BART's Board of Directors on Thursday is expected to make a pivotal decision that could determine whether the transportation agency extends into Livermore.

Stretching BART an extra 5.5 miles east along Interstate 580, specifically to the proposed location at the intersection of Isabel Avenue and Airway Boulevard, will cost an estimated $1.6 billion, with more than $1 billion still needed to be raised, according to the Mercury News.

BART's board on Thursday will have two decisions to make: whether to approve the final environmental impact report for the Livermore extension project and what to do next.

When it comes to what's potentially next, BART has five options on the table. The transportation agency could extend regular BART tracks to the proposed Isabel Avenue and Airway Boulevard location. BART could also expand into Livermore using light rail equipment such as trains that run on diesel or electric power, but that project would require passengers to transfer at the Dublin/Pleasanton station. Two more options involve utilizing buses. The final option is the board could do nothing about an extension.

The proposed extension stops several miles short of the Altamont Pass. Critics say the idea of stopping BART at the Isabel Avenue and Airway Boulevard location would not help alleviate the traffic crunch that bottles up Interstate 580 during the workweek.

BART's Board of Directors is slated to meet at their Oakland headquarters at 5 p.m. Thursday to address the extension. There will be an opportunity for citizens to offer public comments.