Flawed decision-making and poor contract management contributed to billions in cost overruns and years of delays in the as-yet unbuilt California’s high-speed rail line between Los Angeles and San Francisco, state auditors said Thursday.

The project is now estimated to cost $77 billion and is 15 years from completion.

State auditor Elaine Howle faulted the California High-Speed Rail Authority for starting limited construction in 2013 before it completed critical tasks like buying land, relocating utilities or obtaining agreements from outside groups including local governments and other railroad operators.

That led to numerous contract changes, project delays, and overruns that have led to a nearly doubling of the original cost estimate of $40 billion.