BACKGROUND
The design of driveways has benefited from little comprehensive research and no national design guidance since the American Association of State Highway Officials (AASHO) publication,
An Informational Guide for Preparing Private Driveway Regulations for Major Highways, was
published in 1959. Since that time, roadway design, function, and volumes have changed as have vehicle design and many other aspects of the roadway environment.
Driveways, especially busy commercial drives, can have a significant impact on the adjacent roadway. Good driveway design should facilitate smooth vehicle egress and ingress to and from the roadway and should also provide for pedestrians and bicyclists. Driveway design needs to account for roadway functional class or driveway usage to better accommodate varying roadway environments, community needs, and existing conditions. There is currently little guidance on this issue.
The
Draft Guidelines for Accessible Public Rights-of-Way, disseminated by the U.S. Access Board for public comment in 2001, provides specific guidelines for such elements as minimum width, cross slope, grade, curb ramps, directionality, and edge conditions at the intersection of sidewalks and driveways to comply with the Americans with Disabilities Act. These guidelines are based on pedestrian needs and do not comprehensively address safe and efficient vehicle movements near driveways. Recommendations are needed to accommodate accessibility concerns as well as safe and efficient vehicle use of the driveway.
OBJECTIVE
The objective of this research is to develop recommendations for geometric design of driveways. The recommendations will be useful to state departments of transportation and local governments in preparing driveway design standards and practices that consider standard engineering practice and accessibility needs and provide for safe and efficient travel by motorists, pedestrians, and bicyclists on the affected roadway.
The research will accomplish the objective through the following tasks.
TASKS
Phase I (1.) Conduct a review of domestic and international literature and current practice pertaining to the geometric design of driveways. Determine the current state of practice and develop a synthesis of completed and in-progress research. Submit the findings to the NCHRP panel for review. (2.) Identify the geometric elements (e.g., radius, profiles, grade, drainage controls, vehicle type) of driveway design. Develop performance measures for each geometric element as it relates to safe and efficient travel by concurrent interests (e.g., motorists, pedestrians, and bicyclists). (3.) Critically evaluate the adequacy of the current state of practice for each geometric element identified in Task 2. Identify specific elements where existing information is adequate for the development of recommendations and identify specific elements where research is needed. (4.) Propose and prioritize detailed plans for addressing each of the research needs identified in Task 3. The plans should include specific research methodologies, justification, cost, and probability of success for each need that will be addressed. (5.) Submit an interim report documenting Tasks 1 through 4 for review and approval by the NCHRP panel. The interim report will include the prioritized, detailed plans proposed in Task 4 as well as the work plan for completing Phase II of the research. Meet with the NCHRP panel to discuss the interim report and the Phase II work plan.
Phase II (6.) Conduct research in accordance with the Phase II work plan approved by the panel during the Task 5 interim meeting. Based on the results of this research and existing information determined to be adequate in Task 3, develop recommendations for the geometric design of driveways. (7.) Submit a final report documenting the entire research effort.
Status: The final report has been published as NCHRP Report 659.
Product Availability: NCHRP Report 659: Guide for the Geometric Design of Driveways and the Contractor's Final Report NCHRP Web-Only Document 151: Geometric Design of Driveways are available.
