This final rule amends the gas, hazardous liquid and carbon dioxide pipeline safety regulations to require that certain new and replacement pipelines be designed and constructed to accommodate the passage of instrumented internal inspection devices (smart pigs). This action was taken in response to a mandate in the Pipeline Safety Reauthorization Act of 1988. The intended effect' of these amended regulations is to improve the safety of gas, hazardous liquid and carbon dioxide pipelines by permiitting their inspection by "smart pigs" using the latest technology for detecting and recording abnormalities in the pipe wall.