The mayors of Metro Vancouver have rejected the provincial government's plans to replace the George Massey tunnel with a 10-lane bridge.

It's the first time the mayors, who make up the Metro Vancouver Board, have spoken out collectively against the $3.5-billion crossing.

The decision came as the board released a report assessing the impact of the bridge on the region's traffic congestion and the environment.

"History has demonstrated the world over, you can't reduce congestion by simply building more roads," said board chair Greg Moore in a written statement.

"This project represents an expansion of car-oriented infrastructure and diverts crucial funds from transportation projects that support the regional growth strategy."

The board said that while it understands the need to reduce traffic congestion along the busy Highway 99, it questions how the $3.5-billion bridge would resolve those issues.

Moore said the board would prefer to see a smaller bridge with more lanes dedicated to public transportation.

Big criticism is having 8 lanes of single occupancy traffic. Mayors want to see better options for transit in a replacement project. —@FarrahMerali

He also expressed concerns about charging drivers to cross the bridge, which would leave commuters without a toll-free route.

The report highlights the following issues:

Insufficient consideration of alternatives to a ten-lane bridge.

Lack of integration into the regional growth strategy and transportation network.

Ecological disruption to the Fraser River estuary, an important habitat for salmon and birds.

Impacts on Metro Vancouver infrastructure, including water mains and sewer lines.

Recreational and ecological disruption on Deas Island Regional Park.

Downloading of major expenditures onto local governments for road improvements.

Negative effects on transit ridership and affordability.

Insufficient consideration to climate change and air quality.

"We are genuinely concerned about the possible impacts of bridge construction, roadway improvements, tunnel removal and possible future dredging which could impact between $500 million to $1 billion in regional infrastructure and assets," said Metro Vancouver utilities committee chair Darrell Mussatto.

An artist's rendering of the proposed bridge to replace the George Massey tunnel. (Province of B.C.)

The board said it was also concerned about a lack of public consultation on the project.

It said it will send a letter to the province about the report and its analysis, highlighting its concerns.

The province announced plans last December to replace the aging George Massey Tunnel with what would be the largest toll bridge in the province.

Transportation Minister Todd Stone argued the bridge would reduce greenhouse gas emissions by reducing unnecessary idling and would save commuters up to 30 minutes a day of travel time.

The three-kilometre bridge will connect Richmond and Delta across the Fraser River.

Construction is expected to begin in 2017 and would take about five years.

With files from Farrah Merali