Table 1: Pipeline Inspection Prioritization Program Variables for Hazardous Liquid and Gas Transmission Pipelines,
For hazardous liquid pipelines:,For gas transmission pipelines:
1. Number of hazardous liquid pipeline accidents reported per mile of pipeline,"1. Miles of coated, but unprotected, pipeline onshore"
2. Number of accidents due to corrosion,2. Miles of bare unprotected steel pipeline onshore per mile of bare steel pipeline onshore
3. Number of accidents caused by incorrect pipeline operating practices,3. Miles of bare steel pipeline onshore per mile of steel pipeline onshore
4. Number of accidents due to failed pipe,4. Number of onshore leaks repaired per mile on onshore pipeline
5. Number of accidents due to failure of field welds,5. Known leaks scheduled for repair per mile of onshore pipe
6. Number of accidents due to outside forces,6. Miles of cast iron pipeline
7. Number of failures of longitudinal welds,7. Miles of “other” pipe
8. Total number of barrels of hazardous liquid spilled,8. Number of transmission incident reports
9. Total injuries and deaths not caused by outside force,9. Number of deaths or injuries not caused by third party damage
10. Number of accidents due to corrosion on non-cathodically protected pipe,10. Incidents due to corrosion per mile of onshore pipeline
,11. Incidents due to construction-related defects per mile of onshore pipeline
,12. Number of incidents due to corrosion on onshore pipelines w/o cathodic protection
"SOURCE:  U.S. Department of Transportation, Pipeline and Hazardous Materials Safety Administration, http://www.phmsa.dot.gov",
NOTE: The difference between accidents (for liquid pipelines) and incidents (for natural gas pipelines) is simply one of terminology. The term “incidents” is often used for both pipeline sectors when a single term is used.,