The SC Department of Transportation met on Thursday, October 18, to approve the addition of mobility targets to the Transportation Asset Management Plan (TAMP). In addition, they also approved the inclusion of the Rural Interstate Freight Network Mobility Improvement Program to the TAMP, which will specifically target rural sections of the interstate system for capacity improvements.
Measuring Mobility
Mobility performance targets are based on two key factors:
1. Performance of Interstate (Percentage of Interstate Segments with Reliable Travel Times*)
2. Movement of Freight (Truck Travel Time Reliability Index*)
*These factors are based on data that is collected at an interval rate (15 minutes) during peak travel times across 1300 segments of the interstate system.
Baseline conditions (2016) and 10-year target figures are outlined below. As you can see these additional investments will not come close to solving problems, but they will serve as an attempt to help ease the decline of mobility.
Source: SCDOT Commission Notebook 10/18/18
The Rural Interstate Freight Network Mobility Improvement Plan will be in addition to the previously approved interstate widening projects planned for the urban areas of the state. It will focus solely on rural sections of the interstate system with a focus on freight density and improving mobility.
The SCDOT plans to allocate $110 million to the program once the fuel tax credit included in Act 40 sunsets in 2023.
Focusing on the movement of freight allows for the SCDOT to improve reliability, productivity, and begin addressing capacity needs on our interstates in areas that they are needed most. While interstates only make up 2% of the system, they carry 30% of the traffic and serve as main arteries of commerce in the state.
Truck freight has grown across the country and will continue to grow in the coming years. In South Carolina, truck freight tonnage is predicted to increase from $375 million to $600 million by 2040.
A total of 18 freight corridors were identified for the program using Metropolitan Planning Organization (MPO) boundaries as the basis.
Source: SCDOT Commission Notebook 10/18/18
The SCDOT also worked in conjunction with the SC Department of Commerce and the SC Ports Authority to better assess economic impacts and mobility of routes.
Each segment was ranked using the following criteria:
• Truck travel time reliability – 0 to 250 points
• Freight tonnage – 0 to 200 points
• Average Annual Daily Truck Traffic – 0 to 200 points
• Potential for economic development – 0 to 100 points
• Service to SC Ports – 0 to 100 points
• Commercial truck crashes – 0 to 100 points
• Connectivity to our existing widened sections – 0 or 50 points
Based on rankings, the top five rural interstate freight segments were identified:
Source: SCDOT Commission Notebook 10/18/18
Source: SCDOT Commission Notebook 10/18/18
SCFOR applauds the SCDOT for working to address additional interstate capacity needs across the state. South Carolina’s roads, especially our interstates, must be able to efficiently move goods and people. The planning and use of analytical data by the SCDOT to identify these corridors to make strategic investments in the coming years is a proactive and responsible approach to managing mobility on South Carolina’s interstates.