Complex sentence: However, the project is at least a decade away from funding as of the late 2000s, while the project itself would likely take 10-15 years once started, according to the New Zealand Transport Agency.
Split into simpler sentences: However, the project is at least a decade away from funding as of the late 2000s. The duration of the project itself would likely take between 5 and 15 years once started, according to the New Zealand Transport Agency.