SAN FRANCISCO (KRON) — The battle over the Golden State Warriors’ proposed new $1 billion arena is heating up as a group of opponents on Tuesday plans to raise their concerns about traffic and parking before city officials.

San Francisco’s Mission Bay neighborhood has been designated for the NBA championship team’s 18,000-seat arena and entertainment center. But the project is facing a major showdown as the Mission Bay Alliance, a newly formed coalition that includes UCSF stakeholders, donors, and faculty point to an environmental report that it says gives the project a flunking grade on the subject of traffic in the area.

On Tuesday, the Mission Bay Alliance along with other representatives from the UCSF healthcare community plan to share those concerns during a public hearing, as they highlight findings of the recently released draft environmental impact report (EIR). The opponents are worried the arena will create dangerous delays for patients and physicians trying to get to the new UCSF Benioff Children’s Hospital San Francisco at Mission Bay.

“The draft EIR shows that the Warriors’ proposed entertainment complex in Mission Bay fails major intersections and will grind traffic in Mission Bay to a screeching halt during games and events,” said Bruce Spaulding of the Mission Bay Alliance. “While our team of attorneys continues to review the project, the draft EIR admits this project will have significantly negative impacts on nearby residents and UCSF patients and healthcare workers.”

The group says major intersections in the area receive a failing score of “E” and “F” during special events, according to the report’s “Level of Service” traffic impact analysis. The scoring calculates the delays per vehicle and assigns an A-F letter grade for each Mission Bay intersection. The Mission Bay Alliance says the report shows the vast majority of those intersections would fail, facing heavy congestion and gridlock during games and special events. The alliance says these problems are anticipated despite substantial transit and transportation investments promised by the city to ease traffic in the area.

City officials are planning a public hearing about the project Tuesday and formal comments to the city’s planning department are due July 20 (45 days after the draft EIR was released), said the Mission Bay Alliance. After an initial review of the EIR, the Mission Bay Alliance’s legal team wants an additional 45 days to review and comment on city documents used to support the environmental report for the project.

“45 days is simply not enough time to meaningfully review and comment on the draft Environmental Impact Report,” said Mission Bay Alliance attorney Tom Lippe in a letter to the city requesting the extension.

The latest move follows a protest on Monday by UCSF nurses who voiced their concerns about the proposed project.