171.11 Roadside Appurtenances

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RAP(A1) Crashworthy End Treatments

On high speed (50 mph) and high volume (6000 vpd) National Highway System roads, guardrail approach ends that are damaged beyond repair shall be replaced with crashworthy end sections meeting current standards.

Blunt ends, BCTs and turned downs may still be used on the trailing ends of guardrail, on one-way highways in locations where they cannot be impacted from the reverse direction, if they provide the anchorage needed for redirection of an impacting vehicle.

Guardrail end treatments shall be periodically adjusted for tension.

Reason for policy:

  • To ensure guardrail is placed in appropriate locations and installed as per current specifications

Effective Date: 6/1/99

Revision Dates:

RAP(A3) Signpost Breakaway Features

All sign posts are to be installed and maintained with breakaway features on all MoDOT maintained highways.

Reason for policy:

  • To meet FHWA standards
  • To reduce potential damages from errant vehicles striking roadside signs

Effective Date: 6/1/99

Revision Dates:

RAP(A4) Culvert Ends

See S&A(C2) Culvert Ends.

171.11.1 Protective Barrier

RAP(B1) Guardrail

Guardrail is placed at hazardous locations as a protective barrier that both restrains and redirects traffic. Requests for the placement of additional guardrail by the public should be considered on the basis of traffic safety and design criteria. All installations of guardrail must meet standard design and construction specifications.

Guardrail should not be used indiscriminately to avoid posing a greater hazard than the hazard itself. Guardrail should not be used to protect non-MoDOT property off the right of way.

Reason for policy:

  • To ensure guardrail is placed in appropriate locations and installed as per current specifications

Effective Date: 6/1/99

Revision Dates:

RAP(B2) Guard Cable

Cable and wire fabric guardrail shall be periodically adjusted for tension to assure effectiveness and to improve appearance.

Reason for policy:

  • To ensure guard cable will perform as designed

Effective Date: 6/1/99

Revision Dates:

RAP(B3) Fixed Impact Attenuators

The maintenance and repair of fixed impact attenuators requires the replacement units to be spotted in the same locations as the original modules. A detailed drawing of each installation should be available for maintenance crews performing needed repairs.

Reason for policy:

  • To assure proper operation of fixed impact attenuators

Effective Date: 6/1/99

Revision Dates:

RAP(B4) Concrete Median Barriers

Concrete median barriers shall be replaced or repaired where the damage resulted in loss of a significant piece of concrete. The type of section and extent of damage will dictate whether the section should be replaced or repaired in place.

Reason for policy:

  • To assure proper operation of barriers

Effective Date: 6/1/99

Revision Dates:

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