Roads and Bridges

County Roads and Bridges

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Roads and bridges in Texas are generally designed, constructed, and maintained by either the Texas Department of Transportation (TxDOT) or by individual counties.  “On-system” roads generally refer to roads administered by TxDOT, while “off-system” roads are those that are not administered by TxDOT; these are almost exclusively county roads.  TxDOT roads are designed, constructed, and maintained according to a set of standards which apply statewide.  These TxDOT standards are recognized by the EPA as being protective of water quality.

One key task in this project is to collaborate with county officials responsible for off-system roads and bridges that are located outside of MS4 permitted areas.  County roads are designed, constructed and maintained by individual counties.  Counties may choose to adopt TxDOT standards for all or part of the design, construction and maintenance of their roads, but are not required to.

The entire collection of TxDOT manuals can be found here:

To facilitate access to the portions of these manuals that are most relevant to stormwater quality and quantity, the links are posted below:

Additionally the Stormwater Field Inspectors Guide (2004) provides detailed information regarding Stormwater Management Plans and Best Management Practices for roadway construction:

TxDOT provides guidance regarding stormwater runoff as well as outlines requirements for elements that provide incidental water quality benefits, such as corridors that act as vegetative filter strips.

County roads in Texas fall into one of two systems.  In the first system, called the unit road system, county road design, construction, and maintenance is centralized under a county engineer. In the second system, called the precinct system, each county commissioner may have individual responsibility for the roads in his or her precinct.

Under the unit road system, the county engineer is responsible for overseeing the design, construction and maintenance of county roads and bridges.  The engineer is responsible for prioritizing new construction, for determining which roads are eligible for reconstruction or repair, and for supervising the Roads and Bridges crew.  Of the counties in the Coastal Zone, Orange, Chambers, Galveston, Brazoria, Aransas, Nueces, and Cameron Counties are on the unit road system.

In the precinct system, decisions about roads are made on a precinct level by individual county commissioners; therefore there is often not a county-wide set of standard guidance. The Commissioners Court is comprised of the four county commissioners and is presided over by the county judge. County commissioners are elected by the residents of their precinct and are responsible for all aspects of road construction and maintenance. Of the counties in the coastal zone, Jefferson, Harris, Matagorda, Jackson, Victoria, Calhoun, Refugio, San Patricio, Kleberg, Kenedy, and Willacy Counties are on the precinct system.