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Development of a Crashworthy Tangent End Treatment for Low-Speed and Curbed Roadways

项目名称：	Development of a Crashworthy Tangent End Treatment for Low-Speed and Curbed Roadways
摘要：	As part of making our transportation system more multimodal, state departments of transportation (DOTs) and other transportation agencies are seeking new design solutions to address mobility and safety for all users in low-speed urban and suburban environments. These environments often feature trees, poles, landscaping, medians, shared paths, and other design elements to improve livability and support increased walking and cycling. Where roadside safety barriers are desired in low-speed environments, low-profile barriers designed to address crash risks at lower speed conditions (MASH TL-2) are often favored because they are more compatible with the community context. Yet the space available for crashworthy end treatments for these barriers can be highly constrained in many urban and suburban locations because of closely spaced intersections and driveways, limited right-of-way, and the presence of street trees and other features. In addition, the presence of vertical curbs and adjacent sidewalks or multiuse paths restrict the use of a flared end treatment. Rural locations can have similar constraints and conditions, even without the presence of a curb. To balance the needs of all users, community priorities, and location constraints, a viable crashworthy end treatment for barriers in urban and suburban roadside environments needs to minimize: (1) Length: short end treatments can be installed along roadways with longitudinal constraints including discontinuities for intersections, driveways, and crossings; (2) Width: a narrow cross-section can reduce encroachment into vehicle travel lanes and adjacent pedestrian and multiuse paths; and (3) Height: a shorter profile reduces impacts on sight distance and allows the end treatment to be used with low-profile barriers, guardrails, and typical concrete barriers/bridge traffic railings shapes. To be feasible for implementation, an end treatment must also be cost effective to install and maintain, for new installations and retrofitting existing barriers. Research is needed to provide roadside safety design practitioners with a nonproprietary, crashworthy tangent end treatment for rigid barrier systems on low-speed roadways. The objective of the research is to develop a nonproprietary, crashworthy tangent end treatment with the following characteristics: (1) appropriate for urban and suburban environments; (2) of minimal required length, width, and height; (3) can be transitioned to commonly used rigid barriers (e.g., TL-2 low profile or TL-3 concrete barriers); and (4) can be placed on top of a 6” curb or placed where there is no curb in advance of the barrier.
状态：	Proposed
资金：	750000
资助组织：	National Cooperative Highway Research Program；American Association of State Highway and Transportation Officials (AASHTO)；Federal Highway Administration
项目负责人：	Hartell, Ann M
开始时间：	20221004
主题领域：	Design；Highways；Safety and Human Factors