10.3.3 Basic Safety Improvements
Basic safety improvements will be required for all 3R projects. Basic safety improvements are defined as:
- Upgrading guard fence to current standards;
- Providing signing and pavement markings in accordance with the and the ;
- Providing a skid-resistant surface; and
- Safety end treating cross drainage pipe culverts 36 inches in diameter or smaller that are inside the respective clear zone.
Other safety improvements to consider include treatment of nonstandard mailbox supports, nonstandard luminaire supports, and nonstandard sign supports that are inside the suggested clear zones. Treatment of trees, utility poles, or other obstacles that are indicated during a crash evaluation should also be considered.
10.3.3.1 Metal Beam Guard Fence
Metal Beam Guard fence must be upgraded to current roadside safety hardware standards. Connections to structures, post spacing, and end treatments must meet current design practices, and standards. See
for specific guidance on Metal Beam Guard Fence requirements. Metal Beam Guard fence lengths will generally be designed to requirements given in
.
Remove all nonessential guard fence and guard fence where shielded obstacles may be cost-effectively design treated (removed, made yielding, slope regrading/improvement, etc.).
10.3.3.2 Headwalls
Remove headwalls on small (36 inches or less) cross drainage pipe culverts that are inside the respective clear zone and install sloping (1V:3H or flatter) culvert ends (a.k.a., safety treatments) that blend with existing side slopes. Where located behind guard fence, these culvert ends should be safety end treated and the guard fence removed where there are no other obstructions involved.
10.3.3.3 Cross Drainage Culverts
Cross drainage box and pipe culverts greater than 36-in may remain in place where the clear zones are satisfied. Where the clear zones are not met, safety treatment (grates, extension, or guard fence) will be required. In situations where the culvert end meets clear zone requirements, yet other culverts within the project limits are treated, consider safety treatment to provide consistency within the project area. Where guard fence is required for shielding other non-removable obstacles, headwalls behind guard fence do not need to be safety treated.
For culvert spans from 3-ft to 5-ft and heights up to 5-ft that need to be safety treated, pipe grated design is very effective from a safety standpoint and generally cost effective from an economic standpoint. If sloping or grated inlet designs are utilized for these low height and width culverts and their past performance has not been satisfactory, then evaluate inlet restrictions (entrance loss coefficients) for their effects on hydraulics. If necessary, refer to TxDOT’s
for entrance loss coefficients with various configurations as well as other hydraulic design information.
The ends of bridge-class pipes and culverts must be protected whether they are inside or outside of the clear zone, see
for additional guidance.
10.3.3.4 Driveway Embankments and Pipes
Treat driveway embankments and pipes on 3R projects only where other design improvements necessitate their reconstruction or when they are located inside the clear zones given in this chapter.
The extent of the safety improvement selected for a particular project may be influenced by the extent of other work. Where pavement improvements extend pavement life substantially, consider more significant geometric and safety-related improvements.