To determine which crossings are eligible for safety improvements, such as flashing signals and automatic gates, NCDOT derives the "Investigative Index" – a numerical index updated annually – based on the following factors:
Average daily vehicle traffic
School bus passenger loads
Existing warning devices
Number of main-line tracks and side tracks in use
The crossing's most recent 10-year accident history
The higher the index value, the higher the priority for improvement. The approximately 100 crossings with the highest indices are selected as candidates for improvement.
NCDOT also takes into consideration other projects at the crossing as well as current studies and projects by other entities.
Engineers examine each crossing under consideration. Based on their recommendations as well as available funding, NCDOT selects as many crossings as possible and assigns priorities for improvements. Annual funding has averaged nearly $9 million in recent years, with some increase in funding levels provided through the federal Transportation Equity Act.
After the selected crossings have been added to the Crossing Hazard Elimination Program, new projects are submitted to the N.C. Board of Transportation for approval as additions to the State Transportation Improvement Program.
Where municipal streets rather than state-maintained roads are affected, cities and towns are required to pay 10 percent of the cost of installing grade-crossing warning devices. (Municipalities and the railroad companies split the cost of maintaining those devices.)
Whenever a city or town signs an agreement with the state to participate in a project, NCDOT will proceed in the same manner as other state road projects.
If the municipality decides not to participate, the project is dropped from the State Transportation Improvement Program but remains under consideration by NCDOT for the future.