Underground utility infrastructure represents a substantial risk to workers and the public. Most damage to underground infrastructure is the result of construction excavation, recent examples include Murrieta CA, Durham NC, and San Francisco CA. But inadequately maintained, aging and abandoned infrastructure whose location is unknown or poorly known is also a significant hazard as shown by the events in St Bruno, Merrimack, and Lawrence. It is instructive to compare statistics for incidents in the commercial airline industry with those for underground utility damage. But whereas the number of fatalities and incidents involving commercial aircraft in the U.S. has declined consistently from its high in 1929, the latest Common Ground Alliance DIRT Report reveals that the number of underground utility damage events in 2018 shows no indication of decreasing from previous years, even when prorated to the total construction spending per year.
Metrics and trends for commercial airline incidents
Reliable metrics make it possible to assess the social and economic impact of incidents and the effectiveness of new technologies and policies in preventing and reducing the severity of these incidents. In the commercial airline industry there have been reliable statistics since the early 20th Century. In 1929 there were 51 commercial airline incidents, which represents an accident rate of about 1 for every 1,000,000 passenger miles. If that rate is prorated to the current total number of revenue passenger miles this would be equivalent to 7,000 fatal incidents per year. Fatal accidents per million flights in 2018 have decreased 16 fold since 1970, from 6.35 to 0.39, and fatalities per trillion revenue passenger kilometers (RPK) decreased 54 fold from 3,218 to 59 in 2018. For the most recent two decades major commercial airline incidents in the U.S. resulted in 403 fatalities (excluding 9/11).
Very good data is collected and is accessible about individual airplane incidents that help the FAA and others determine the causes of airline incidents such as the recent Boeing 737 Max 8 accidents.
Metrics and trends for underground utility damage
The CGA DIRT report and the the Utility Strike Avoidance Group (USAG) in the UK are a first step in the direction of reliable statistics for underground utility damage, but they seriously underestimate the number of incidents, do not report statistics on casualties, and only collect data on direct costs, not on indirect and social costs.
The first DIRT Report was released in 2004. Since then the number of incidents of underground utility damage voluntarily reported to the Common Ground Alliance has increased. The DIRT Report for 2018 shows that the total estimated damages in the U.S. increased from 439,000 in 2017 to 509,000 in 2018, representing a 16% increase. Those knowledgeable about the construction industry would not be surprised if the DIRT reports underestimate the total of incidents by a factor of 2X. The CGA has estimated that the direct cost of underground infrastructure damage to the U.S. economy is at least $1.5 billion, but I know of no estimate of the indirect and social cost associated with these damages or of the injuries and fatalities attributable to underground utility data beyond that reported by Pipeline and Hazardous Materials Safety Administration (PHMSA). Since 2005, pipeline operators have reported excavation damage as the cause of 1052 incidents, resulting in 48 fatalities, 195 injuries requiring hospitalization, and $ 481,736,551 of property damage.
In the UK the Utility Strike Avoidance Group (USAG) began collecting statistics on underground utility damage in 2013, but the coverage does not approach that of the CGA. USAG also operates on a voluntary basis with no direct funding other than support from member organizations. The last report issued by USAG was for 2015/1016. There is research that has attempted to estimate the indirect and social cost of underground utility damage in the UK. The total cost of underground utility strikes to the UK economy is estimated to be £1.2 billion a year. I know of no statistics currently available for injuries and fatalities due to damage to utilities in the UK.
For trends over time the CGA breaks out incidents that are reported by "consistently reporting sources" which are sources that have reported incidents in 2016, 2017, and 2018. The CGA believes that these consistently reporting sources can be used reliably to determine temporal trends in the DIRT data. Based on these sources there is no indication that the number of incidents is trending downward.
2016 | 2017 | 2018 | |
Reported damages from consistently reporting sources | 312,046 | 308,783 | 325,606 |
The number of incidents of damages per million dollars of construction spending (2017 constant dollars) actually increased from 0.359 in 2017 to 0.392 in 2018.
For those that may think little can be done about this problem, it is instructive to compare the number of incidents reported in the United States with the number for all of Japan in 2016.
Common Ground Alliance | Japan Construction Industry Association | |
Reported damages 2016 | 390,366 | 134 |
One of the reasons for the huge disparity is that Japan has been maintaining accurate statistics for underground utility damage for many years. Similar to what has happened in the commercial airline industry, Japan began making a serious effort to improve these metrics beginning with improving the quality of information about the location of underground utility infrastructure with the introduction of the ROADIC system in Tokyo in 1985.
This suggests that following the commercial airline industry the priorities for the U.S. and UK are to continue to improve the coverage of the statistics that are being captured for underground utility damage and to begin to implement technologies and policies for long term improvement in these metrics.
Comments