Low-Volume Road Thickness: RoadPE: LHI Design Tool

The Excel spreadsheet tool, RoadPE:LHI, was developed for low-volume roads under 2,000 vehicles per day. The tool’s name LHI, stands for Low-volume Highway Inputs as a reminder that these inputs and design outputs are only valid for low-volume roads and streets.

The concept is to use some very basic inputs which can be determined by a small highway department and use other precalculated inputs and design assumptions to determine the design thickness of a new asphalt layer. Because the tool makes many basic assumptions, it is not applicable for many collector and most arterial highways.

Using the tool is a three-step process:

  1. Check the Existing Design: Input known information about the location, the pavement structure, and the traffic and check the remaining life of the existing pavement structure.
  2. Run Design Calculations: Only four basic choices are available: overlay, mill and fill, rehabilitation, reconstruction. Once the user selects the type of work to be completed, the anticipated design life, and some other basic inputs, the tool will determine the thickness of a new asphalt layer.
  3. Tweak the Final Design (or check existing assumptions): Because the tool uses basic assumptions, the user has an opportunity to tweak the final design as needed. This includes checking each step of the initial design.

Specific details for the use and application of the RoadPR: LHI Design Tool are found in the instructions.