This paper presents a new estimate of the frequencies of leaks of dangerous goods (DG) from tankers on public roads. This new estimate is needed because existing published leak frequencies are based on data collected in the 1980s, which may no longer be applicable. The new frequency is based on reports from DG vehicles in France during 2003-2013. This provides comprehensive coverage of leaks from a large population of DG vehicles. Corresponding activity data comes from annual surveys of DG vehicles. Although they do not explicitly collect bulk road tanker activity, an approximate estimate is developed. The analysis provides leak frequencies per vehicle-km and per tonne-km. Results are distinguished for Class 2 gases, Class 3 flammable liquids and Class 8 corrosives. The results are expressed as leak frequency-quantity distributions, making use of the large dataset to define the frequencies of tank ruptures as well as smaller leaks. The paper compares the new frequencies with previously published estimates. It appears to be a credible, highquality and up-to-date estimate, which provides better definition of the frequencies than any previous source. It forms a good basis for future road transport risk assessments. Surprisingly, it implies that the road tanker industry has achieved no improvement in leak frequencies since the 1980s, despite a substantial improvement in overall road safety.