WASHINGTON (AP) — Metro says it has fallen behind on its effort to expand cellphone service throughout the transit system and may not complete the project until 2015.

In a letter to Congress on Tuesday, Metro General Manager Richard Sarles says there is still much work to do to provide wireless access throughout the system. He requests for the project’s deadline to be extended to December 2015.

Sarles says Metro has been focused on safety issues after a crash that killed nine people, so the wireless project has been a lesser priority.

Under a 2008 funding agreement with Congress, Metro was to have completed the project this week. A deal reached last month extended the deadline to March 2013.

Many stations have cellphone service, but connections through underground tunnels aren’t complete.

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