From written comments on sheets picked up after the oral discussion:

Question 2: as a profession, what don't we know (or know enough about). In regard to good  planning, designing, constructing roundabouts with roundabout operation?
What research or studies do  you need to find out? (Brief needs statement or title)

• Change in public perception needed. How do we do that?
• How do we engage the media to do positive stories?
• How do we convince public agencies to take the next steps?
• We need. Better signing standards – consistency.
• We need to – Consider safety first and then efficiency and reducing congestion.
• We need to – Build single Lane roundabouts first to be more safe.
• We need – More case studies.
• We need – Drivers handbooks and more emphasis on how to drive roundabouts.
• We need – More outreach to natural allies, for example, environmentalists, public health, new urbanists [ new urbanism?], American planning Association and so forth.
• We need to – Find more champions of the cause.
• We need to – Fix  rotaries and other poorly performing circles to improve perception, even if it's a new [roundabout].
• We need to – Build a schedule of presentations to elected officials or associations of elected officials.
• We need to. Develop higher-quality materials geared to better public understanding of roundabouts.
• We don't know how much driver behavior is affected by geometry and layout.
• We don't know about driver workloads when driving through roundabouts or series of roundabouts.
• Case studies are useful but research on all aspects involved in roundabouts should be considered necessary (at a high level of detail).  Reemphasize guidelines over warrants.
• We don't know How to achieve yielding behavior.
• We don't know  about Tools for enforcement.
• Research: Cyclist impacts to operation, needs and multilane roundabouts, correct Lane placement, multilane entry and inside vehicle with site blocking.
• Research efforts and studies: presentation templates to tailor to local area and provide outreach to partners such as active living, new urban green initiatives, reduce our “silent partner” status. Air quality models.Emergency responder needs defined instead of demands.
• We don't know about traffic signals at roundabouts (metering and/or full operation and or the Hawk system) or all applications such as pedestrians, meters and so forth. Also, design parameter thresholds  where geometry is no longer enough. Application of Turbo roundabouts in the United States.
• Research: The impact of education campaigns of all classes such as children, high school, adults, and senior citizens.  Accommodation of equestrians, animation other user groups. Adding and dropping maintenance – capacity and design implications. Best practices for data collection. US capacity for mini roundabouts.
• We don't know all actual capacity results experience in the USA or individual country versus capacity equations (calibration like 1.2 environmental factor for HCM values).
• More public education of signage and operations of roundabouts is needed, i.e. public safety announcements on TV, roundabout coloring books are also good. We need more consistency between driver education and driver license booklets versus the MUTCD signage and pavement markings.
• We need to know more about multilane roundabout footprints and their use by putting in single Lane roundabouts marked with the inner Lane as the truck apron then we can add an actual truck apron in the center island in the future for the two Lane roundabout in the future. Therefore, you have utilities and the right-of-way already covered for future two-lane roundabouts and the tightest curves for roundabouts already covered.
• Research: safety research studies of existing state Route roundabouts and local roundabouts versus signalized intersections. Multidirectional, raised snow probable pavement markings to use long inside of roundabout curbing (to provide retroreflectivity of similar dome reflectors used in Florida.
• Research: investigate over signing of pedestrian crossings at roundabouts create inconsistencies with the overall pedestrian crossings policy and practice.
• What we don't know: pedestrian safety when one vehicle yields but a vehicle in the other lane does not. Roundabout percept ability prior to getting to the stop sign. I.e. central island design. Consistency between design models.
• Research needs: extension of design models to include more than geometric considerations. Study of perpendicular versus acute approaches, especially for older drivers who can't turn their heads as far. Also, perpendicular approaches may reinforce that you need to yield to both lanes, for example, in a dual Lane roundabout.
• We don't know how to educate roundabout users better. We are engineers and not teachers or public relations experts.
• Need to know more about concerns about spot treatments: initial implementation in “new to roundabout”; looking at road character and nearby intersection (especially corridors); Adam Kirk at KTC mentioned targeting successes instead of looking for failures; and balancing restraint versus enthusiasm for roundabout implementation.
• We need to know: short term build versus long-term planning, i.e., build in versus build out. Driver behavior studies showing roundabouts forced drivers to pay attention. For example, eye tracking. We need to show speeds in simulation model software. We need to know more about central island landscaping and its value to safety and sight distance to the left and improve safety restrictions. We need to know more about actual versus concrete in and circle and about long-term maintenance. We need more human factor studies. I.e., distance of ramp [something unreadable] to the circle.
• The top four we need to know or know more about: educating officials and marketing roundabouts. Pedestrian safety and operations. Bicycle safety and operations. The impact of the highway capacity manual on capacity and also the lighting of mini roundabouts.
• We  need more information on reverse superelevation and how it affects large trucks. We need to know how roundabouts affect downstream roads and intersections. We need to know more about whether there are too many signs and options for roundabouts, for example, is there too much clutter in regard to signing and pavement markings. We need to know more about the HAWK system and the Rapid Flashing Beacon. We would like to see the Rapid Flashing Beacon research. [ Comment by gene – I would like to see some research to develop a rapid flashing Beacon that has a red beacon following the yellow beacon, similar to the HAWK- and I know the correct name is pedestrian hybrid beacon ] How do bus stops fit into roundabouts. Concerned about diagrammatic signs.
• One. We don't know enough about signing and marking and lighting. We need standards, which helps with public perception and minimizing confusion. We need to know more about when roundabouts are not appropriate in relation to trucks? Volume? Capacity issues? And metering? We need to know when cost is justified for improvements. For example what threshold of the benefit cost number justifies a roundabout? We need to know more about how all large vehicles operate in their Lane or straddling the Lane and about  geometric and signing improvements.
• We need to know about what capacity and volume  projections we should use for the design year. Where is a reasonable number? Should we consider ranges instead of a single number?
• We do know if current methodology provides a fair comparison between traditional intersections and roundabouts?
• There is a major uncertainty about the operation and safety aspects of multilane roundabouts.
• We need to know the best practices in regard to bicycles and roundabouts safety.
• There is a lack of data and old data for roundabout analysis.
• We need to know more about planning and promotion of roundabouts. About the design of roundabouts. About contractor expertise during construction and layout. And about competition in modeling.[ gene comment- I have no idea what the last means,unless  it means what I wonder about and that is, there are so many vendors selling their (one of many) model and claiming their model is the best, how does one decide which one really is? I think we need a lot more research on model output versus field “reality” then we can determine which one or ones best fit field conditions. As it is all we seem to be able to compare is one to the other which is like comparing two random numbers].
• We need to know more about ADA visibility issues. More about software traffic models and their calibration in which one to use. More about grading and drainage. More about signage in regard to Lane assignment combined with naming and fishhooks.
• We need to more more about capacity comparing models to reality. We need to know more about bicycles, for example,  how to accommodate and protect them  in roundabouts and do multiuse paths [ I assume this means when the bicyclist uses a bicycle ramp and uses the sidewalk ] introduce cyclist and pedestrian conflicts. The jury is still out on bicycle and roundabout use.
• Need to know more about multilane roundabouts and trucks.
• We need to know more about paint marking consistency. Pavement markings should not be a crutch for [poor?] physical attributes.
• We need to know more about the blind pedestrian issues in regard to safety and accessibility.
• We need to know more about capacity analysis for example which is best – calibrating simulations that were designed for freeways and/or signal intersections  there[gene comment – not clearly neither].
• We need to know more about practitioners looking for and wanting to rely on American data sets and experiences and research.
• How do we standardize and practice roundabout design when there is more art than prescriptive language, forms, and so forth are in the design guide?
• How do we cover in a professional advisor role to policy makers and supporting interest like trucks, blind, and emergency response?
• Roundabout people here are not the “roundabout only  ” folks back home.  Determine environmental benefits to gain partners. Need practices for construction and maintenance. Get colleagues and partner agencies to at least consider roundabouts.
• We need to know more parameters for current USA drivers and what values to use for future drivers 20 years out. We need to know why do more pedestrians and cyclists crashes occur at the exits versus entriance? We need more research on this. We need to know more about the safety performance functions of roundabouts [ gene comment. I suppose this means what aspects of geometry ,signing and marking -and maybe some other things -contribute to safety].
• There is need for flexible guidance for regional variations in climate, population density, aesthetics and vehicle – non motorized mix, for example, bollards in snowy areas.
• We need to know more about pedestrians, capacity issues crash and safety issues, modeling guidance, bicycle and transit issues.
• Research: in regard to capacity We need to collect more data and analyze capacity more in detail.
• We need more information on where to place pedestrian crossings in relation to the circulating roadway. More about large vehicles. More about where to place roundabouts, i.e. they are not for every place.
• Research: We need more studies on capacity analysis, including a large network analysis and more pedestrian safety studies.
• We need to know what is the warrant for pedestrian signals at a roundabout? What pedestrian volume? We need a USA model for capacity for example does the HCM account for all issues? We need more Lane assignment marking and signing.
• We need more driver education for two-lane roundabouts so that drivers understand they're not at a traffic circle. We need to know how to make it clear that drivers must yield to both lanes from the left when entering.
• We need that leave engineering for design, for example, splitter lengths, curb limits, minimizing costs without reducing safety and performance.
• We need to know more about design for older drivers, pedestrians and cyclists. We need to know more about truck behavior in roundabouts. We need to know more about roundabout operation in snowy and cold regions i.e. where drivers cannot see the pavement markings and  delineation. We also need to know more about maintenance requirements from  snow plowing.