US Highway 16 Corridor Study – Public Meeting #3

Virtual Public Information Meeting and Open House

Welcome to our US16 Corridor Study virtual engagement! The South Dakota Department of Transportation (SDDOT) in conjunction with the Rapid City Area Metropolitan Planning Organization (RCAMPO), City of Rapid City, Pennington County, and the Federal Highway Administration (FHWA) are leading a study to develop a long range-plan for the US16 corridor. Thank you for your participation in our online engagement.

The range of transportation improvement scenarios throughout US16 presented here are ready for public and stakeholder feedback. These scenarios group refined concepts presented at the previous public meeting and represent potential future projects to address long-term transportation needs.

Consultant recommendations of the technically feasible option have also been developed for the US16/Neck Yoke Road intersections and US16/US16B/Catron Boulevard intersections, for your review and feedback. We appreciate your input.

How to Navigate

• Click the arrows on the right of your screen to go forward or the left to go backward. Use the navigation bar on the left side of your screen to revisit any part of the meeting.

Presentation Overview Video

Project Area Map

Click on a segment label to learn more about the scenarios and analysis for each.

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Segment Overview

Purpose and Need

The project team shared the preliminary purpose and need statements at the previous public meetings and solicited your input. Preliminary build options for each intersection have been developed to satisfy the identified project needs.

Purpose:

To improve traffic operations and safety at the US16/US16B/Catron Boulevard intersection, and with the goal of supporting the planned mix use urban development that is occurring in the area.

Needs:

Poor traffic operations. The existing intersection is functioning at a level of service (LOS) D for AM and LOS E for PM peak hour traffic. Future 2045 traffic operations are expected to worsen to LOS F. LOS C or above is considered acceptable congestion and traffic operation.

High crash rates. High speed and increased traffic volumes contribute to high crash rates. The high speed contributes to fixed object crashes, merge area crashes, and disregard signal crashes. Of the 88 total crashes, 48 were angle and 32 were rear end.

Rapidly urbanizing land use. The area around the intersection is currently undergoing a transition from rural to urban uses. The Rapid City Comprehensive Plan identifies the area around the intersection as a community activity center. As urbanization continues, the number of vehicle trips to and from the new urban uses will continue to increase.

Intersection Build Options – Download PDF – SPI animation – DLT animation

SPI 1.1a: SPI with Separated, Free NB and SB Right Turn Lanes

SPI 1.1b: SPI with Separated, Free NB and SB Right Turn lanes and EB Right Turn lane at Healing Way

SPI 1.2: SPI with Signalized NB and SB Dual Right Turn Lanes and EB Right Turn Lane at Healing Way

DLT 2.1a: DLT with Separated, Free NB and SB Right Turn Lanes

DLT 2.1b: DLT with Separated, Free Right Turn Lanes at Main Intersection (all Quadrants)

DLT 2.2a: DLT with Signalized Right Turn Lanes at Main Intersection (all Quadrants)

DLT 2.2b: DLT with NB and SB Signalized Right Turn Lanes, Free EB and WB Right Turn Lanes

DLT 2.3: DLT with Unseparated, Signalized Right Turn Lanes at Main Intersection

Single Point Interchange (SPI) Key Features

View an SPI animation

• Grade-separated interchange
• US16 over US16B/Catron Boulevard
• ‘Uninterrupted’ flow on US16
• Signalized intersection on US16B/Catron Boulevard (below US16)
• Provides greatest separation from Les Hollers Way and Healing Way
• US16 intersections with Tucker Street and Addison Avenue closed
• Primary differences center on treatment of NB and SB US16 right turn lanes at the single point intersection

Displaced Left Turn (DLT) Intersection Key Features

View a DLT animation

• At-grade, signalized intersection
• US16B/Catron Boulevard left turns occur at upstream crossover intersection
• This is a benefit to main intersection signal timing and overall operations
• ‘Interrupted’ flow on US16
• US16 north/south traffic may need to stop at traffic signal
• Provides least separation from Les Hollers Way and Healing Way
• Primary differences center on treatment of DLT main intersection right turn lanes

Signing Plans – Download PDF

Conceptual signing plans were developed for both an SPI and DLT intersection Build Option to help assess the ability to sign and potential driver expectancy issues, particularly for tourists who may be unfamiliar to the area.

SPI: US16B/Catron Boulevard signalized intersection spacing allows for guide signage placement between signalized intersections (i.e. Les Hollers Way and Healing Way). This location is in advance of the SPI queues to provide ample maneuver distance in response to the signage.

DLT: closely spaced intersections along US16B/Catron Boulevard requires guide signs to either be placed with little advance notification of a required turn at the DLT crossover intersections or located at least one signalized intersection prior. This may create issues with queue blockages extending through the area where guide signage is located, necessitating lane change maneuvers well upstream of the guide sign location.

Environmental Considerations

US16/16B/Catron Boulevard Intersection

Water Resources:

• No wetlands, streams, or floodplains are present

Socioeconomic:

• Future land use designated as mixed use commercial with several employers
• US 16 is considered an Entrance Corridor for Rapid City
• Bicycle and pedestrian accommodations are being coordinated with Rapid City Area MPO planning efforts
• No environmental justice populations present

Cultural Resources:

• Three historic-age properties need to be evaluated for NRHP eligibility

Hazardous Materials:

• Active underground storage tank (UST) site (Holiday Gas Station)

Noise:

• One area with measured noise above 66 dBA (see map)

Evaluation Matrix Summary

Each concept was evaluated on how they compare with other concepts in a given category and/or whether they meet study goals. This evaluation is summarized through the following color coding in the evaluation matrix.

Evaluation and Screening Process Summary – Download PDF

3-Step Process:

1. Intersection type: SPI Build Options vs. DLT Build Options
2. Sub-option review to determine if any can be screened out
3. US16 northbound/southbound right turn treatment at US16B/Catron Boulevard

• Result: Consultant Recommendation. Technical recommendation of Build Option to carry forward into the NEPA process (environmental study).

Overview:

Overview

Step 1:

Safety

Safety

Safety

Intersection Operations

Corridor Travel Time

Intersection Impacts

Intersection Impacts

US16 Access

US16 Access

Bicylce/ Pedestrian Considerations

Maintenance and Operations

Cost-Benefit Analysis

Conclusions

Step 2:

Sub-Option Review

Step 3:

Right Turn Lane Treatment

Consultant Recommendation of Technically Feasible Option – Download PDF

Recommendation

The recommended technically feasible option that best meets the established transportation needs of the US16/US16B/Catron Boulevard intersection is Build Option 1.1a, SPI with separated, free northbound and southbound right turn lanes.

Due to the operational benefits afforded to US16 northbound/southbound right turning traffic towards the end of the Planning Horizon, it is also recommended that pavement for dual right turn lanes shown in SPI 1.2 be incorporated into SPI 1.1a for an easy transition to signalized, dual right turn lanes when needed to meet intersection operational goals.

Key Benefits

• Greatest expected reduction in crashes (33% fatal and injury; 26% total).
• Lowest overall interchange/intersection delay (LOS B).
• Greatest available capacity to accommodate traffic growth and fluctuations within interchange/intersection.
• Shortest travel time along US16 and US16B/Catron Blvd corridors.
• Greatest separation between US16 and next adjacent US16B/Catron Blvd signalized intersections.
• Best addresses US16B/Catron Blvd weave concerns without degrading overall intersection/interchange operations.
• Public and stakeholder support for long-tern traffic operations and safety benefits.
• Familiarity: driver expectancy, construction, maintenance, and operation.
• BCA ratio greater than 1.0 showing that benefits are expected to exceed costs.

SPI Build Options Not Carried Forward Summary Table

DLT Build Options Not Carried Forward Summary Table

Segment Overview

US16 urban area is applies to the US16 corridor, starting south of the Moon Meadows Drive intersection and extending to the Cathedral Drive/Fairmont Boulevard intersection in Rapid City. Scenarios presented for this segment incorporate the Consultant Recommendation of an SPI at the US16/US16B/Catron Boulevard intersection (planned Fiscal Year 2026 project, identified in 2025-2028 developmental Statewide Transportation Improvement Program (STIP)).

The SDDOT has also identified a US16 corridor project extending north from US16B/Catron Boulevard in their 2025-2028 developmental STIP. A goal of this study is to determine what improvements are needed as part of the planned developmental STIP projects and what reflect a longer-range vision of future projects within the 2050 Planning Horizon.

In addition to the planned US16/US16B/Catron Boulevard intersection planned for Fiscal Year 2026, the SDDOT has also identified a US16 corridor project extending north of US16B/Catron Boulevard. One goal of this study is to identify corridor and intersection improvements:

1. Incorporated with the US16/US16B/Catron Boulevard intersection project,
2. Incorporated with the programmed US16 corridor project to the north, or
3. Are part of a longer-range vision of improvements for future projects within the 2050 Planning Horizon.

Corridor Scenarios – Download PDF

Typical Section Options

• Suburban section throughout corridor
• Urban section at intersections or areas with limited ROW
• 40’ raised median typical
• 12’ to 28’ raised median on grade south of Cathedral Drive
• Shared-use path on east side
• Sidewalk on west side

US16 Corridor Scenario 1: 4-Lane Divided (Shifted East) with Intersection Improvements

• Shifted east alignment
• Fort Hays access: ¾, right-in right-out (RIRO), or closure options with rearage connection
• Moon Meadows Drive intersection: full access (signalize when warranted)
• Section Line Road access: RIRO + NB left turn, RIRO, closure, or overpass options
• Promise Road intersection: full access shifted north (signalize when warranted)
• Tablerock Road access: ¾ access shifted north
• Enchantment Road intersection: full access shifted north to Highwood Road (signalize when warranted)
• Tower Road access: ¾, RIRO, or closure options with connection to Enchantment Road

US16 Corridor Scenario 2: 4-Lane Divided (Shifted East) with Alternative Intersection Improvements

• Shifted east alignment
• Fort Hays access: right-in right-out (RIRO) or closure options with rearage connection
• Moon Meadows Drive intersection: full access alternative intersections (signalize when warranted)
• Reduced conflict intersection (RCI)
• Median U-turn (MUT)
• Section Line Road access: RIRO + NB left turn, RIRO, closure, or overpass options
• Promise Road intersection: RCI (signalize when warranted)
• Tablerock Road access: ¾ access shifted north
• Enchantment Road intersection: RCI (signalize when warranted)
• Tower Road access: RIRO or closure options with connection to Enchantment Road

US16 Corridor Scenarios 1 and 2: 4-Lane Divided with Intersection Improvements

• Alignment centered to minimize slope cut/fill impacts
• Echo Ridge access: maintain ¾ access
• Tie into 2015 project south of Cathedral Drive

US16/US16B/Catron Boulevard Corridor Scenario 1: Wellington Drive Intersections

• Wellington Drive (west): RIRO as part of SPI layout
• Wellington Drive (east): full or ¾ access options

Major Intersections

This section summarizes evaluation measures, benefits, and drawbacks of each option at the major intersections along the US16 corridor.

US16/Moon Meadows Drive Intersection

Signalized Intersection Benefits:

• 7% predicted reduction in F&I crashes
• All movements provided at main intersection
• Driver familiarity
• Intersection queue storage areas on flat grade
• Highest B/C ratio (1.39)

Signalized Intersection Drawbacks:

• Greater US16 mainline delay and average number of stops for northbound/southbound through movements at signal

Signalized RCI Benefits:

• 17% predicted reduction in F&I crashes
• Better overall intersection operations compared to signalized intersection
• Lower US16 mainline delay and fewer stops for NB/SB through movements at signals
• Direct US16 left turns to Moon Meadows Drive
• B/C ratio greater than 1 (1.27)

Signalized RCI Drawbacks:

• Out of the way travel for EB/WB Moon Meadows Drive thru and left turn movements
• Higher cost due to additional pavement and signals
• 3% grade through south U-turn

Signalized MUT Benefits:

• 24% predicted reduction in F&I crashes
• Better overall intersection operations compared to signalized intersection
• Lower US16 mainline delay and fewer stops for NB/SB through movements at signals
• EB/WB Moon Meadows Drive thru movements at main intersection
• B/C ratio greater than 1 (1.28)

Signalized MUT Drawbacks:

• Out of the way travel for inbound/outbound Moon Meadows Drive left turn movements (predominant Moon Meadows Drive movements through 2050 Planning Horizon)
• Higher cost due to additional pavement and signals
• 3% grade through south U-turn

US16/Section Line Road Intersection

Overpass (closed) Benefits:

• Best ‘intersection’ safety performance
• All traffic routed to major intersections

Overpass (closed) Drawbacks:

• High cost
• May require some out of the way travel for US16 access until local network built out

RIRO Benefits:

• Minimal cost for local network improvements with project
• 78% reduction in predicted crashes compared to full access intersection; greatest safety benefits of at-grade intersection options

RIRO Drawbacks:

• Conflict points on US16, but no cross-traffic angle crash conflicts that have a propensity for higher severity

RIRO + NB Left Turn Benefits:

• Minimal cost for local network improvements with project
• 69% reduction in predicted crashes compared to full access intersection

RIRO + NB Left Turn Drawbacks:

• Includes NB LT cross-traffic angle crash conflict, which is a crash type that has a propensity for higher injury severity

US16/Promise Road Intersection

Signalized Intersection Benefits:

• 37% predicted reduction in F&I crashes
• All movements provided at main intersection
• Driver familiarity
• Provides greatest separation between SPI ramps and first conflict point
• No intersection functional area overlap with SPI ramps
• B/C ratio greater than 1 (1.67)

Signalized Intersection Drawbacks:

• Greater US16 mainline delay and average number of stops for NB/SB US16 through movements at signal

Unsignalized RCI Benefits:

• 84% predicted reduction in F&I crashes
• Best overall intersection traffic operations (LOS A)
• Zero US16 mainline delay due to unsignalized (free) movements
• Highest B/C ratio (2.22)

Unsignalized RCI Drawbacks:

• Due to SB U-turn sight distance constraints with NB SPI entrance ramp, southern U-turn not incorporated in intersection option

Signalized RCI Benefits:

• 52% (estimated) predicted reduction in F&I crashes
• Slightly less US16 mainline delay than traditional signalized intersection
• B/C ratio greater than 1 (1.49)

Signalized RCI Drawbacks:

• Higher cost due to additional pavement and signals
• Due to the signalized southern U-turn intersection functional area overlap into the NB SPI entrance ramp, southern U-turn not incorporated in intersection option

US16/Enchantment Road Intersection

Signalized Intersection Benefits:

• 21% predicted reduction in F&I crashes
• Improves traffic operations when volumes exhibit a need for signalization
• Driver familiarity
• Easy transition from TWSC to signalized intersection

Signalized Intersection Drawbacks:

• Greater US16 mainline delay and average number of stops for NB/SB US16 through movements at signal
• Signal not shown to be warranted until end of 2050 Planning Horizon

TWSC Intersection Benefits:

• 33% (estimated) predicted reduction in F&I crashes
• TWSC may suffice for several years before signal is warranted
• Driver familiarity
• Zero US16 mainline delay due to unsignalized (free) movements
• Easy conversion to signalized intersection

TWSC Intersection Drawbacks:

• Median must be wide enough for 2-stage crossing. Single-stage crossing results in overall intersection LOS F
• LOF F delay on side streets during 2050 peak hours

Unsignalized RCI Benefits:

• 82% predicted reduction in F&I crashes
• Best overall intersection traffic operations (LOS A)
• Zero US16 mainline delay due to unsignalized (free) movements
• Convert to signalized RCI when warranted
• Highest B-C ratio (0.88)

US16 Corridor

This section summarizes corridor-wide evaluation measures and considerations reflected in the corridor scenarios.

US16 alignment notes:

Shifted east alignment (within existing ROW) best met goals for the urban US16 corridor by providing the following benefits:

• Provides greater separation with US16 service road
• Improved constructability with work area being separate from existing lanes
• Maintains traffic on existing roadway during construction of new lanes off alignment
• Fewer utility impacts – existing utilities primarily located on west side

US16 service road notes:

Benefits to maintaining US16 service road and incorporating improved connectivity in corridor scenarios include:

• Maintains existing access to parcels and minimizes costs associated with relocating existing parcel access to other roadways.
• Minimizes construction (cost) of new frontage/local network roadways to replace gaps if service road removed.
• Maintains local network connectivity to the benefit of US16 corridor operations and safety.
• Gaps in service road connectivity would require short trips on US16, which in turn increases US16 turning movements at the expense of intersection operations and safety.

Local Roadway Network

The US16 Urban Area Local Network figure builds upon the Rapid City Major Streets Plan to incorporate the Consultant Recommendation of an SPI at US16/US16B/Catron Boulevard. This figure represents a long-range access and local network connectivity plan for the US16 urban area surrounding the US16/US16B/Catron Boulevard intersection.

Relationship of US16/US16B/Catron Boulevard Intersection Consultant Recommendations with US16 Urban Area Scenarios – Download PDF

Single Point Interchange (SPI):

Layout reflecting Consultant Recommendations and considerations for the planned US16/US16B/Catron Boulevard intersection project. See the US16/US16B/Catron Boulevard intersection sub-area section for more discussion on the Consultant Recommendation of SPI 1.1a.

Potential transition sections between SPI project limits and existing US16 roadway.

Segment Overview

Purpose and Need

The project team shared the preliminary purpose and need statements at the previous public meetings and solicited your input. Preliminary build options for each intersection have been developed to satisfy the identified project needs.

Purpose:

To improve safety and access management in the area of Neck Yoke Road.

Needs:

High crash rate. This intersection has a weighted crash rate that is in the top 5 along US 16. The severity of crashes includes one fatality and two incapacitating crashes in the past five years. It experiences a diverse range of vehicle types and driver familiarity as it provides access to several tourist destinations and also services rural residences and a school.

Multiple access points. Neck Yoke Road is the southern-most access in a series of four access points to US 16. An increased number of access point introduces opportunities for additional conflict points between vehicles and can lead to an increase in crashes, depending on the traffic control and geometrics of the access points.

Finalist Intersection Build Options – Download PDF

Layouts of all options considered can be found at the bottom of this page.

1.1c: RCI at Neck Yoke Road plus Northern Partial Access

• Similar layout to 1.1b
• Lone difference is omission of EB to WB U-turn at the northern partial access to reduce number of conflict points

1.1d: RCI at Neck Yoke Road (West)

• RCI at Neck Yoke Road intersection, shifted 250 feet west
• All area access points consolidated to main RCI
• New frontage road on west side of US16

1.1e: RCI at Neck Yoke Road (West) plus Central Partial Access (2 options)

• Similar layout to 1.1e
• Adds partial access at central Reptile Gardens/US16 service road intersection
• Option with and without frontage road on west side of US16

Conceptual Signing Plans – Download PDF

1.1c: RCI at Neck Yoke Road plus Northern Partial Access

1.1d: RCI at Neck Yoke Road (West)

1.1e: RCI at Neck Yoke Road (West) plus Central Partial Access (Option 1)

1.1e: RCI at Neck Yoke Road (West) plus Central Partial Access (Option 2)

Environmental Considerations

US16/Neck Yoke Road Intersection

Water Resources:

• Wetlands and 100-year floodplains along Spring Creek are present

Wildlife:

• Habitat surrounds intersection area
• Deer using bridge at Spring Creek to cross under US 16

Hazardous Materials:

• Active underground storage tank (UST) site (Happy Holiday RV Resort)

Cultural Resources:

• Four historic-age properties need to be evaluated for National Register of Historic Places (NRHP) eligibility
• Archaeology surveys to be completed for previously undisturbed areas, especially along Spring Creek

Noise:

• Three areas with measured noise above 66 dBA (see map)

Evaluation Matrix Summary

Each concept was evaluated on how they compare with other concepts in a given category and/or whether they meet study goals. This evaluation is summarized through the following color coding in the evaluation matrix.

Evaluation and Screening Process Summary – Download PDF

1. Intersection type: RCI vs. signalized intersection
2. Main intersection location: Neck Yoke Road vs. central driveway
3. Number of access points: one main intersection vs. one main intersection plus a partial northern access

• Result: Consultant Recommendation. Technical recommendation of Build Option to carry forward into the NEPA process (environmental study).

Overview:

Overview

Step 1:

Intersection Type

Step 2:

Main Intersection Location

Step 3:

RCI Configurations

Intersection Operations

Safety

Other Considerations

Benefit-Cost Analysis

Consultant Recommendation of Technically Feasible Option (Long-Range) – Download PDF

The recommended technically feasible option reflects a long-range vision for the US16/Neck Yoke Road area. This recommendation will be used to help guide the identification and implementation of future projects in the area.

The recommended technically feasible option that best meets the established transportation needs of the US16/Neck Yoke Road intersection area is Build Option 1.1d, a single RCI at a shifted south Neck Yoke Road intersection.

Recommendation – Reduced Conflict Intersection (RCI)

Key Benefits:

• Greatest expected reduction in crashes
• Up to 70% reduction in Fatal and Injury crashes
• Up to 64% reduction in Total crashes
• Intersection operations reflect LOS A.
• US16 mainline through traffic does not need to stop through intersection (free movement)
• Increases separation between US16 mainline and US16 service road intersection
• Local network connectivity to parcels provided via frontage roads

Base Option Reflective of Proposed FY 2025 Project Elements

The SDDOT is planning to incorporate an incremental approach to implementing improvements and working towards the long-range vision for the US16/Neck Yoke Road intersection area. A Base Option was developed to reflect proposed elements to be incorporated as part of the planned Fiscal Year 2025 Project and carried forward to the NEPA (environmental) process.

Proposed Elements

A number of proposed elements address the project Purpose and Need and reflect the first step in working towards the long-range vision for the US16/Neck Yoke Road intersection area.

• Neck Yoke Road realignment
• Main intersection located at 1.1d RCI main intersection location
• Increases separation between US16 mainline and US16 service road
• Access management at minor access intersections north of Neck Yoke Road
• Access closures
• Restricted movements at maintained access points
• No left turns or through movements out of minor access points reduces crossing conflicts
• Can incorporate widened cross-section for median U-turn north of Neck Yoke Road
• US16 mainline bridges do not need to be reconstructed

Other Build Options Considered – Download PDF

1.1a: RCI at Neck Yoke Road

• RCI at Neck Yoke Road intersection
• All area access points consolidated to main RCI
• New frontage road on west side of US16

1.1b: RCI at Neck Yoke Road plus Northern ¾ Access

• Similar to 1.1a
• Adds ¾ access at north Reptile Gardens/US16 service road intersection

1.1c: RCI at Neck Yoke Road plus Northern Partial Access

• Similar layout to 1.1b
• Lone difference is omission of EB to WB U-turn at the northern partial access to reduce number of conflict points

1.1d: RCI at Neck Yoke Road (West)

• RCI at Neck Yoke Road intersection, shifted 250 feet west
• All area access points consolidated to main RCI
• New frontage road on west side of US16

1.1e: RCI at Neck Yoke Road (West) plus Central Partial Access (2 options)

• Similar layout to 1.1e
• Adds partial access at central Reptile Gardens/US16 service road intersection
• Option with and without frontage road on west side of US16

1.2a: RCI at Central Driveway

• RCI at central Reptile Gardens/US16 service road intersection
• All area access points consolidated to main RCI
• New frontage road on west side of US16

1.2b: RCI at Central Driveway plus Northern ¾ Access

• Similar to 1.2a
• Adds ¾ access at the northern-most US16 service road intersection

1.3a: RCI at Central Driveway with US16 Realignment

• Similar to 1.2a
• US16 alignment shifted west (20 feet) to increase separation from US16 service road

1.3b: RCI at Central Driveway with US16 Realignment plus Northern ¾ Access

• Similar to 1.2b
• US16 alignment shifted west (20 feet) to increase separation from US16 service road

2.1a: Signalized Intersection at Neck Yoke Road

• Signalized intersection (when warranted) at Neck Yoke Road intersection
• Third eastbound lane required to meet signalized intersection LOS goals
• All area access points consolidated to main signalized intersection
• New frontage road on west side

2.1b: Signalized Intersection at Neck Yoke Road plus Northern ¾ Access

• Similar to 2.1a
• Adds ¾ access at north Reptile Gardens/US16 service road intersection

2.2a: Signalized Intersection at Central Driveway

• Signalized intersection (when warranted) at central Reptile Gardens/US16 service road intersection
• Third eastbound lane required to meet signalized intersection LOS goals
• All area access points consolidated to main signalized intersection
• New frontage road on west side

2.2b: Signalized Intersection at Central Driveway plus Northern ¾ Access

• Similar to 2.2a
• Adds ¾ access at the northern-most US16 service road intersection

Full Evaluation Matrix:

Segment Overview

American Buffalo Resort Area Intersection Options – Download PDF

Scenario 1: Single Full Access Intersection and Main Entrance

• Full access main resort entrance
• Eastbound left turn lane extension
• Median through or closure of all other access points
• Frontage road

Benefits:

Drawbacks:

• Does not eliminate angle conflicts for left turns out of main entrance
• EB US16 left turn on 6% down grade
• Frontage road divides existing resort features

Scenario 2: Frontage Road to 47th Avenue

• Median through or closure of all other access points
• Frontage road to 47th Avenue West
• RIRO at east end to provide circulation

Benefits:

• Greatest reduction of conflict points
• 10% reduction in predicted F&I crashes
• Eliminates right angle conflict for left turns out of all existing access points
• Removes EB US16 left turn from 6% down grade
• Greatest separation between US16 and first frontage driveway access

Drawbacks:

• Highest cost
• Wilderness Canyon Road approximately 0.6 miles from main entrance
• Signing/wayfinding will be important for eastbound traffic as resort is not visible form Wilderness Canyon Road intersection
• Frontage road divides existing resort features

Scenario 3: RCI at Main Entrance

• RCI (full access) at main resort entrance
• Eastbound left turn lane extension
• Median through or closure of all other access points
• Frontage road

Benefits:

• 10% reduction in predicted F&I crashes
• Eliminates right angle conflict for left turns out of all existing access points

Drawbacks:

• EB US16 left turn on 6% down grade
• Frontage road divides existing resort features

Bear Country/Croell Quarry Area Intersection Options – Download PDF

Scenario 3: Intersection Improvements

• Bear Country Entrance
• Maintain eastbound left turn lane
• Westbound right turn lane extension
• Bear Country Exit
• Median U-turn intersection
• Croell Quarry Main Intersection
• Eastbound left turn lane (2020 project)
• Southbound to eastbound acceleration lane (2020 project)

Rushmore Candy Company Access Option – Download PDF

Scenario 1: Modified RCI

• RCI at west access
• Adds eastbound left turn lane
• RIRO at east access

Croell Quarry Horizontal Curve

High friction surface treatment was added to the eastbound direction in Fall 2019. SDDOT has seen significant benefit statewide from these applications in reducing run off the road crashes, which has been an issue through this curve.

Segment Overview

Corridor Build Options – Download PDF

Scenario 1: Reduced Conflict Intersections (RCIs) on Existing Alignment

• RCIs at Wilderness Canyon Road, Busted Five Lane, and Strato Rim Drive
• Christmas Store (and surrounding parcels) access options:
• RIRO, ¾, or rearage connections to Strato Rim Drive or Busted Five Lane

Benefits:

• 31% predicted reduction in F&I crashes
• All intersection approach delay LOS C or better
• Greatest B/C ratio (2.10)

Drawbacks:

• Some U-turns may line up with existing access points, which creates new turning conflicts (mitigation possible)
• Frontage/rearage connections could add to cost

Scenario 2: Full Access Intersection Improvements on Existing Alignment

• Wilderness Canyon Road, Busted Five Lane, and Strato Rim Drive intersection improvements
• Southbound to eastbound left turn acceleration lane
• Warranted turn lanes
• Christmas Store (and surrounding parcels) RIRO access

Benefits:

• 13% predicted reduction in F&I crashes
• Facilitates single-stage side-street left turn movement (left turn into acceleration lane)

Drawbacks:

• Greatest stop-controlled delay at all three intersections
• Least safety benefit of corridor scenarios

Scenario 3: RCIs on Shifted South Alignment

• New US16 alignment shifted south
• Rural cross-section
• 250-foot separation between US16 and first side-street driveway or intersection
• Strato Rim Drive/Busted Five Lane combined RCI at 0.5-mile spacing from Wilderness Canyon Road
• RCI at Wilderness Canyon Road

Benefits:

• Greatest reduction in total number of conflict points
• 32% predicted reduction in F&I crashes
• All intersection approach delay LOS C or better
• Greatest separation between US16 and first crossroad intersection

Drawbacks:

• Requires reconstruction of US16
• Greatest cost and ROW need

All Scenarios

Benefits:

• Improves intersection traffic operations
• Improves predicted safety
• Reduces total number of conflict points
• Provides access framework for future development

Evaluation Summary

Click the image above to enlarge.

Segment Overview

Corridor Build Options – Download PDF

All three scenarios were developed to provide the following benefits:

• Remove redundant ramps
• Improve local network connectivity and reduces need for short-distance local travel on US16
• Reduce total number of intersection conflict points
• Support area-wide incremental improvements through a long-range plan
• Provide access framework for future development

Scenario 1: Maintain Split US16 EB and WB Lanes with Area Improvements

• Maintains existing US16 alignment
• Removes redundant ramps
• Pine Haven Drive extension to Rockerville Road
• US16 EB/Rockerville Road intersection improvements (skew)
• US16 WB/Main Street intersection improvements (skew and sight distance)

Benefits:

• Does not require US16 mainline reconstruction
• Up to 29% predicted reduction in F&I crashes
• Removes internal roadways near potential wetland areas

Drawbacks:

• Some intersection options increase need for short-distance local travel on US16

Scenario 2: Combine US16 EB and WB Lanes on North Side with Area Improvements

• Reconstructs US16 north of Rockerville (existing US16 WB ROW)
• Removes all ramps
• Pine Haven Drive extension to Rockerville Road
• US16 Intersection improvements (RCIs)

Benefits:

• Removes all ramps
• 51% predicted reduction in F&I crashes
• Rockerville development no longer within US16 median
• Removes wildlife barrier with current US16 split, improves habitat connectivity

Drawbacks:

• Requires reconstruction of US16
• Cost
• Larger US16 footprint crossing potential wetland areas

Scenario 3: Combine US16 EB and WB Lanes on South Side with Area Improvements

• Reconstructs US16 south of Rockerville (existing US16 EB ROW)
• Removes all ramps
• Pine Haven Drive extension to Rockerville Road (two options)
• US16 Intersection improvements (RCIs)

Benefits:

• Removes all ramps
• 44% predicted reduction in F&I crashes
• Rockerville development no longer within US16 median
• Removes wildlife barrier with current US16 split, improves habitat connectivity
• Removes US16 and internal roadways near potential wetland areas

Drawbacks:

• Requires reconstruction of US16
• Cost
• Potential for greatest rock excavation impact outside of existing ROW
• Additional local network may be required when compared to Scenario 2

Hillside Country Cabins Access and Silver Mountain Road Intersection Option

Conceptual layout looks at potential westbound left turn lane and eastbound right turn lane into Hillside Country Cabins to gauge feasibility and potential impacts. Turn lanes were noted as possible safety improvements to remove slow or stopped turning traffic from the US16 mainline through lane.

Evaluation Summary

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Plan Overview

The US16 Urban Area Pedestrian and Bicycle recommendations present a long-range plan for facilities along the urban area US16 corridor. This plan serves as an overarching guide for incorporating shared-use path and sidewalk facilities in future projects and promoting a continuous and connected network.

Key Features:

• Continuous shared-use path on east side of US16 corridor
• Continuous sidewalk on west side of US16 corridor south of Tower Road
• Located west of US16 service road to minimize pedestrian/vehicle conflicts

Potential connections to existing and future facilities are noted in the figure. Coordination with future development is encouraged to identify other beneficial ‘mid-segment’ connections.

Potential Bicycle/Pedestrian Underpass Locations

Grade-separated (underpass) bicycle/pedestrian crossings of high-speed, high-volume corridors is a notable benefit to bicycle/pedestrian safety, corridor/intersection traffic operations, and area multimodal connectivity. Potential underpass locations have been identified for further consideration within the US16 urban area based on:

• Locations
• Close proximity to existing/planned major intersection to encourage use of underpass instead of at-grade intersection
• Along potential high-use routes
• Distributed across the corridor to minimize out-of-the-way travel
• Natural low spots where existing terrain is conducive to constructing a bicycle/pedestrian underpass

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Plan Overview

Construction of local network roadways along the corridor are driven by development, that as areas are developed, the roadway network will be constructed with tie points to existing infrastructure. To date, City of Rapid City, RCAMPO, and SDDOT area planning has provided the framework for the future local roadway network through the Rapid City Major Streets Plan.

The US16 Urban Area Local Network figure builds upon the Rapid City Major Streets Plan to incorporate the Consultant Recommendation of an SPI at US16/US16B/Catron Boulevard. This figure represents a long-range access and local network connectivity plan for the US16 urban area surrounding the US16/US16B/Catron Boulevard intersection.

Plan Overview

The ITS recommendations figure presents potential ITS technologies and deployment locations for consideration as part of improvements to the US16 corridor. These recommendations can be used as a guide to implement technologies as part of future corridor projects and/or SDDOT statewide ITS programs.

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Concepts Overview

As part of the US16 Corridor Study, long-range interchange concepts were developed at US16/Moon Meadows Drive and US16/Neck Yoke Road areas to assess feasibility of illustrative interchange footprints in those locations. These concepts were not analyzed beyond developing an illustrative footprint.

Traffic operations analysis conducted at part of the corridor study does not identify any capacity-related need for grade-separated interchanges at either location within the study’s 2050 Planning Horizon. However, as volumes continue to grow along the US16 corridor and Rapid City development continues southward, there may be a time when it is desirable to separate east/west traffic conflicts from US16.

Conceptual interchange locations correlate to proposed arterial roadways identified in the City of Rapid City Major Street Plan.

• Moon Meadows Drive: proposed east/west Principal Arterial extension east to SD79
• Spring Creek Road: proposed Principal Arterial extension across US16 to the northwest
• Spring Creek Road currently connects to SD79

Interchange Concepts – Download PDF

US16/Moon Meadows Drive Interchange Concepts

Both scenarios reflect a SPI at US16/US16B/Catron Boulevard intersection and overpass at Section Line Road intersection.

Scenario 1: Diamond Interchange

Scenario 2: Single Point Interchange

US16/Neck Yoke Road Area Interchange and Local Network Concepts

Local network alignment concepts

Standard diamond interchange south of Neck Yoke Road

Tight diamond interchange north of Neck Yoke Road

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Project Schedule

Review the high-level schedule below to see how the project has progressed. Final reports are tentatively scheduled for delivery in late 2021.

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Level of Service Definitions

Level of service (LOS) is a quantitative stratification of performance measures representing quality of service, or how well a transportation facility operates from a traveler’s perspective.

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Reduced Conflict Intersections (RCIs) are also known as J-turns or RCUTS. They are alternative intersections for four-lane divided highways. Drivers on the minor-road no longer expose themselves to the most common and severest crash type: the right-angle crash (also called the T-bone, broadside, or perpendicular). Minor road drivers now complete a series of maneuvers that decrease the probability of a severe crash and reduce the risk of death or serious injury.

Example Rural RCI

How Does an RCI Work?

Further Reading:

• MnDOT FAQs
• MnDOT RCI Information
• FHWA Informational Guide

Tell Us What You Think

Input collected will aid in the development of study recommendations and general timeline for implementation.

• Questions and comments will be accepted February 28, 2021 and may be submitted through the study website or by reaching out to one of the project representatives via email or phone.

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