Evaluating the Application of Diverging Diamond Interchange in Athens, Alabama

Khan, Tahmina; Anderson, Michael

doi:10.7708/ijtte.2016.6(1).04

Cited by 17 publications

(14 citation statements)

References 5 publications

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“…No real-world field analysis was possible to be conducted for the new ODI design, as it is a proposed design which has not been built anywhere yet. Therefore, similar to past studies, simulation models were used to evaluate traffic operation of the new design ( 1, 3–5, 9–15, 17, 18 ). Synchro and VISSIM were selected for the simulation modeling, as they are popular simulation tools in the U.S.A. Synchro is a macroscopic simulation tool for modeling traffic signals at intersections based in part on the Highway Capacity Manual ( 20 ).…”

Section: Methodsmentioning

confidence: 99%

“…Conventional diamond interchanges should be the preferred design at interchanges with low left-turning conditions (lower than 30% of the whole traffic volume), while the DDI is more likely to provide superior performance to a diamond when the left-turn traffic ratio exceeds 50% of the total left and through-traffic demand ( 13 ). Another study did not find any significant benefit in upgrading a conventional diamond interchange to a DDI in a case study in Alabama ( 14 ). Also, providing a two-way progression system for through-traffic demand in a DDI is difficult, and the DDI’s simultaneous progression system wastes a portion of the progression bandwidth because of the vehicle travel time between traffic signals ( 15 ).…”

mentioning

confidence: 98%

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Improving Traffic Operations at Service Interchanges using the New Offset Diamond Design

Molan

Hummer²

2020

Transportation Research Record: Journal of the Transportation R

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This paper proposes the new offset diamond interchange (ODI) as an alternative design which shows potential in mitigating the limitations of failing service interchanges in relation to traffic operation. Vehicle travel time was considered as the primary measure of effectiveness (MOE) for the traffic operation analysis, while the maximum queue lengths were also analyzed. A comprehensive series of VISSIM simulation scenarios was conducted to evaluate the new ODI design in different situations of traffic demand, turning-traffic ratios, traffic distribution, and traffic composition. The results were compared with five existing and four other new interchange designs. The new ODI performed statistically significantly better than all existing designs, including the conventional diamond, parclo A, and the diverging diamond interchange (DDI). The ODI design was found vulnerable in relation to the maximum queue produced in high turning conditions with the unbalanced traffic distribution; however, the threat could be diminished by increasing the storage lengths about 80 ft. Right-of-way (ROW) costs may make the ODI a poor alternative in replacing a standard diamond, but since the ODI fits the footprint of a parclo A it could work well in replacing those interchanges.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 98%

Improving Traffic Operations at Service Interchanges using the New Offset Diamond Design

Molan

Hummer²

2020

Transportation Research Record: Journal of the Transportation R

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“…Typical safety benefits of a DDI include: reducing conflict points from 26 for a conventional diamond to 14, spreading out conflict points throughout the interchange, maintaining better sight distance at turns, reducing the opportunity for wrong way entries to ramps, and shortening pedestrian crossings. Operational benefits include unique phase combinations, "Free" or simple left and right turns from all directions, increased left turn lane capacity without needing more lanes, only needing two phases, shorter cycle length, lanes with multiple assignments in all directions, better storage between the ramp terminals, improved U-turn maneuvers from the freeway, and better signal network synchronization compared to a CDI [2].…”

Section: Introductionmentioning

confidence: 99%

Framework for Considering a Diverging Diamond Interchange to Improve Operations and Safety

Diaz¹,

Rios²,

Medina³

et al. 2019

Proceedings of the 17th LACCEI International Multi-Conference for Engineering, Education, and Technology: “Industry, Innovation

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Innovations on intersection design have been the focus of recent developments in the US and around the world. The second installment of the Every Day Counts initiative (EDC-2) from the Federal Highway Administration (FHWA) promoted five new intersection designs. One of them was the Diverging Diamond Interchange (DDI). This innovative design has been implemented in several cities in the US to improve operations and safety. Puerto Rico is currently building its first DDI in the intersection of an arterial street and a freeway in the Municipality of Gurabo. This paper discusses the main characteristics of the DDI and presents a design framework from conception to implementation. This framework considers the geometric, environmental, and cultural influence in the design of a DDI, while also paying attention to the influence of non-motorized users and the continuous evaluation of the intersection by using driving simulation as part of the effective project implementation. Other topics discussed include safety evaluation, signaling, traffic influence, and the use of driving simulation into the determination of operational safety at a DDI. Also, the comparison between the conventional diamond interchange and the DDI, potential DDI issues from an operational point of view, and the objectives or goals of this type of intersection design are presented. A discussion of the benefits of using a driving simulator as a tool to evaluate a DDI and the importance of the data gathered in the process are also explained. Details of the implementation of this framework in Puerto Rico are presented as concluding remarks.

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“…On the other hand, the previous studies mentioned a lack of capacity in the DDI, especially in high through traffic conditions. As an example, a DDI was not a proper treatment for improving a conventional diamond interchange for a case in Alabama ( 25 ). Regarding the pedestrian performance, two different paths have been used at a DDI: (1) a center crossing, and (2) an outside crossing.…”

Section: Introductionmentioning

confidence: 99%

Simulation Modeling of Pedestrian Performance in the New Synchronized and Milwaukee B Interchanges versus Existing Designs

Molan

Hummer²

2018

Transportation Research Record

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Most U.S. highway agencies recognize the importance of designing safe, short, and comfortable paths for pedestrians. Providing such an acceptable condition for pedestrians requires specific attention at intersections and service interchanges due to their interaction with other modes of transportation. The main objective of this research was to analyze pedestrian operation at two new service interchanges—the synchronized and Milwaukee B interchanges—in comparison with four existing designs. The analysis consists of three main parts: (1) a general comparison among the designs for pedestrian performances in terms of safety, travel time, and the level of service; (2) investigation of the effects of vehicles on pedestrian performance; and (3) modeling the impact of pedestrians on the traffic operation of vehicles. A comprehensive series of simulation tests were run using VISSIM and Synchro to study the pedestrian performance of interchanges in various situations of traffic volume, turning traffic ratio, traffic distribution, and percentage of heavy vehicles. The results indicated that a relatively safe condition is expected for pedestrians in the proposed new designs in comparison with the existing interchanges; however, the pedestrians’ travel time was lower in all the existing designs than in the new designs except the diverging diamond interchange (DDI). The DDI, one of the most popular alternative interchanges, showed the worst performance in all the aspects of the pedestrian analysis. Despite the very good performance of conventional diamond interchange regarding pedestrian travel time and safety, pedestrians could have a significant negative impact on vehicle travel time through a diamond.

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Evaluating the Application of Diverging Diamond Interchange in Athens, Alabama

Cited by 17 publications

References 5 publications

Improving Traffic Operations at Service Interchanges using the New Offset Diamond Design

Improving Traffic Operations at Service Interchanges using the New Offset Diamond Design

Framework for Considering a Diverging Diamond Interchange to Improve Operations and Safety

Simulation Modeling of Pedestrian Performance in the New Synchronized and Milwaukee B Interchanges versus Existing Designs

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