Alternatives 

Overview of Process to Determine, Present, and Select Feasible Alternatives

Initially, a range of alternatives are developed based upon past and ongoing alternatives and studies, stakeholder and public input/recommendations, agency input, and design standards. Once this range of alternatives are established, they are funneled through a 2 tiered screening process.
Tier 1 Screening
The Tier 1 Screening evaluates each alternative to determine if it meets the primary purpose and need as well as minimum design criteria. The alternatives that pass this screening will move forward to the Tier 2 Screening.
Tier 2 Screening
The Tier 2 Screening will evaluate which of the preliminary alternatives (from the Level 1 Screening) best meet the primary purpose and need while also considering the degree to which these alternatives meet the secondary purpose and need, their impacts on the natural and human environment, estimated project costs, and overall feasibility. Only the alternatives that meet these criteria will be advanced for consideration as Reasonable Alternatives.
The alternatives that are not eliminated through the Tier 2 Screening process will be further refined through preliminary engineering before detailed impact analyses begin for the environmental assessment. The preliminary design for roadway will include details such as number of lanes, horizontal and vertical alignments, typical sections, right of way limits, intersection layouts, and construction limits.

Each reasonable alternative will be designed to a similar level of detail. Once the preliminary design work is complete, the potential effects of the alternatives will be identified and compared at an equal level of detail. The reasonable alternatives will be detailed in the Environmental document with the ultimate goal of selecting a Preferred Alternative that would meet the overall purpose and need of the project while avoiding and minimizing environmental impacts to the greatest extent practicable.

In this section

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Alternative Analysis

A Range of Alternatives was developed using data from previous studies, traffic modeling and evaluation, environmental impacts, agency input, and community and stakeholder input. The Range of Alternatives were funneled through Screening Level 1, which evaluated each alternative based on the purpose and need and minimum design criteria.

Alternatives that passed Screening Level 1 are considered Preliminary Alternatives, shown as Alternatives 1 - 4. The alternatives include different levels of improvements on HWY 78. All alternatives include the same improvements at the Hwy 78/College Park Road/Ladson Road intersections.

Tier 2 Screening

Preliminary Alternatives were funneled through Screening Level 2, which evaluated each alternative based on the following criteria:

  • Traffic Operations
  • Public & Stakeholder Input
  • Cost

Alternatives that pass Screening Level 2 are considered Reasonable Alternatives.

Alternatives that pass Screening Level 2 will be considered Reasonable Alternatives. Reasonable Alternatives will undergo additional design and analysis.
View Graphic
View Graphic

Traffic Operations

The Project Team completed a Traffic Study that analyzed the existing and future conditions for the no-build and the build alternatives. This study looked at Level of Service at intersections along the corridor and segments of Hwy 78. When comparing the Level of Service (LOS) between a three-lane section (consisting of two travel lanes and a two-way center turn lane) from Berlin G. Myers to the Fairgrounds (Alternative 2) and a five-lane section (with four travel lanes and a two-way center turn lane) in the same area (Alternatives 3 and 4), the three-lane section exhibits better performance and experiences less decline in the later year (2049) as analyzed in the traffic study. While a five-lane section would offer additional capacity, it also is shown to attract more traffic to the corridor for users from the Summerville area to access I-26 and points east.

View Graphic

Public & Stakeholder Input

Alternatives were presented at a Public Meeting on May 8, 2024. There was a total of 135 attendees. Comments predominantly agreed changes need to be made within the project area. A few concerns raised across the majority of submitted comments include:

  • Generic
    • Support for improving the US 78 Corridor.
    • Concern for flooding and water runoff.
    • Alternative 2 received 8 supportive comments, Alternative 4 received 4 supportive comments, but none of the alternatives were widely supported.
  • Traffic
    • Concerns about increased traffic congestion.
    • Morning and evening hours are the most congested.
    • How will the Lowcountry Rapid Transit (LCRT) affect traffic and the alternatives presented?
  • Safety
    • Support for restricted median
    • Concerns with TWLTL for left turns across 2 lanes of traffic
    • Several comments mentioned 4 lanes (2 in each direction) are preferred over 5 lanes.
  • Intersections
    • Need traffic light at Wisteria/US 78
    • University Blvd, Wisteria Road, and Berlin G Myers are repeating areas of concern
  • Timeline/Schedule
    • Concern with 2027-2029 being too far away, consider expediting project schedule
  • Support for Bike/Pedestrian Accommodations

Cost

Costs for each alternative were evaluated at a high level. Generally, as more improvements are added to alternatives, the cost goes up, with Alternative 1 being the lowest cost and Alternative 4 being the highest. Even with significant improvements (capacity & intersection) and cost, LOS at many locations still declines in the future when compared to the no build alternative due to the increased capacity drawing additional traffic to the corridor.

Alternatives Screening Graphic

View Graphic

Reasonable Alternatives

Based on a review of traffic operations, public and stakeholder input, and costs, Charleston County has decided that only improvements at the Hwy 78/College Park Road/Ladson Road intersections are reasonable. Alternatives for the HWY 78 Corridor do not offer sufficient traffic benefits for their high costs.

College Park Road and Ladson Road Intersection

Charleston County Public Works 
Transportation Engineering
Lonnie Hamilton III Public Services Building
4045 Bridge View Drive, Suite B309
North Charleston, SC 29405
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