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FHWA Home / Safety / Proven Safety Countermeasures / Corridor Access Management

Corridor Access Management

Access management refers to the design, application, and control of entry and exit points along a roadway. This includes intersections with other roads and driveways that serve adjacent properties. Thoughtful access management along a corridor can simultaneously enhance safety for all modes, facilitate walking and biking, and reduce trip delay and congestion.

Illustration: This schematic shows a signalized intersection with adjacent corridor access points. The mainline of the corridor runs left to right. At the signalized intersection, the northeast and southwest corners are labeled mainline approach corner, while the northwest and southeast corners are labeled mainline receiving corner. The access point located adjacent to the southwest mainline approach corner is closer to the intersection than the others. This access point falls short of the minimum corner clearance distance indicated between the signalized intersection and the access point.

Schematic of an intersection and adjacent access points. Source: FHWA

Every intersection, from a signalized intersection to an unpaved driveway, has the potential for conflicts between vehicles, pedestrians, and bicyclists. The number and types of conflict points—locations where the travel paths of two users intersect—influence the safety performance of the intersection or driveway. FHWA developed corridor-level crash prediction models to estimate and analyze the safety effects of selected access management techniques for different area types, land uses, roadway variables, and traffic volumes.1

The following access management strategies can be used individually or in combination with one another:

  • Reduce density through driveway closure, consolidation, or relocation.
  • Manage spacing of intersection and access points.
  • Limit allowable movements at driveways (such as right-in/right-out only).
  • Place driveways on an intersection approach corner rather than a receiving corner, which is expected to have fewer total crashes.2
  • Implement raised medians that preclude across-roadway movements.
  • Utilize designs such as roundabouts or reduced left-turn conflicts (such as restricted crossing U-turn, median U-turns, etc.).
  • Provide turn lanes (i.e., left-only, right-only, or interior two-way left).
  • Use lower speed one-way or two-way off-arterial circulation roads.

Successful corridor access management involves balancing overall safety and mobility for all users along with the needs of adjacent land uses.

Illustration: : This illustration shows two adjacent single lane roundabouts. Each roundabout has four approaches. On the roadway segment between the two roundabouts, a driveway is present. A continuous, raised median runs along this roadway segment, restricting movements in and out of the driveway and reducing conflicts.

Tandem roundabouts with a continuous raised median eliminates left-turn and across-roadway conflicts. Source: FHWA

Sources

1. Gross et al. Safety Evaluation of Access Management Policies and Techniques. FHWA-HRT-14-057, (2018).

2. Le et al. Safety Evaluation of Corner Clearance at Signalized Intersections. FHWA-HRT-17-084, (2018).

3. Harwood et al. Prediction of the Expected Safety Performance of Rural Two-Lane Highways. FHWA-RD-99-207, (2000).

4. Elvik, R. and Vaa, T., Handbook of Road Safety Measures. Oxford, United Kingdom, Elsevier, (2004).

Safety Benefits:

Reducing driveway density

5-23%

reduction in total crashes along 2-lane rural roads.3

25-31%

reduction in fatal and injury crashes along urban/suburban arterials.4

 


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Page last modified on October 28, 2021
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