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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>STREET SYSTEMS AND CLASSIFICATIONS TO SUPPORT SMART GROWTH</title>
      <link>https://trid.trb.org/View/755618</link>
      <description><![CDATA[This paper presents concepts on street systems to support Smart Growth that are being developed through a joint project of the Institute of Transportation Engineers and the Congress for the New Urbanism.  The intent of the joint project is to encourage the practice of context sensitive street and network design to create and strengthen multi-modal places, to emphasize walkability, and to support compact, mixed use environments. Within the current practice of street design, network density and functional class are used as inputs to the design process to control the basic size, speed, and accessibility of the roadway being designed.  In that context, the network aspects focus on minimizing travel time and congested operations, rather than on defining their contribution to community character.  Similarly, while the functional class system establishes the hierarchy for street networks, it remains silent on the size, scale, and modal accommodation of the various roadways in each classification by leaving that activity to a capacity-based needs calculation. The joint project work establishes a dimensional framework that pairs a street typology (modes accommodated, purpose) and design criteria (maximum number of lanes and design speed) with urban design (levels of activity, location of access, relation to street) to create coherent networks that serve the diverse economic, social, and environmental needs of metropolitan communities.]]></description>
      <pubDate>Fri, 08 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755618</guid>
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      <title>DESIGN GUIDANCE FOR GREAT STREETS: ADDRESSING CONTEXT SENSITIVITY FOR MAJOR URBAN STREETS</title>
      <link>https://trid.trb.org/View/755619</link>
      <description><![CDATA[This paper presents the progress of a joint project of the Institute of Transportation Engineers (ITE) and the Congress for the New Urbanism (CNU).  Together, the two organizations are working to prepare guidance for context sensitive design of major urban streets, drawing on principles and techniques from the new urbanist and smart growth movements.  New urbanism is a movement in planning, design and development that is re-establishing compact, walkable and environmentally sustainable neighborhoods, cities and towns.  Smart growth is an approach to development and conservation that advocates, among other objectives, strengthening and directing development toward existing communities and fostering distinctive and attractive places.  Streets that are both beautiful and functional -- great streets -- will advance the objectives of both movements as well as the practice of context sensitive design.  In addition to addressing design criteria in the project's deliverables, CNU and ITE will be working in three areas crucial to implementation of their principles at scales from the region to the building: network design; understanding of context and community character; and revisions to the functional class system.  Work on these topics by a multidisciplinary group of CNU and ITE member-practitioners is in its earliest stages.  This paper introduces the project in its "project history and overview" section and then presents findings of initial work on a literature review being conducted as a project start-up task. The emphasis of the literature review is evaluation of conventional and innovative street design resources to assess their contributions to the project's aims.]]></description>
      <pubDate>Fri, 08 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755619</guid>
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      <title>OPERATIONAL EFFICIENCY OF ROUNDABOUTS</title>
      <link>https://trid.trb.org/View/755620</link>
      <description><![CDATA[The Kansas Department of Transportation became interested in roundabouts in 1998 and started designing and building roundabouts on state highways in Kansas.  They sponsored three research projects to get before and after data at several Kansas roundabout locations.  These studies are still ongoing at Kansas State University.  Concurrently, the traffic engineer in the city of Manhattan, when confronted with a high crash rate at the intersection of two residential collector streets with two-way stop control, chose a roundabout over other options.  The city co-sponsored a project with Mack Blackwell Transportation Center to compare the traffic operations of the roundabout with other options.  The Insurance Institute for Highway Safety funded an additional project to get before and after data and analyze operation of roundabouts in Hartford County, Maryland, Hutchinson, Kansas, and Reno, Nevada.  The paper reviews the data collection and analysis techniques and presents results of several comparisons of roundabouts to other types of traffic control that show that the roundabout is superior to almost every other type of traffic control based on the measures of effectiveness used.  The authors present the results of their analysis that led them to conclude that roundabouts are the safest and most effective type of intersection traffic control available today.  The paper also presents a brief review of some public opposition.]]></description>
      <pubDate>Fri, 08 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755620</guid>
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      <title>USE OF ROUNDABOUTS IN AN URBAN SETTING</title>
      <link>https://trid.trb.org/View/755621</link>
      <description><![CDATA[Decades ago, Farmington Avenue in Hartford, Connecticut was an elegant thoroughfare on which Mark Twain, Harriet Beecher Stowe and other notables had their homes.  While the Twain and Stowe houses remain as major tourist attractions, the Avenue is now a major arterial, carrying heavy automobile, bus, truck and pedestrian traffic, and home to major corporate offices, professional offices, small retail businesses, multi-unit residences, restaurants, and gas stations.  It retains only a glimmer of its former elegance and is considered dangerous because of large volumes of speeding traffic.  The Farmington Avenue Alliance, a coalition of residential, business and institutional stakeholders, was formed in 1996 with a mission to revitalize Farmington Avenue.  The coalition hired an urban planning consultant who presented a conceptual plan embodying the new Farmington Avenue to the community in early 2002.  While most of the plan was met with enthusiasm, there was concern over the three roundabouts at major intersections recommended by the consultant.  This paper discusses modern roundabouts: what they are and what they are not, safety and traffic flow issues, and how pedestrians are accommodated.  It describes the work the Alliance is doing to address community concerns and build public support for the plan.  This is an ongoing process, which will ultimately lead to a "new" Farmington Avenue.]]></description>
      <pubDate>Fri, 08 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755621</guid>
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      <title>FIELD OBSERVATIONS OF PATH AND SPEED OF MOTORISTS AT DOUBLE-LANE ROUNDABOUTS</title>
      <link>https://trid.trb.org/View/755622</link>
      <description><![CDATA[Roundabouts generally have fewer crashes and less severe crashes compared to signalized intersections.  Reduced speed and low speed differences between entering and circulating traffic are thought to be important contributors to roundabout safety.  The geometric design of modern roundabouts has many attributes that may influence drivers' selection of path and speed.  Deflection at entry is one of the attributes that contributes to both the reduced speeds and low speed differences.  The Federal Highway Administration (FHWA) publication "Roundabouts: An Informational Guide" suggests a method, based on the theoretical fastest path, for evaluating geometric designs for adequacy in controlling speed and speed differences.  The current study evaluated that method against observations of path and speed at two double-lane roundabouts.  The results suggest that the method given in the FHWA publication predicts actual operational speed fairly well. A method is described for recording speed and path through approach, circulatory roadway, and departure.  This method provides for economical recording of lane position at five locations along a through path, and spot speed at three locations.]]></description>
      <pubDate>Fri, 08 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755622</guid>
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      <title>SIGNING AND PAVEMENT-MARKING STRATEGIES FOR MULTI-LANE ROUNDABOUTS: AN INFORMAL INVESTIGATION</title>
      <link>https://trid.trb.org/View/755623</link>
      <description><![CDATA[Multi-lane roundabouts present motorists with a complex set of decisions.  Unlike single-lane roundabouts, for which the only rule on entry is "yield to the driver on your left, then circulate to your right," multi-lane roundabouts also require decisions about lane positioning--and these decisions are necessary at multiple points: entering, circulating and exiting. Many American motorists are not educated on the proper way to negotiate a multi-lane roundabout, and don't always know which lane is correct for making a given movement.  As roundabouts have become more common in the United States over the past several years, resolving driver confusion has become an important task for the designer.  An important question to answer, therefore, is:  What design features can maximize clarity for motorists?  Signing and pavement marking are perhaps the two most important tools designers can use to simplify driver understanding of multi-lane roundabouts.  Jurisdictions across America and abroad have employed a variety of philosophies and approaches in signing and marking multi-lane roundabouts, ranging from minimal to elaborate treatments.  This variation in practice, coupled with the relative lack of published guidance, provides evidence that the industry remains in an "experimental" phase and further standardization may be helpful.  This paper examines and categorizes many of these signing and marking strategies.  Arguments for and against the underlying design philosophies are presented, and general conclusions are drawn regarding the effectiveness of the various approaches.  The paper also recommends future research, with an eye toward establishing reasonable and intuitive uniformity in signing and pavement-marking practice.]]></description>
      <pubDate>Fri, 08 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755623</guid>
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      <title>CONTEXT SENSITIVE DESIGN CHALLENGES FOR MAJOR SUBURBAN ARTERIAL STREET PROJECTS</title>
      <link>https://trid.trb.org/View/755624</link>
      <description><![CDATA[The functional design objectives and requirements for major suburban arterial street projects have dramatically expanded for the 21st Century.  Major suburban streets should address more than just capacity and safety for motor vehicles.  Most suburban areas are highly congested, lack alternatives for developing new highway corridors, and are struggling to improve livability for urban dwellers.  Therefore, 21st Century functional designs for major suburban streets should consider accommodations for auto traffic, freight movement, transit mobility, bicycles, and pedestrians while enhancing livability.  Arterial reconstruction projects are also viewed as an opportunity to drive economic redevelopment and improvement in communities.  Urban design amenities, landscaping, street trees and public art are now part of the comprehensive design.  Pedestrian comfort and safety are important and pedestrian crossings are vital considerations. The challenge now is how to consider these competing needs while addressing traditional highway geometric design guidelines. Many of the design features now being considered for inclusion in suburban street projects may conflict with traditional design guidance.  Eight controversial design features are addressed in light of the context need, traditional design guidance, and design analysis considerations.  The eight design features are: Street Trees and Other Vertical Obstructions; U-turn Accommodations; Transit Lane In-Lane Stops; Pedestrian Refuges in Medians; Signalized Pedestrian Crossings; On-Street Parking; Smaller Radii Intersection Corners; and Reduced Lane Widths. This paper shows how context sensitive design considerations can be applied to accommodate emerging functional objectives while addressing context needs, design guidance, analyses and documentation.]]></description>
      <pubDate>Fri, 08 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755624</guid>
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      <title>CHARLOTTE'S URBAN STREET DESIGN GUIDELINES: A CONTEXT-SENSITIVE DECISION-MAKING METHOD</title>
      <link>https://trid.trb.org/View/755625</link>
      <description><![CDATA[As part of the City of Charlotte's Smart Growth strategy, staff and consultants are developing comprehensive new urban street design guidelines to be applied to all new and modified streets. The design guidelines provide for all travel modes, while explicitly considering land use context, street function, and allocation among competing uses for often-limited right-of-way. The design guidelines offer direction on planning and designing for five street types and their intersections.  As important as the "ideal" cross-sections developed, however, is the information provided to guide the tradeoff decisions inherent in street design, particularly in retrofit or modification situations.  To that end, the guidelines include a step-by-step approach to their application.  The approach is to be used by land planners, traffic engineers, urban designers and any other stakeholders when faced with accomplishing a variety of objectives within constrained conditions.  A test application to a street improvement project demonstrates how the new method has resulted in an alternative street design that would not have been as likely under the traditional approach to street design in Charlotte.]]></description>
      <pubDate>Fri, 08 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755625</guid>
    </item>
    <item>
      <title>DESIGN CHANGES FOR LIVABLE URBAN STREETS</title>
      <link>https://trid.trb.org/View/755626</link>
      <description><![CDATA[The City of Charlotte, North Carolina is in the process of doing a major revision of its design guidelines to create context sensitive streets that address the mobility needs of vehicles, pedestrians and bicyclists.  The goal is to create livable streets.  The new guidelines will serve as an overlay to the entire range of street categories from thoroughfares to locals. The new typology overlay considers five basic land use related context facility types defined as parkways, boulevards, avenues, main streets and local neighborhood access streets.  Each typology is defined to reflect street function and surrounding land uses.  Parkways are seen as aesthetically treated roadway conduits with a design priority of moving traffic.  In comparison, Main Streets are treated with a design priority of moving pedestrians and providing parking for adjacent development.  This change in design philosophy stays in compliance with roadway design standards but addresses the standard engineering need of using 'desirable' values, which in some cases can result in hostile environments for other users. Instead, allowable and minimum standards are used as appropriate to balance user needs to provide a context sensitive street.  The resulting guidelines acknowledge that vehicular congestion can be acceptable for specific roadway typologies and unacceptable for others.  This emerging design philosophy addresses the need to prioritize tradeoffs in street design to permit roadway corridor elements to fit within constructed right of ways based on their function and land use components. Depending on the facility, sidewalks and planting strips can be more important than additional lanes of traffic or their standard 12-ft widths depending upon modal emphasis.  The guidelines address all the elements of basic roadway segments as well as the elements of intersection junctions between similar and different typology facilities.]]></description>
      <pubDate>Fri, 08 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755626</guid>
    </item>
    <item>
      <title>LEFT-TURN LANE INSTALLATION GUIDELINES</title>
      <link>https://trid.trb.org/View/755627</link>
      <description><![CDATA[The addition of a left-turn lane can improve the operations and safety at an intersection.  Guidelines as to when to include a left-turn lane in intersection design are plentiful.  Because of the quantity of methods, questions are asked regarding which method to use.  This paper reviewed eight selected techniques and a number of criteria present in state manuals.  Methods based on delay typically do not recommend a left-turn lane at lower left or through volumes when compared to methods based on conflict avoidance or safety.  Because of the high benefits for crash reductions provided by left-turn lanes, a method that results in a recommendation at lower volumes would be preferred. The Harmelink model is a widely accepted approach that is based on conflict avoidance.  The procedure was first proposed in 1967 and includes assumptions that may need to be revised.  Findings from current research would suggest a critical gap of 5.5 sec (rather than 5.0 sec), a time to make left turn of 4.3 sec (rather than 3.0 sec), and a time to clear the lane of 3.2 sec (rather than 1.9 sec).  A table was developed that lists suggested guidelines for installing left-turn lanes for operating speeds of 30, 50, and 70 mph (50, 80, and 110 km/h).]]></description>
      <pubDate>Fri, 08 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755627</guid>
    </item>
    <item>
      <title>THE DOUBLE-WIDE DESIGN: AN INEXPENSIVE WAY TO INCREASE THE CAPACITY OF SIGNALIZED INTERSECTIONS ON FOUR-LANE HIGHWAYS</title>
      <link>https://trid.trb.org/View/755628</link>
      <description><![CDATA[Four-lane highways make up the backbone of the transportation system in many urban and suburban areas.  Signalized intersections along these highways are often over-capacity during peak hours.  Typically, agencies plan to widen these four-lane highways to six or eight lanes someday, but funding constraints and environmental concerns mean the widening will not happen anytime soon.  Agencies need temporary measures to add capacity to these highways at signalized intersections in lieu of a full-fledged widening project.  The author developed the double-wide intersection design to provide that temporary capacity increase.  The double-wide design increases the number of through lanes at the intersection from two to four in a direction, then reduces the number back to two shortly after the intersection.  The reduction is accomplished using a second signal, which has two phases and provides the right-of-way to two of the four lanes at a time, or through two two-lanes-to-one lane merges.  The compact nature of the double-wide design, reducing the cross-section back to two through lanes in each direction within 1000 ft or so of the intersection, keeps the construction costs, property acquisition costs, and environmental impacts low.  This paper summarizes work performed to date on the double-wide design.  The paper provides a thorough description of the double-wide design, and compares the design to competitors in terms of:  capacity, from Highway Capacity Manual calculations; delay and travel times, from CORSIM simulations; and construction and property acquisition costs.  The paper also discusses potential safety issues with the design and suggests future research needed to bring the design into standard practice.]]></description>
      <pubDate>Fri, 08 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755628</guid>
    </item>
    <item>
      <title>NEW INTERCHANGE AND INTERSECTION DESIGNS: THE SYNCHRONIZED SPLIT-PHASING INTERSECTION AND THE DIVERGING DIAMOND INTERCHANGE</title>
      <link>https://trid.trb.org/View/755629</link>
      <description><![CDATA[Existing intersections and interchange designs can be deficient due to the inability to accommodate common traffic patterns and due to road networks being originally engineered for a strong hierarchy of intersecting roads when currently many intersecting roads have similar characteristics.  The purpose of this paper is to introduce two new designs, developed by the author, which can accommodate the traffic patterns at major intersections and interchanges.  The intersection design is called the "synchronized-split phasing intersection."  The interchange design is called the "diverging diamond interchange."  These designs take advantage of the benefits of split-phasing and signal synchronization to theoretically improve signal timing at heavy volume intersections or heavy turning movements. Simulations were conducted to compare the delay and total stops of these new designs to other conventional designs.  The results showed that the synchronized split-phasing intersection and the diverging diamond interchange operated much more efficiently than the original designs.  There seems to be great potential for these designs, although more research would be needed to look into alterations in traffic patterns and signal spacing, as well as a cost analysis.]]></description>
      <pubDate>Fri, 08 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755629</guid>
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    <item>
      <title>TRANSPORTATION CONCERNS NEAR SCHOOLS</title>
      <link>https://trid.trb.org/View/755630</link>
      <description><![CDATA[The State of Texas, particularly in the large urban areas, has experienced considerable population growth in recent years. This growth has produced new schools in areas near highways originally designed for low volumes and relatively high speeds. Another trend is the higher proportion of children being transported to and from schools in private vehicles.  These realities, and many of the other issues associated with traffic around schools, make it important to aggressively consider the design of roadways within and around schools to ensure the safest possible traffic environment.  Equally important is the consideration of the location and design of the school site, preferably during the planning stages, in order to establish safe and efficient operations.  Observations were conducted at 14 schools to identify transportation issues in need of research.  Literature review, surveys, and reviews of existing guidelines also contributed to identifying transportation issues.  Preliminary observations at the sample of Texas schools showed the following:  at almost all sites, the average service time (i.e., the amount of time spent on-site in the main parent drop-off/pick-up zone) was significantly more variable for afternoon pick-up operations as opposed to the morning drop-off; there was a wide variety of design, operations, and traffic control/markings practices at the school sites studied; some of the schools used pro-active practices such as placement of traffic cones, use of gates and/or other barriers, and use of student and staff for on-site traffic control to improve the safety and flow of traffic within their campus; and schools that had separation of the basic traffic types appeared to have less safety conflicts than those where separation was not present.]]></description>
      <pubDate>Fri, 08 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755630</guid>
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      <title>TRAFFIC OPERATIONS AND SAFETY AT SCHOOLS: REVIEW OF EXISTING GUIDELINES</title>
      <link>https://trid.trb.org/View/755631</link>
      <description><![CDATA[A recent Texas research study used a variety of methods to obtain information on existing guidelines for transportation-related elements on school sites.  These methods included review of published documents, Internet searches, survey instruments, and direct correspondence.  The objective of the study was to develop guidelines and good examples for the design and operation of roadway facilities within and around schools in order to improve safety and reduce local congestion. Findings from the initial reviews showed:  a) Several agencies provided general site requirements and design for separation of transport modes; service, delivery, and maintenance issues; emergency access issues; weather protection; and general site design and layout; b) There was a significant number of bus-related design and operations guidelines; c) General information on parent drop-off/pick-up zone was included in several sources; however, specific guidance was limited.  South Carolina DOT had a guideline for on-site stacking length ranging from 800 to 1500 ft (244 to 458 m) depending on school type and student population; d) A number of studies and programs have been dedicated to bicycle and pedestrian issues for schools (generally under the Safe Routes to School umbrella); and e) About half of the DOT survey respondents indicated they have existing design guidelines for the number and spacing of driveways, over 70% indicated that they have existing guidelines for turn lane installation, and several indicated that they treat schools the same as other land uses in determining number and spacing of driveways and turn lanes.]]></description>
      <pubDate>Fri, 08 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755631</guid>
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      <title>THE EFFECTS OF SCHOOL ZONES ON DRIVER BEHAVIOR</title>
      <link>https://trid.trb.org/View/755632</link>
      <description><![CDATA[Current data suggest that speeding in school zones is prevalent and presents a real danger to pedestrians and especially to child pedestrians.  This paper reports on a study that collected data describing driver behavior in school zones using remote sensing technology.  This continuous speed data set helped identify driving trends adjacent to active or inactive school speed zones.  This paper includes a summary of the data collected and the results of a statistical analysis showing speed trends.  Data are analyzed according to adjacent street characteristics and school zone safety measures.  In general, the authors found that the school zone signage appeared to have no influence on driver behavior at the sites studied.]]></description>
      <pubDate>Fri, 08 Apr 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/755632</guid>
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