Study Location
The study is located at the intersection of Alden Road and O'Brien Road in McHenry County.
Project Schedule
The project schedule is shown below as it progresses from initiation in Phase I to construction in Phase III. The schedule below is subject to project readiness and funding availability.
- Phase 1 includes all tasks related to preliminary engineering and environmental studies, in pro-gress now, which will take place during the years 2024-2026. The phase 1 schedule has four stag-es. Stage 1 took place in 2024 and included gathering and analyzing existing data, used for devel-opment of the Purpose and Need, traffic and safety analysis, drainage studies, environmental surveys, and stakeholder meetings. Stage 2 takes place in 2025 and includes developing and ana-lyzing initial alternatives, used to identify concepts to address project needs, and identify oppor-tunities to minimize impacts. Public Information Meeting #1 takes place during this phase, in the Spring. Stage 3 will take place in 2025 and 2026 and includes identifying the preferred alternative. In this stage, the team uses public feedback to evaluate the initial alternatives, develops the pre-ferred alternative, and hosts Public Information Meeting #2 in Fall of 2025. In early 2026, Phase 1 of the study is completed and the design is approved.
- Phase 2 begins next, which will include land acquisition and contract plan preparation. It will take place from 2026 to 2028, pending project readiness and funding availability.
- Phase 3 includes project construction, and is expected to take place in 2028.
Purpose and Need
The Need for the project is to improve safety for all users of the intersection.
- 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 stop signs
- Failure to yield the right-of-way
- Limited sight distance
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.
| Road | Alden Road | O'Brien Road |
|---|---|---|
| Speed Limit | 55 mph | unposted |
| Jurisdiction | McHenry County | Alden Township |
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. The existing volume and predicted growth indicate that the current number of lanes accommodate the traffic demand of the area.
- 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 and predicted growth indicates that the number of lanes at the Alden Road and O'Brien Road intersection are sufficient to accommodate the traffic demand of the area.
Safety
Deficiencies documented at the intersection contribute to an increased risk of crashes, injuries, and fatalities.
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 Crash Type
By Crash Severity
- Type A: Incapacitating Injury
- Type B: Non-Incapacitating Injury
- Type C: Non-Evident Injury
- PDO: Property Damage Only
Crash Categories
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%
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 and paved shoulders
Alternatives
This section presents several transportation alternatives identified to address the project Purpose and Need.
-
Alternative 1: Existing Intersection (No Build)
Existing Conditions:
- One lane in each direction
- Substandard paved shoulder widths
- No stop bars or pavement markings on O'Brien Road
- Maintain existing two-way stop
-
Alternative 2: Centered Roundabout
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 and ditch widening
- Pedestrian and bicycle accommodations
-
Improved safety
-
Alternative 3: Off-Set Roundabout
Improvements include:
- Reduced impacts to nearby homes and trees
-
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 and ditch widening
- Pedestrian and bicycle accommodations
-
Alternative 4: Restricted Crossing U-Turn (RCUT)
Improvements include:
- Reduces likelihood for angle and left turning crashes
- Maintaining free flow traffic on Alden Road
- Depressed median and U-Turn bump outs on both sides of Alden Road
- Shoulder and ditch widening
- Pedestrian and bicycle accommodations
Alternatives Evaluation
The table below compares alternatives based on both their ability to address intersection deficiencies effectively and the potential for impacts to environmental features or adjacent properties
| Evaluation Category | Alternative 1 Existing Intersection (No Build) | Alternative 2 Centered Roundabout | Alternative 3 Off-Set Roundabout | Alternative 4 Restricted Crossing U-Turn [RCUT] |
|---|---|---|---|---|
| Crash Reduction | Negative Improvement |
Satisfactory Improvement |
Satisfactory Improvement |
Satisfactory Improvement |
| Speed Reduction | No change |
Satisfactory Improvement |
Satisfactory Improvement |
Negative Improvement |
| Intersection Visibility | No change |
Satisfactory Improvement |
Satisfactory Improvement |
Satisfactory Improvement |
| Turn Movement Improvements | Negative Improvement |
Satisfactory Improvement |
Satisfactory Improvement |
Minimal Improvement |
| Improved Shoulders | No change |
Satisfactory Improvement |
Satisfactory Improvement |
Satisfactory Improvement |
| Environmental Impacts | No change |
Minimal Improvement |
Minimal Improvement |
Negative Improvement |
| Number of Properties Impacted | No change |
4 Properties (minimal) |
4 Properties (minimal) |
14 Properties (negative) |
| Cost | No change |
Minimally Impacted Cost |
Minimally Impacted Cost |
Negatively Impacted Cost |
-
No change
-
Negative impact
-
Minimal improvement/impact
-
Satisfactory improvement/impact
Contact Us
Please visit the project website for more information.
You can contact the project team by email or mail with questions or comments.
Project Website
McHenry County Division of Transportation
Attn: Rebecca Brazas, Project Manager
16111 Nelson Road
Woodstock, IL 60098
Comments due May 7, 2025.
