Safety Initiative McHenry County Alden Road at O'Brien Road

Project Location

The study is located at the intersection of Alden Road and O’Brien Road in McHenry County.

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Project Schedule

The study is located at the intersection of Alden Road and O’Brien Road in McHenry County.

Phase 1

Preliminary engineering & environmental studies in progress

2024 - 2027

Phase 2

Land Aquisition & Contract Plan Preparation

2027 - 2028*

Phase 3

Project Construction

2029*

*Pending project readiness and funding availability

Phase 1 Schedule

2024

Gathering & Analyzing Existing Data

• Purpose and Need
• Traffic and Safety Analysis
• Drainage Studies
• Environmental Surveys
• Stakeholder Meeting

2025

Develop & Analyze Initial Alternatives

• Identify concepts to address project needs
• Identify opportunities to minimize impacts
• Public Information Meeting #1 April 16, 2025

2025 - 2026

We Are Here

Identify Preferred Alternative

• Use public feedback to evaluate the initial alternatives
• Develop preferred alternative
• Public Information Meeting #2, presenting preferred alternative. October 21, 2026

2027

Completion of Phase 1 / Design Approval

Purpose and Need

The Purpose of the project is to improve safety for all users of the intersection.

The Need for the project includes addressing the geometric deficiencies of the Alden Road at O’Brien Road intersection due to the history of crashes, which includes angle crashes, that were a result of:

Disregarding traffic control devices

Failure to yield the right-of-way

Seasonal limited sight distance

Speeds of vehicles approaching the intersection

Existing Conditions

Alden Road at O'Brien Road is a rural intersection controlled by stop signs in each direction on O'Brien Road only. Both roads have a single travel lane in each direction with minimal paved shoulders.

Average Daily Traffic (ADT) Flow

Traffic counts were performed during 24 hours on a weekday in 2023 to collect existing traffic volumes.

The Chicago Metropolitan Agency for Planning (CMAP) provides 2050 traffic volumes based on anticipated land use changes in the region.

• Alden Road southbound: 2650 traffic volume currently; 3600 future traffic volume
• Alden Road northbound: 2550 traffic volume currently; 3500 future traffic volume
• O'Brien Road eastbound: 950 traffic volume currently; 1250 future traffic volume
• O'Brien Road westbound: 800 traffic volume currently; 1050 future traffic volume

Legend

• X,XXX Existing 2023 ADT
• (X,XXX) Future 2050 ADT

The existing volume and predicted growth indicate that the current number of lanes accommodate the existing and projected future traffic demand.

Safety

Crash History (2019-2023)

• 9 Crashes
• 8 Injuries
  • 6 Angle
  • 2 Fixed Object Avoiding a Vehicle
• 2 Serious Injuries
  • 2 Fixed Object Avoiding a Vehicle
• 1 Fatalities
  • 1 Angle

By Potential Crash Cause*

• Failing to Yield Right-of-Way 78%
• Disregarding Stop Sign 43%
• Failing to Reduce Speed to Avoid Crash 10%
• Driving Skills / Knowledge / Experience 10%

• 0%
• 20%
• 40%
• 60%
• 80%
• 100%

*Each crash may have up to two potential causes identified.

4 crashes occurred in 2024 – 2025

By Crash Type

By Crash Severity

Crash Categories

• Type A: Incapacitating Injury
• Type B: Non-Incapacitating Injury
• Type C: Non-Evident Injury
• PDO: Property Damage Only

Deficiencies or problems contributing to crashes:

• Disregarding traffic control devices or failing to yield right-of-way to oncoming traffic
  • Misconception that intersection is an all-way stop
  • Limited sight distance during growing season
• Posted speed limit increases for traffic on southbound Alden Road approaching the intersection
• Lack of painted stop bar, paved shoulders and minimal shoulder width

Preferred Alternative Roundabout

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Improvements Include:

• Improved safety
  • 90% reduction in fatal crashes
  • 83% reduction in angle crashes
  • 75% reduction in injury crashes
    Federal Highway Administration, FHWA
• Reduced conflict points
• Slower speeds through the intersection
• Shoulder & ditch widening
• Intersection lighting
• No wetland impacts

Drainage

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Improvements Include:

• Proposed design mimics existing drainage patterns and outlets
• Culverts sized for modern rainfall amounts
• Ditch slopes improved to minimize standing stormwater
• Storm sewer to drain roundabout pavement

Planned Detour Routes

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What We’ve Heard

Contact Us

Please visit the project website for more information.

You can contact the project team by email or mail with questions or comments.