Buoyed by a potential $12.6 million in grant funding, SMART is planning construction of a bike path from Penngrove to downtown Petaluma, the next phase of its pathway project that critics say has lagged commuter rail development.

SMART is in line for the funding this month after the Metropolitan Transportation Commission recommended the North Bay’s rail agency for the grant. It would be used to construct 4.7 miles of pathway segments along the rail line in Santa Rosa, Rohnert Park and from Penngrove to McDowell Boulevard, where it would link up with a planned path from Southpoint Boulevard to Payran Street. Construction is lated for 2021.

“It’s great,” said Supervisor David Rabbitt, a SMART board member. “We’re continuing to move forward. It’s all moving together.”

SMART was billed as a rail and trail system, providing a 70-mile bike path and commuter rail link from Cloverdale to Larkspur. So far, only 16.2 miles of trail have been completed between Santa Rosa and San Rafael. A separate grant SMART received two years ago will fund construction of a bike path from Southpoint to Payran. That’s due to be completed this summer, pending approval of permits, according to Jeanne Mariani-Belding, SMART’s communications and marketing manager.