USA Banner
  U.S. flag
              An official website of the United States government Here's how you knowOfficial US Government Icon
              **Official websites use .gov**A **.gov** website belongs to an official government organization in the United States.
            Secure Site Icon
              **Secure .gov websites use HTTPS**
                  A **lock** ( A locked padlock ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. 
 U.S. Department of Transportation Icon United States Department of Transportation
 Search DOT
            Search
                    About FHWAFHWA Organization
                Headquarters Offices
                Field Offices
                Strategic Plan
                Business Opportunities
                Staff Directories
                Careers
                Highway History
                Contact UsProgramsAcquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                Safety
                Browse by TopicsResourcesCore Highway Topics
                Federal Aid Essentials
                Automation
                Complete Streets
                Laws and Regulations
                Policy & Guidance Center
                Section 508
                Publications and Statistics
                Professional Development
                National Highway Institute
                Resource Center
                Accessibility Resource Library
                FHWA Research LibraryNewsroomPress Releases
                Speeches & Testimony
                Photos
                Videos
                Media ContactsMenu FHWA Highway Safety Programs Home
                        Safety
                        Other Safety Areas


            
            In This Section
        Other Safety Areas
                Road Diets
                Lighting and Visibility
                                Overview
                Sign Retroreflectivity
                Pavement Markings
                Roadway Lighting
                Focused Approach to Safety
                Motorcyclist Safety
                Older Road Users
                                Overview
                Crash Facts
                Engineering and Training
                Federal and State Programs
                Community Resources
                Articles
                Work Zone Safety
                Transportation Safety Planning (TSP)
      
   Contact Us
      Jeffrey Shaw
      
                    
            Program Contact
      
                    
            Office of Safety Programs
      
                
    **Email:**jeffrey.shaw@dot.gov
    If you are deaf, hard of hearing, or have a speech disability, please dial 7-1-1 to access telecommunications relay services.
                
                Geometric Design Key Components
    

    
    
          Access Management

Access Management seeks to improve traffic distribution, reduce vehicle conflicts, and reduce crashes, by providing better control of driveway access points. The result is a roadway that functions safely and efficiently for its useful life, and a more attractive corridor. A good access management practice can offer a great combination among operation, geometric design and safety.

General Benefits of Access Management

"By managing roadway access, government agencies can extend the life of roads and highways, increase public safety, reduce traffic congestion, and improve the appearance and quality of the built environment. Not only does access management preserve the transportation functions of roadways, it also helps preserve long-term property values and the economic viability of abutting development. From an environmental perspective, improved traffic flow translate into greater fuel efficiency and reduced vehicular emissions. Consolidating access roads is also less damaging to rural landscapes or environmentally sensitive areas that numerous individual private drives." ("Access Management Manual" - TRB, 2003)

NEW **Proven Safety Countermeasures**
	Corridor Access Management is featured as one of the nine Proven Safety Countermeasures that are the subject of the 2012 Guidance Memorandum on Promoting the Implementation of Proven Safety Countermeasures.Interactive Highway Safety Design Model (IHSDM)

IHSDM is a suite of software analysis tools for explicit, quantitative evaluation of safety and operational effects of geometric design decisions during the highway design process. It culminates a multiyear research and development effort conducted by the Federal Highway Administration.

IHSDM is intended for use throughout the highway design process from preliminary planning and engineering through detailed design to final review. It may be used both for projects to improve existing roadways and projects to construct new roadways. Intended users include highway project managers, designers, and traffic and safety reviewers in State and local highway agencies and engineering consulting firms. The 2014 release of IHSDM has six evaluation modules: (1) crash prediction, (2) policy review, (3) design consistency, (4) intersection review, (5) traffic analysis, (6) driver/vehicle. The IHSDM - HSM Predictive Method 2014 Release may be downloaded free-of-charge at http://www.ihsdm.org.

Roundabouts

A roundabout is a one-way, circular intersection in which traffic flows around a center island. To reduce crashes and improve intersection safety, FHWA recommends the use of roundabouts, where appropriate. Roundabouts are designed to meet the needs of all road users-drivers, pedestrians, pedestrians with disabilities, and bicyclists. Proper site selection and pedestrian channelization are essential to making roundabouts accessible to all users.

A roundabout eliminates some of the conflicting traffic, such as left turns, which cause crashes at traditional intersections. Because roundabout traffic enters or exits only through right turns, the occurrence of severe crashes is substantially reduced. Small angle collisions that may occur as a result of a right-hand turn are typically less severe than other types of collisions.

NEW **Proven Safety Countermeasures**
	Roundabouts are featured as one of the nine Proven Safety Countermeasures that are the subject of the 2012 Guidance Memorandum on Promoting the Implementation of Proven Safety Countermeasures.
              
      
    
          Last updated: Tuesday, May 16, 2023 U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

1200 NEW JERSEY AVENUE, SE

WASHINGTON, DC 20590

202-366-4000Subscribe to email updates
                    About
  

        
              About FHWA
                Careers
                Org Chart
                Staff Directories
                Work with UsPrograms
  

        
              Acquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                SafetyPolicies, Rights, Legal
  

        
              About DOT
                Accessibility
                Budget and Performance
                Civil Rights
                FOIA
                Information Quality
                No FEAR Act
                Office of Inspector General
                Privacy Policy
                USA.gov
                Web Policies and Notices
                Web StandardsNews & Events
  

        
              Newsroom
                Press Releases
                Speeches & Testimony
                Media Contacts
                Connect with Us