3.5 Single Toll-free Statewide Telephone Number with Nationwide Access
All one call centers have a single toll free statewide telephone number with nationwide access.
There is only one statewide toll-free telephone number for one call centers to receive locate requests. This number has nationwide access, meaning that a caller can reach the center from anywhere in the country.
One Call Systems International Voluntary Recognition Program
Existing operating practices from various states’ one call centers
49 CFR Part 198
NTSB Safety Study (NTSB/SS-97/01; PB97-917003)