Managing Agency Texas Department of Transportation (TxDOT) The TxDOT Dallas District plans, designs, builds, operates, and maintains the state transportation system in the following counties: Collin, Dallas, Denton, Ellis, Kaufman, Navarro and Rockwall. The TxDOT Collin County Area Office led by Area Engineer Jennifer Vorster, PE, is responsible for all TxDOT work within Collin County....