Yes Usually Usually Usually Seldom Seldom Seldom Usually Seldom Usually Yes Usually Usually Usually Never About half the time About half the time Seldom Seldom Never Yes Always Usually Usually Usually Usually Seldom About half the time Seldom Usually Don't know Usually Usually Usually About half the time About half the time About half the time About half the time Seldom Seldom Yes Usually Usually Usually Seldom About half the time About half the time Seldom Seldom Usually Yes About half the time Usually About half the time Seldom About half the time Seldom Never About half the time No Usually Seldom About half the time Seldom About half the time About half the time About half the time About half the time Seldom Yes Always Usually Usually Seldom Usually About half the time About half the time Seldom Seldom Yes Usually Seldom Seldom Seldom Seldom Seldom Seldom Seldom Seldom Yes Usually Seldom Seldom Never Seldom Never Never Never About half the time Don't know Usually Usually Usually Seldom About half the time About half the time About half the time Seldom Usually Yes Usually Usually Usually Seldom Seldom Seldom Usually Usually Usually Don't know Usually Usually Usually Seldom Usually Usually Seldom Seldom Usually About half the time D Yes Always Usually Seldom Seldom About half the time Seldom About half the time Seldom Seldom Seldom E Yes Always Usually Usually Seldom Seldom Seldom About half the time Never Usually Don't know Usually Usually Usually Seldom Usually Usually Usually Usually Usually Yes Usually About half the time About half the time Never Seldom Never Seldom Seldom Seldom Yes Always Always Always Seldom Seldom About half the time About half the time Seldom About half the time No Always Always About half the time Never Always Never Seldom Seldom About half the time F No G Don't know Always Usually Seldom Seldom Seldom Never Never Never Usually Never Yes Always Always Always Always Always Always Always Always Always Yes Usually Usually Usually Usually Usually Usually Usually H Yes Usually Usually Usually Never About half the time Seldom Seldom Seldom No Usually Usually Usually Seldom Seldom Seldom Seldom Seldom Seldom Yes Usually Usually Seldom Never Never Never Never Never Never No Please select the frequency in which your state agency selects roundabouts based on the following set of common reasons for selecting roundabouts. A: Lower off-peak delays than a traffic signal B: FDOT directive to consider roundabouts when doing a project C: Our primary goal is improved safety. D: Quite a few of our roundabouts come to be once a project has been started for a safety or capacity concern - we typically don't have "roundabout" projects. E: Design decision - roundabouts at intersections next to a bridge that can eliminate a turn lane on the bridge (both in retrofit and new installations). Likewise on corridors to eliminate turn lanes (narrower corridor). F: These are reasons roundabouts have been proposed or designed, as we have not actually constructed any yet. G: Unknown H: "Usually" for All of the reasons with the exception being lower initial costs Has your state agency installed a roundabout at a location that previously involved one or more fatal crashes in the before condition?

Alaska Arkansas California Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Mexico New York North Carolina North Dakota Oregon Pennsylvania Rhode Island South Dakota Texas Vermont Virginia Washington West Virginia Wisconsin Wyoming State Website Flyer and/or pamphlet Video Other Other Note Our state agency has not developed public outreach material X X X X X X X X X X X X X X X X X X X X X X X X X X X A X X X X X X X X X X X X X X X X X B X X X X X X X X X X C X X X X X X X X D X X X X X X X X X X X X X X X X X X X X X X X X X X E X X X A: Public meetings with displays B: Roundabout mat (scale model); roundabout guidance on state highway map C: Radio and TV public-service announcements D: VISSIM simulations E: Wisconsin Motorist Handbook, TV & radio commercials, video animation, roundabout driver simulator, DVD's, state maps, Commerical Driver's Manual, newpaper articles Please indicate the types of public outreach materials that have been developed by your state agency. Please select all that apply.

Alaska Arkansas California Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Mexico New York North Carolina North Dakota Oregon Pennsylvania Rhode Island South Dakota Texas Vermont Virginia Washington West Virginia Wisconsin Wyoming State Presentations Charts, figures, etc... on display boards Scaled plan sets with vehicle models Attendance from agency staff Attendance from roundabout design team Attendance from "high- ranking" agency official Attendance from traffic engineers involved in the project Attendance from transportatio n planners involved in the project Question and answer session (town hall meeting) Flyer and/or pamphlet Video Video of roundabout simulation Other Other Note Our state agency does not typically use public information open houses for roundabout projects X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X A X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X B X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X A: Roundabout mat, mall kiosk, radio & newspaper ads, bus rides, simulator events B: Design Visualization Please indicate the strategies typically used by your state agency at public information open houses

Alaska Arkansas California Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Mexico New York North Carolina North Dakota Oregon Pennsylvania Rhode Island South Dakota Texas Vermont Virginia Washington West Virginia Wisconsin Wyoming State Mini-Roundabouts Single-Lane Roundabouts Multilane Roundabouts Yes No answer $1,500,000 $3,000,000.00 No No answer $500,000 $1,250,000.00 No No answer $1,500,000 $3,000,000.00 No No answer $1,500,000 $2,000,000.00 No No answer $2,000,000 No answer Yes $50,000 $500,000 $1,200,000.00 No $200,000 $1,200,000 $2,000,000.00 No answer No answer No answer No answer No answer No answer Yes No answer $635,000 $1,400,000.00 No No answer No answer No answer Yes No answer $2,500,000 $4,000,000.00 No No answer $100,000 $200,000.00 No No answer $1,600,000 $3,000,000.00 Yes No answer $1,300,000 $2,500,000.00 Yes $400,000 $1,000,000 $2,500,000.00 No No answer No answer No answer No No answer No answer No answer Yes $160,000 $1,050,000 $1,500,000.00 No $250,000 $2,000,000 $3,000,000.00 No $50,000 $600,000 $800,000.00 Yes No answer $2,000,000 $2,500,000.00 No No answer No answer No answer No No answer $1,500,000 $6,000,000.00 No No answer $1,000,000 $2,000,000.00 No No answer $750,000 $750,000.00 Yes $50,000 $1,000,000 $1,500,000.00 No $250,000 $600,000 $1,000,000.00 No $1,000,000 $2,000,000 No answer Yes No answer No answer No answer No No answer No answer No answer No No answer No answer No answer No No answer $1,000,000 No answer No No answer No answer No answer Yes No answer No answer No answer Yes No answer $1,500,000 $2,500,000.00 No $80,000 $1,250,000 $1,750,000.00 No No answer $400,000 $600,000.00 No No answer $100,000 $1,250,000.00 No No answer $5,000,000 No answer Does your state have state statutes, codes, or laws that regulate traffic rules at roundabouts? More specifically, does your state have state statutes, codes, or laws that are only applicable to roundabouts? What is the approximate planning-level cost estimate (screening or feasibility level estimate) of a roundabout by category in your state? Please limit your responses to "single-purpose" intersection projects.

Alaska Arkansas California Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Mexico New York North Carolina North Dakota Oregon Pennsylvania Rhode Island South Dakota Texas Vermont Virginia Washington West Virginia Wisconsin Wyoming State HCM 2010 Model HCM 2010 Model calibrated to local conditions HCM 2010 Model calibrated to non- local conditions Sidra Standard Model with Environment Factor Sidra Standard Model without Environment Factor UK Equations uncalibrated UK Equations calibrated Microsimulation Other Other Note XX X X XXX X A X X X X X X X X XX X X B X X X X X X X C X XX X D XX XX X X X EXX X X X X XX X X X X X XX X F X X X X X X X XX X X X X X XX X X X X X X X X X X X X XX XX X X X X X X X X X X X X G X XXXX X H X X A: RODEL B: Synchro C: Model used depends on build year or future vs. year evaluation D: Vissim traffic simulation, Synchro SimTraffic E: Equations provided in NCHRP Report 572 F: Rodel, Arcady G: Sidra Standard with no environment factor in design year H: HCM 2010 model calibrated for statewide roundabout analysis based on observed headways What delay/capacity model is used or permitted by your state agency to determine the operational performance of a roundabout? Please select all that apply.

Alaska Arkansas California Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Mexico New York North Carolina North Dakota Oregon Pennsylvania Rhode Island South Dakota Texas Vermont Virginia Washington West Virginia Wisconsin Wyoming State Arcady HCS Rodel Sidra State Agency developed tool (excel spreadsheet or other, please specify) Synchro Vistro Microsimulation Other, please specify in the comments box Comments X X X X X X X X X X XXX X X X A X X XXX X X X A XX XX B X X XXX X X X X X X X X X C X X A X XXX XX X X X X X X X X X D XXX XXX XXX X XX XXXX X X X EX X XX X X FXX X X XX XX XX XXX X AX G XXX X X HXXX XXXX A: Vissim B: GDOT Roundbout Analysis tool is almost always used, so HCS is not used much since the GDOT tool uses the same formulas. Arcady is approved, but rarely used. Sidra is the most common software used. Vissim has been used. C: HCS is main software used. D: Our Road Design Manual recommends use of the UK model (Arcady, Rodel). However, when capacity threshold is in question, we also check and compare with HCM and microsimulation/Vissim results. E: We currently only accept SIDRA analysis for determining LOS or capacity. We will use SimTraffic to see how a roundabout may work in a road network, but do not accept Synchro analysis (v. 7, we are evaluation v. 9.) We did not accept HCM2000, but are evaluating HCM2010. VISSIM and Trans-Modeler have been used for LOS and capacity decisions. F: Excel spreadsheet G: Rodel and Sidra. We don't accept Synchro H: Synchro used in combination with Microsimulation. Rodel has been used in the past. What software tools are used by your state agency to determine the operational performance of a roundabout? Please check all that apply.

Alaska Arkansas California Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Mexico New York North Carolina North Dakota Oregon Pennsylvania Rhode Island South Dakota Texas Vermont Virginia Washington West Virginia Wisconsin Wyoming State Case-by-case basis 5 years 10 years 20 years Over 20 years 20 20 DC 20 20 20 modleSyllausUsemitemoSreveNX 20 20 20 E 25 15-20 20 20 reveNsemitemoSsemitemoSreveNX 20 AXsyawlAyllausU F 20 20 20 modleSyllausUmodleSmodleSX 20 XyllausU G reveNyllausUsemitemoSmodleSX XreveNsyawlAreveNreveN H 20 semitemoSyllausUmodleSmodleSX 20 X XsyawlA 30 IB modleSyllausUyllausUsyawlAX 20 20 20 How is the design year determined? A: 20 year design life; then a phased approach based on 10 year increments B: 20 years for Federal or Interstate projects C: Current year for safety & operational projects; build-out year for local development mitigation projects D: 20 years from construction for new facility or reconstruction (intersection and interchange) E: 20 years or full buildout (30-40 years) F: Typically 20 years for new construction; 10 years for 3R (Resurfacing, Restoration, Rehabilitation) projects G: 10 and 20 - phased in design. 30 if bridge involved. H: 20 years, 10 years for development I: Usually 20 years however with Practical Design, are looking at 10 year windows Case-by-case basis: Please provide us an approximation of how often the following design-year options are used. Practical Design policy Specific criteria, please specify the criteria: Fixed design year, please specify the design year: Fixed duration (e.g. 20 years), please specify the number of years:

Alaska Arkansas California Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Mexico New York North Carolina North Dakota Oregon Pennsylvania Rhode Island South Dakota Texas Vermont Virginia Washington West Virginia Wisconsin Wyoming State Highway Safety Manual predictive methodology: Crash Modification Factors or Crash Reduction Factors (uncalibrated): Crash Modification Factors or Crash Reduction Factors (calibrated to local conditions): Other Other, please specify Our state does not typically estimate or predict safety at roundabouts X X X A X B X X X X X X X C X D X X X X E X X X X X X X X X X X X X X X X X X X F X X X X X X G X X X X X X X X X X X X H X X X X I X How does your state estimate or predict safety at roundabouts? A: Via "collision rate groups" established from our collision database, adjusted for traffic volumes and development conditions (i.e. rural, suburban, urban) B: IIHS study C: The FHWA clearinghouse is typically used D: Our own highway safety analysis program E: Before/After Study F: State evaluation G: Developing crashes per million entering vehicle rates H: In addition to HSM predictive methology, we will rely on early IIHS work for rural locations I: Roundabout safety analyses, phase 1 and 2 (completed; phase 3 forthcoming)

Alaska Arkansas California Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Mexico New York North Carolina North Dakota Oregon Pennsylvania Rhode Island South Dakota Texas Vermont Virginia Washington West Virginia Wisconsin Wyoming State X A X B X X X X X C X D X E X F X G X H X X X X I X J X X K X L X M X X X N X X O X P X X X Q X R X X X S X T X U X Please indicate the extent to which your state agency uses NCHRP Report 672: Roundabouts an Informational Guide, Second Edition to provide roundabout design guidance. Our state uses NCHRP Report 672 as the only source of design guidance. Our state uses NCHRP Report 672 supplemented by material from other sources to provide design guidance. Our state has developed guidance to supplement NCHRP Report 672. Our state has developed separate guidance and does not use, or rarely uses, NCHRP Report 672. Our state uses material from other sources, and does not use, or rarely uses, NCHRP Report 672. A: MUTCD; Memo on design from regional pre-construction engineer B: Kansas Roundabout Guide C: Chapter 8 of the Georgia DOT Design Policy Manual (http://www.dot.ga.gov/PartnerSmart/DesignManuals/DesignPolicy/GDOT-DPM.pdf) D: Indiana DOT - 2013 Design Manual, page 84 (http://www.in.gov/indot/design_manual/files/Ch51_2013.pdf) E: Iowa DOT Design Manual, Chapter 6, Section 6A-3 (http://www.iowadot.gov/design/dmanual/06a-03.pdf) F: Kansas Roundabout Guide - 2nd Edition (https://www.ksdot.org/burtrafficeng/roundabouts/roundabout_guide/roundaboutguide.asp G: NCHRP Report 672; Kentucky Transportation Cabinet Design Guidance (http://transportation.ky.gov/Highway-Design/Memos/Design%2003-10.pdf) H: Louisiana DOT Road Design Manual, Chapter 6, Section 6.9 (http://wwwsp.dotd.la.gov/Inside_LaDOTD/Divisions/Engineering/Road_Design/Road%20Design%20Manual/09%20Chapter%206%20-%20At-Grade%20Intersections.pdf) I: Michigan DOT Roundabout Guidance Document (http://mdotcf.state.mi.us/public/tands/Details_Web/mdot_roundabout_guidance_document.pdf) J: Minnesota DOT Road Design Manual Chpter 12 - Guidelines for Modern Roundabouts (http://dotapp7.dot.state.mn.us/edms/download?docId=1062365) K: Missouri DOT Engineering Policy Guide - 233.3 Roundabouts (http://epg.modot.mo.gov/index.php?title=233.3_Roundabouts) L: NHCRP Report 572 Roundabouts in the United States; Roundabout Design Guidelines, Ourston Roundabout Engineering; Synthesis of North American Roundabout Practice, Transportation Association of Canada M: Roundabouts, An Informational Guide, Publication No. FHWA-RD-00-067; MUTCD, Part 2b & Part 3; NCHRP Report 674, Crossing Solutions at Roundabouts and Channelized Turn Lanes for Pedestrians With Vision Disabilities; Roundabout Design Guidelines, Wisconsin DOT N: Chapters 5, 8, 11, and 18 of the New York State DOT Highway Design Manual (https://www.dot.ny.gov/divisions/engineering/design/dqab/hdm) O: FHWA; AASHTO P: Oregon DOT Highway Design Manual (ftp://ftp.odot.state.or.us/techserv/roadway/web_drawings/HDM/2011%20HDM%20Rewrite/2012%20Chapter%208%20Intersections.pdf); Oregon DOT Roundabout Directive DES-02 (http://www.oregon.gov/ODOT/HWY/TECHSERV/docs/pdf/des_02.pdf); Oregon DOT Traffic Manual, Section 6.26 (http://www.oregon.gov/ODOT/HWY/TRAFFIC-ROADWAY/docs/pdf/traffic_manual_13.pdf); Oregon DOT Analysis Procedure Manual (http://www.oregon.gov/ODOT/TD/TP/Pages/apm.aspx) Q: South Dakota DOT Road Design Manual, Chapter 12 (http://sddot.com/business/design/docs/rd/rdmch12.pdf) R: Texas Roundabout Guidelines: Final Report (https://www.utexas.edu/research/ctr/pdf_reports/0_6414_1.pdf) S: Washington DOT Design Manual, Chapter 1320 (http://www.wsdot.wa.gov/publications/manuals/fulltext/M22-01/1320.pdf) T: AASHTO, A Policy on Geometric Desgin of Highways and Streets "Green Book" U: Wisconsin DOT Facilities Development Manual, Chapter 11, Section 26 (http://wisconsindot.gov/rdwy/fdm/fd-11-26.pdf#fd11-26) Please indicate the sources used for design guidance.

Alaska Arkansas California Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Mexico New York North Carolina North Dakota Oregon Pennsylvania Rhode Island South Dakota Texas Vermont Virginia Washington West Virginia Wisconsin Wyoming State Does your state agency typically try to use a phased implementation approach to multilane roundabouts? (This could include opening a roundabout with fewer entry, circulating or exit lanes than is ultimately determined to be necessary for future conditions.) Do you have criteria for determining when a phased-implementation approach should be used? Please indicate the criteria used for determining when a phased-implementation approach should be used. Have one or more roundabouts in your state (built by your state agency or others) designed with a phased approach in mind been expanded from its opening-year configuration? Have one or more roundabouts in your state (built by your state agency or others) designed with a phased approach in mind been expanded from its opening-year configuration?: Comments Yes No No Yes Yes A No Yes Yes No No No Yes No Yes Yes Yes B No N/A N/A No Yes No No Yes Yes C No Yes No No Yes Yes D No No Yes Yes E Yes M No Yes Yes F No Yes Yes G No No Yes No No Yes No H No No No Yes No No Yes No No Yes Yes I No Yes Yes J No No Yes No No No No N/A No No Yes No No Yes K Yes N Yes Yes L No Yes No Phased implementation approach to multilane roundabouts A: It's a case-by-case basis. Modeling is used to project traffic volumes for opening date and 20 year design. Implementation of lane geometry is phased accordingly. B: If the roundabout will work as a single-lane roundabout for approximately 10 years or more (based on capacity analysis), Georgia DOT opens it as a single-lane roundabout with removable portions for the future multi-lane configuration. C: Documented in Section 6.1.3 of the Kansas Roundabout Guide, 2nd Edition D: Analysis output from software. E: If a single-lane configuration will be sufficient for five years or less Maryland SHA will proposed a multilane configuration. If the single-lane configuration is sufficient for more than ten years, SHA will open as a single-lane roundabout. In between five and ten years is decided on a case-by-case basis. F: Evaluated on a case-by-case basis depending on the expected traffic volume growth between the opening and design years. G: If the roundabout will work as a single-lane roundabout for approximately 10 years or more (based on capacity analysis), Michigan DOT opens it as a single-lane roundabout, and waits for future phased construction. Michigan DOT also coordinates the single-lane and multilane designs to minimize future reconstruction. H: Depends on future capacity needs, and is determined on a case-by-case basis. I: The roundabout is opened as a single-lane roundabout designed with expansion in mind when New York State DOT predicts a single-lane roundabout will get ten years of acceptable operations, but fail before 20 years J: For long-range projects, a design year (currently 2040) analysis is done to determine ultimate design. If this design calls for multi-lane approaches or slip lanes, North Carolina DOT will conduct an interim analysis to see if fewer lanes will work for at least ten years or so. K: The use of a phased-implementation approach is site specific and left up to the judgment of the traffic engineers working with the expected traffic volumes in collaboration with program or project offices involved in developing the project footprint. L: The use of a phased-implementation approach is sometimes based expected traffic volumes (opening-year volumes versus subsequent future-year volumes) or could be to align future expansion with other roadway work M: I-495/Ritchie Marlboro Road interchange ramp terminals N: SR 166/ Bethel Avenue - Port Orchard; SR 501/45th Street - Ridgefield; Boulevard Road/Log Cabin - Olympia

Alaska Arkansas California Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Mexico New York North Carolina North Dakota Oregon Pennsylvania Rhode Island South Dakota Texas Vermont Virginia Washington West Virginia Wisconsin Wyoming State Have one or more roundabouts in your state (built by your state agency or others) been modified from its original design to address safety or operational issues? Have one or more roundabouts in your state (built by your state agency or others) been modified from its original design to address safety or operational issues?: Comments Yes A No Yes B No Yes C Yes D Yes E No Yes F Yes G Yes H No Yes I Yes J Yes K Yes L Yes M No No No Yes N No No No Yes O Yes P No Yes Q No No No No No Yes R Yes S Yes T Yes U Yes V Roundabouts modified from its original design to address safety or operational issues A: Dowling/New Seward Highway intersection in design B: State Highway Route 1/Simpson Lane intersection in Mendocino County was modified from a "hybrid" to a single-lane configuration. C: A roundabout was modified becaues of issues with oversized farm vehicles in a rural area. The roundabout was significantly modified with larger/less steep apron, more clear area on the outside of the roundabout, and less steep curbs D: Clearwater, Florida E: Georgia DOT added a truck apron to a roundabout near Gainesville College and modified truck aprons on roundabouts in Culloden and Carrollton due to design vehicle issues F: US 34/US 63 in Ottumwa G: US-50/I-35 interchange in Emporia, Kansas H: The signing and pavement markings of a multilane roundabout were modified by a local jurisdiction I: The first roundabout built by the Maine DOT did not have a raised truck apron which was added in subsequent years J: Many early roundabouts have been modified K: Rotaries have been retrofit with roundabout-style markings to improve safety and reduce delays. L: M-53/18 ½ Mile Road intersection had revisions to the central island and signing. Other roundabouts have had slight modifications, typically including signing and pavement markings M: TH61/Broadway Ave, Forest Lake, MN; CR13 (Radio Dr)/CR18 (Bailey Rd), Woodbury, MN; I-35/CR12 (69th ST NW) interchange N: Multilane roundabout with three lanes at the intersection of 14th Street/Superior Street built by the City of Lincoln was reduced to two lanes. O: So far just signing, striping, and lane assignment modifications. New York State DOT will likely start reducing lanes based on growth rate predictions not coming to fruition. P: Hillsborough St. at Pullen/Oberlin intersection in Raleigh. Built as a multi-lane roundabout, within 12 months after opening, over 120 crashes occurred. An evaluation was made, and volumes were not as high as originally planned. Lanes were then changed (to right-turn lanes, or eliminated) so that only single through lanes were provided, along with some minor alignment changes. Other roundabouts have had minor adjustments (for instance, outside curbs installed instead of shoulders to reduce rutting.) Q: Striping and signing modifications have been made to the multi-lane roundabout near Astoria at the intersction of US 101/OR 202 to improve sight lines and driver behavior. R: US 50/US 15 intersection (Gilbert's Corner) in Loudoun County S: SR 510/Pacific Avenue intersection was striped to reduce capacity; SR 16 Southbound Ramp/Borgen Blvd intersection was restriped and the capacity reduced to correct a design flaw involving back to back double left movements T: The lane configuration was adjusted on one approach at the roundabout at the intersection of WV 705/US 119 in Morgantown U: Broadway Street (STH 32/57) roundabout in De Pere was modified to accommodate dual northbound left-turns and lower volume eastbound through and left movements V: Paved the inner circle to allow Oversize/Overweight loads to navigate the intersection on a hard surface

Alaska Arkansas California Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Mexico New York North Carolina North Dakota Oregon Pennsylvania Rhode Island South Dakota Texas Vermont Virginia Washington West Virginia Wisconsin Wyoming State Has your state developed guidance on the accommodation of large vehicles (trucks, emergency vehicles, farming equipment, oversize/overweight vehicles, etc...) at roundabouts? Yes, please provide the document name where we can find the information:Is the design-vehicle accommodation guidance provided in the material uploaded in question 19? Yes No Yes A No Yes No Yes B Yes C Yes D Yes E Yes F Yes No No No No Yes G No Yes H No Yes No No No Yes I No No Yes J No No Yes K No No Yes L Yes M No Yes N Yes Guidance on the accommodation of large vehicles (trucks, emergency vehicles, farming equipment, oversize/overweight vehicles, etc...) at roundabouts? A: California Highway Design Manual, Chapter 400 B: Information included in Chapter 8 of the Georgia DOT Design Policy Manual (http://www.dot.ga.gov/PartnerSmart/DesignManuals/DesignPolicy/GDOT-DPM.pdf) C: Indiana DOT - 2013 Design Manual, page 115 (http://www.in.gov/indot/design_manual/files/Ch51_2013.pdf) D: Iowa DOT Design Manual, Chapter 6, Section 6A-3 (http://www.iowadot.gov/design/dmanual/06a-03.pdf) E: Kansas Roundabout Guide - 2nd Edition (https://www.ksdot.org/burtrafficeng/roundabouts/roundabout_guide/roundaboutguide.asp F: Kentucky Transportation Cabinet Design Guidance, page 6&7 (http://transportation.ky.gov/Highway-Design/Memos/Design%2003-10.pdf) G: Minnesota DOT Road Design Manual Chpter 12 - Guidelines for Modern Roundabouts (http://dotapp7.dot.state.mn.us/edms/download?docId=1062365) H: Accommodating Small and Large Users at Roundabouts (http://www.ghd.com/pdf/roundabouts-TAC2009-Small-and-Large-Users-at-Roundabouts.pdf) I: Draft Highway Design Manual 26.4.5 tells designers to determine appropriate design vehicle. If Oversize/Overweight, designers will need to contact Main Office for assistance J: Oregon DOT Roundabout Directive DES-02 (http://www.oregon.gov/ODOT/HWY/TECHSERV/docs/pdf/des_02.pdf); soon in the ODOT Highway Design Manual, Chapter 8 K: South Dakota DOT typically designs for the WB-67, however, they have designed roundabouts to accommodate longer combination vehicles (LCVs). See page 12-15 (http://sddot.com/business/design/docs/rd/rdmch12.pdf) L: WB-67 vehicle M: Washington DOT Design Manual, Chapter 1320 (http://www.wsdot.wa.gov/publications/manuals/fulltext/M22-01/1320.pdf) N: Wisconsin DOT Facilities Development Manual, Chapter 11, Section 26, Sections 10.2 & 30.5.4 to 30.5.7 (http://wisconsindot.gov/rdwy/fdm/fd-11-26.pdf#fd11-26)

Alaska Arkansas California Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Mexico New York North Carolina North Dakota Oregon Pennsylvania Rhode Island South Dakota Texas Vermont Virginia Washington West Virginia Wisconsin Wyoming State AASHTO Roadway Lighting Design Guide IES Design Guide for Roundabout Lighting NCHRP Report 672 State-specific standard Other Other, please specify Yes X X X X A Yes X X X Yes BX Yes X X Yes Yes XX Ye CXXXXXs Yes X X D No Yes EX Yes X Yes X F No Yes X Yes X X Yes X Yes X X GX Yes X X Yes HXX Yes X X Yes X X X Yes X Yes X X X Yes X X X I Yes X J Yes X Yes X Yes X X No Yes X K Yes X LX Yes X Yes X Yes MX Yes X X Yes X X Yes X What is the basis for your state's illumination standard/guidance? Illumination standard/guidance Does your state follow developed standards/guidance on the illumination of roundabouts? A: AASHTO's "An Informational Guide for Roadway Lighting" 1984 B: California Highway Design Manual, Chapter 400 C: Chapter 8 of the Georgia DOT Design Policy Manual (http://www.dot.ga.gov/PartnerSmart/DesignManuals/DesignPolicy/GDOT-DPM.pdf) D: Indiana DOT - 2013 Design Manual, page 134 (http://www.in.gov/indot/design_manual/files/Ch51_2013.pdf) E: Kansas Roundabout Guide - 2nd Edition (https://www.ksdot.org/burtrafficeng/roundabouts/roundabout_guide/roundaboutguide.asp F: Louisiana DOT uses the IES Design Guide for Roundabout Lighting. They do not require roundabouts to be lit. G: Roundabouts: An Informational Guide 1st Edition; Roadway Lighting Design Manual (http://www.dot.state.mn.us/trafficeng/lighting/2010_Roadway%20Lighting_Design_Manual2.pdf) H: http://epg.modot.mo.gov/index.php?title=Category:901_Lighting I: Draft Highway Design Manual 26.6.2. J: The Roadway Lighting gropu uses AASHTO Roadway Lighting Design Guide solely in roundabout lighting design in TIP projects and in roundabout lighting design encroachments review. For roundabouts located in continuously illuminated roadways, the roundabout should be lit to a level that is 2 the value used on the best lit approach. This design light level is in general agreement with NCHRP 672. For roundabouts with unlit connecting roadways, the roundabout should be lit to a level that is 1.3 times the value of the connecting roadway with highest roadway classification. K: South Dakota DOT Road Design Manual, Chapter 12, page 15-29 (http://sddot.com/business/design/docs/rd/rdmch12.pdf) L: ANSI RP-8-00 M: Washington DOT Design Manual, Chapter 1320 (http://www.wsdot.wa.gov/publications/manuals/fulltext/M22-01/1320.pdf) N: Wisconsin DOT Facilities Development Manual, Chapter 11, Section 11, (http://wisconsindot.gov/rdwy/fdm/fd-11-26.pdf#fd11-26)

Alaska Arkansas California Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Mexico New York North Carolina North Dakota Oregon Pennsylvania Rhode Island South Dakota Texas Vermont Virginia Washington West Virginia Wisconsin Wyoming State They are not part of design standards used by our agency Not sure they work efficiently Not sure they are safe Not sure that the drivers will get used to them Concerned about liability issues Other Other, please explain Is your agency considering the construction of roundabouts? X X A Yes What are the major reasons why your agency has not built roundabouts on the state system? A: Tradition

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TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 488: Roundabout Practices summarizes roundabout policies, guidance, and practices within state departments of transportation (DOTs) as of 2015. The synthesis may be used as a reference for state agencies that are creating or updating their roundabout and intersection control policies.

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