|Hazardous Liquid pipelines||Gas transmission pipelines|
|~ 300 operators||~ 900 operators|
|~ 50 large operators||~ 90 large operators|
|~ 350 accidents/year||~ 130 incidents/year|
|More of infrastructure data in annual reports||Less infrastructure data in annual reports|
|Integrity Management inspection data for most operators||Less Integrity Management inspection data for operators|
|Overall - more data to work with||Overall - less data to work with|
SOURCE: U.S. Department of Transportation, Pipeline and Hazardous Materials Safety Administration, http://www.phmsa.dot.gov.