Texas Transportation Commissioner Deirdre Delisi submitted her resignation to Gov. Rick Perry today. Now, she will have more time to devote to his presidential campaign.

Delisi, a close adviser and former chief of staff to Perry, is currently serving as a policy and strategy director on his presidential campaign. But for the last three years she has been at the helm of the transportation agency's governing board.

The agency has experienced significant change in that time. They recently announced a new executive director: Delisi's fellow former Perry aide and former Secretary of State Phil Wilson.

A spokesman for the Transportation Commission said that the timetable for Delisi's replacement  — or who might replace her — is not  yet known.

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In a letter to the current interim executive director John Barton, Delisi wrote, "Over the past three years, we have made tremendous progress, including a positive Sunset Review and embarking on a path of modernization. The steps along the way have not always been easy, but we persevered and TxDOT is a better, stronger agency for it."

Here is her full letter:

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