1.2 Design Exceptions, Design Waivers, Design Variances, Texas Highway Freeway Network Design Deviations

1.2.1 Design Exceptions

A design exception is required when the minimum values of the controlling criteria specified in this Chapter for the respective categories of construction projects are not met. A design exception is not required when values meet or exceed the minimum guidelines.
The controlling criteria for the following project categories will require a
design exception.
Minimum values requiring a design exception for each of the controlling design criteria can be found in Appendix A.
1.2.1.1 New Location and Reconstruction Projects (4R)
The adopted Federal Highway Administration (FHWA) design requirements in 23 CFR 625, and 49 CFR 37.9 apply to new location and reconstruction projects (4R) on the National Highway System (NHS).
Table 1-4
shows the list of AASHTO’s ten controlling design criteria that will require a
design exception
 when the minimum requirements specified in Appendix A are not met.
A design exception
is not
 required when values meet or exceed the minimum requirements.
Table 1-4: AASHTO's Controlling Criteria for New Location and Reconstruction Projects (4R)
Criteria
Minimum Criteria
Criteria Reference
Explanation
Design Speed
Appendix Table A-1
Section 4.2
Minimum design speed based on the functional classification.
Lane Width
Appendix Table A-2
Note 1
Minimum lane width based on functional classification, type of lane (Mainlane, etc.) and design speed.
Shoulder Width
Appendix Table A-3
Note 2
Minimum outside and inside shoulder widths based on functional classification, type of facility and design speed.
Horizontal Curve Radius
Appendix Table A-4
Section 4.7.2
Minimum horizontal curve radius based on design speed and maximum superelevation rate.
Superelevation Rate
Table 4-4 through Table 4-7
Section 4.7.3
The amount of cross slope needed on a horizontal curve to help counterbalance the centrifugal force of a vehicle traversing the curve based on the design speed.
Stopping Sight Distance (SSD)
3
Appendix Table A-5
Section 4.11.1
The minimum distance a driver needs to be able to see in order to have room to stop before colliding with something in the roadway. Use k-values to assist calculation.
Maximum Grade
Appendix Table A-6
Section 4.8.1
Maximum gradient of a roadway along the centerline. For maximum grade for ramps see Table 15-2.
Cross Slope
Appendix Table A-7
Section 4.10.4
Maximum transverse slope across a pavement surface, excluding superelevation.
Vertical Clearance
Appendix Table A-8
Section 4.8.6
Minimum specified height of a bridge or overhead projection above the roadway.
Design Loading Structural Capacity
Appendix Table A-9
TxDOT Bridge Design Manual - LRFD
The Design Load Structural Capacity-Maximum Load that a bridge is designed to handle.
Notes:
  1. For Local Roads see Section 5.1.6; for Collectors see Section 6.1.6; for Arterials see Section 7.1.6; for Freeways see Sections 8.1.6; for Mobility Corridors see Section 9.2.2.
  2. For Local Roads see Section 5.1.7; for Collectors see Section 6.1.7; for Arterials see Section 7.1.7; for Freeways see Sections 8.1.7; for Mobility Corridors see Section 9.2.3.
  3. SSD applies to horizontal alignments and crest vertical curves for the purposes of a Design Exception. SSD for crest vertical curves is a direct correlation with the K-Value. If the minimum K-Value is satisfied for a crest vertical curve (Figure 4-6), then the vertical SSD is satisfied under usual conditions.
TxDOT implements additional controlling criteria for design elements that will require a
design exception
 if the conditions are not met on new location and reconstruction projects (4R).
Table 1-5
shows the list of TxDOT’s additional controlling criteria for new location and reconstruction projects that will require a
design exception
 when the minimum requirements are not met.
A design exception
is not
 required when values meet or exceed the minimum requirements.
Table 1-5: TxDOT's Controlling Criteria for New Location and Reconstruction Projects (4R)
Criteria
Minimum Criteria
Criteria Reference
Explanation
Bridge Class Culvert Protection
Appendix Table A-10
TxDOT Bridge Railing Manual
All ADTs
Bridge Rail
Appendix Table A-11
TxDOT Bridge Railing Manual
Bridge rail must comply with MASH and meet requirements of the TxDOT Bridge Railing Manual.
1.2.1.2 Resurfacing, Restoration or Rehabilitation Projects (3R)
TxDOT implements
controlling criteria
 for the following design elements that will require a
design exception
 if the minimum conditions are not met on resurfacing, restoration, or rehabilitation projects (3R).
Table 1-6
shows the list of TxDOT’s additional controlling criteria that will require a
design exception
 when the minimum requirements are not met.
A design exception
is not
 required when values meet or exceed the minimum requirements.
For 3R projects, “high-volume” roadways are those with greater than or equal to a current ADT of 1,500.
“Low-volume” roadways are defined as those with a current ADT of less than 1,500.
Table 1-6: TxDOT’s Controlling Criteria for Resurfacing, Restoration or Rehabilitation Projects (3R)
Criteria
High Volume ≥ 1500 ADT
Low Volume < 1500 ADT
Minimum Criteria
Criteria Reference
Explanation
Design Speed
X
Appendix Table A-12
Section 10.1.5.2
Minimum design speed based on the highway class and context.
Lane Width
X
X
Appendix Table A-13
Section 10.1.5.4
Minimum lane width based on the respective functional classification, context classification, and current Average Daily Traffic.
Shoulder Width
X
X
Appendix Table A-14
Section 10.1.5.4
Minimum shoulder width based on the respective functional classification, context classification, and current Average Daily Traffic.
Horizontal Curve Radius
X
Appendix Table A-15
Section 10.1.5.1
Minimum horizontal curve radius based on design speed and maximum superelevation rate.
Superelevation Rate
X
Table 4-4 through Table 4-7
Section 10.1.5.1
The amount of cross slope needed on a horizontal curve to help counterbalance the centrifugal force of a vehicle traversing the curve based on the design speed.
Stopping Sight Distance (SSD)
3
X
Appendix Table A-16
Section 4.11.1
The minimum distance a vehicle needs to be able to see to have room to stop before colliding with something in the roadway. Use K-values to assist calculation.
Maximum Grade
X
Appendix Table A-17
Section 4.8.1
Maximum gradient of a roadway along the centerline.
Design Loading Structural Capacity
X
X
Appendix Table A-18
TxDOT Bridge Design Manual - LRFD
The Design Load Structural Capacity-Maximum Load that a bridge is designed to handle.
Bridge Class Culvert Protection
X
Appendix Table A-19
TxDOT Bridge Railing Manual
All ADTs
Deficient Bridge Rail
X
Appendix Table A-20
TxDOT Bridge Railing Manual
Minimum requirements are met for new bridge rail or existing rail to remain in place.
Notes:
  1. SSD applies to horizontal alignments and crest vertical curves for the purposes of a Design Exception for 3R high-volume roadways. SSD for crest vertical curves is a direct correlation with the K-Value. If the minimum K-Value is satisfied for a crest vertical curve (Figure 4-6), then the vertical SSD is satisfied under usual conditions.
1.2.1.3 Resurfacing or Restoration Projects (2R)
Design exceptions
 are required for 2R projects anytime the existing geometric or bridge features for the proposed project will be reduced below design standards.
A design exception
is not
 required when values meet or exceed the minimum requirements.
1.2.1.4 Bicycle Facilities
Table 1-7
gives the controlling criteria for bicycle facility projects that will require
a design exception
 when the minimum requirements are not met.
A design exception
is not
 required when values meet or exceed the minimum requirements.
See
Section 18.1.7
for additional information on design exceptions for bicycle facilities.
Table 1-7: Controlling Criteria for Bicycle Facilities
Criteria
Minimum Criteria
Criteria Reference
Explanation
Bike Lane Width
Appendix Table A-21
Section 18.4.4.2
Minimum bike lane width requirement based on context classification.
Bike Shared Lane Width (Wide Outside Lane)
Appendix Table A-22
Section 18.4.7.2
Minimum lane width requirement based on context classification.
Bridge Deck Clear Space
Appendix Table A-23
Note 1
Minimum shoulder and offset measured to the toe of barrier provided on the structure.
Notes:
  1. For Local Roads see Section 5.1.7; for Collectors see Section 6.1.7; for Arterials see Section 7.1.7.
1.2.1.5 Special Facilities
Table 1-8
gives the requirements for off-system bridge replacement and rehabilitation projects with current ADT of 400 or less that will require a
design exception
 when the minimum requirements are not met.
A design exception
is not
 required when values meet or exceed the minimum requirements.
If the current ADT is greater than 400, then applicable 4R or 3R criteria applies.
Table 1-8: TxDOT’s Controlling Criteria for Off-System Bridges with ≤ 400 ADT
Criteria
Minimum Criteria
Criteria Reference
Explanation
Design Speed
Appendix Table A-24
Section 12.2.2
Minimum design speed based on condition of the remainder of the road.
Stopping Sight Distance (SSD)
1
Minimum SSD to be attained based on the condition of the remainder of the road.
Horizontal Curve Radius
Minimum horizontal radius based on design speed and the condition of the remainder of the road.
Superelevation Rate
Minimum superelevation to be used based on the condition of the remainder of the road
Maximum Grades
Maximum grade to be used based on the condition of the remainder of the road.
Minimum Structure Width
Minimum width measured between face to face of rail depending on approach roadway width.
Bridge End Guard Fence
Minimum length of transition and end treatment use.
Approach Roadway Width
Minimum approach width, transition, and surfacing.
Design Loading Structural Capacity
The Design Load Structural Capacity-Maximum Load that a bridge is designed to handle.
Traffic Control
Traffic control for detours and placement of traffic control devices.
Notes:
  1. Stopping Sight Distance (SSD) applies to horizontal alignments and crest vertical curves for the purposes of a Design Exception. SSD for crest vertical curves is a direct correlation with the K-value. If the minimum K-Value is satisfied for a crest vertical curve (Figure 4-6), then the vertical SSD is satisfied under usual conditions.
1.2.1.6 Off-System Historically Significant Bridge Projects
Table 1-9
gives the controlling criteria for off-system historically significant bridge projects that will require a
design exception
 when the minimum requirements are not met.
A design exception
is not
 required when values meet or exceed the minimum requirements.
Table 1-9: TxDOT’s Controlling Criteria for Off-System Historically Significant Bridges
Criteria
ADT
Minimum Criteria
Criteria Reference
Explanation
Roadway Width
≤ 400
Appendix Table A-25
Section 12.3
Minimum roadway width based on the condition of the remainder of the road.
Load Carrying Capacity (Operating Rating)
Operating Rating, the maximum permissible live load that can be placed on the bridge. This load rating also includes the same load in multiple lanes. Allowing unlimited usage at the Operating Rating level will reduce the life of the bridge.
1.2.1.7 Park Road Projects
Design exceptions
 are not applicable to park road projects that are off the state highway system and designated as Park and Wildlife Roads (PW). Design is based on the criteria and guidance given in the current publication of the
Texas Parks and Wildlife Department Design Standards for Roads and Parking
, or as approved by the Texas Parks and Wildlife Department (TPWD).
On-system park road projects, designated as Park Roads (PR), must meet the required design criteria for the appropriate roadway classification including
design exception
 or
design waiver
 requirements.
A design exception or design waiver
is not
 required when values meet or exceed the minimum requirements.
A Design Exception form and other information can be found on the Design Division’s website (TxDOT intranet only).

1.2.2 Design Waivers

When criteria are not met for non-controlling design elements, a design exception is not required. However, a departure from the minimum criteria outlined in the RDM will be handled by
design waivers
 at the District level. Design waivers will be granted as the District authorizes. A design waiver is not required when values meet or exceed the minimum requirements.
TxDOT’s non-controlling criteria for the following project categories will require a
design waiver
.
Minimum values requiring a design waiver for each of the non-controlling design criteria can be found in Appendix B.
1.2.2.1 New Location and Reconstruction Projects (4R)
Table 1-10
gives TxDOT’s non-controlling criteria for 4R projects that will require a
design waiver
 when the minimum requirements are not met. A design waiver
is not
 required when values meet or exceed the minimum requirements.
Table 1-10: TxDOT Non-Controlling Criteria for 4R Projects
Criteria
Minimum Criteria
Criteria Reference
Explanation
Curb Parking Lane Width
Appendix Table B-1
Section 4.10.16
Minimum width required for vehicles to park on the edge of the roadway in urban and suburban areas based on the functional class of the roadway.
Speed Change Lane Width
Appendix Table B-2
Section 4.10.2 and 8.1.8
Minimum width of acceleration or deceleration lanes for left or right turns, exit or entrance lanes, or a climbing lane based on the highway class.
Length of Speed Change Lanes
Appendix Table B-3
Section 4.10.2
Minimum length of acceleration or deceleration lanes for left or right turns, exit or entrance lanes, or a climbing lane based on the highway class.
Curb Offset
Appendix Table B-4
Section 4.10.12
Minimum distance between the edge of the travel lane and the face of the curb.
Bridge Width
Appendix Table B-5
TxDOT Bridge Project Development Manual
Minimum overall bridge width.
Median Width
Appendix Table B-6
Section 4.10.15
Minimum width of separation between dual roadways which separates the traffic flow in the opposite direction.
Clear Zone
Appendix Table B-7
Section 4.10.7
The minimum unobstructed, traversable area provided beyond the edge of the through traveled way for the recovery of errant vehicles.
Lateral Offset to Obstructions
Appendix Table B-8
Section 4.10.8
Minimum distance from the edge of the traveled way, beyond which a roadside object will not be perceived as an obstacle and result in a motorist’s reducing speed or changing vehicle position on the roadway
Railroad Overpass Geometrics
Appendix Table B-9
TxDOT Bridge Project Development Manual
Minimum vertical and horizontal clearances.
Sag Vertical Curve Length
1
Appendix Table B-10
Section 4.8.2
Length of sag vertical curve.
Superelevation (Non-rate elements)
Appendix Table B-11
Sections 4.7.6 and 4.7.7
Non-rate elements include length and location of superelevation transitions.
Guardrail Length
Appendix Table B-12
Section 17.3
The Length of Need (LON) of guardrail required to protect both adjacent and opposing traffic, except where access accommodation is needed.
Shared Use Path Width
Appendix Table B-13
Section 18.4.1
Minimum width for Bikeways that are separated from vehicular traffic that also allow pedestrians and non-motorized users.
Separated Bike Lane/ Buffered Bike Lane Width
Appendix Table B-13
Sections 18.4.2 and 18.4.3
Minimum width for Bikeways that are separated from vehicular traffic by vertical elements or striped buffer areas in the street
Bike Accessible Shoulder Width
Appendix Table B-13
Section 18.4.6
Minimum width for Bikeways on a roadway adjacent to vehicle traffic.
Notes:
  1. Sag Vertical Curve Length applies to sag vertical curves for the purposes of a 4R Design Waiver. Sag Vertical Curve Length for vertical alignment is a direct correlation with the K-Value. If the minimum K-value is satisfied for a sag vertical curve (Figure 4- 7), then the Sag Vertical Curve Length is satisfied under usual conditions. For minimum Sag Vertical Curve Lengths at UnderCrossings, see Figure 4-29. See Section 4.8.2 for additional guidance on comfort criteria.
1.2.2.2 Resurfacing, Restoration or Rehabilitation Projects (3R)
Table 1-11
gives TXDOT’s non-controlling criteria for 3R projects that will require a
design waiver
 when the minimum requirements are not met.
A design waiver
is not
 required when values meet or exceed the minimum requirements.
Table 1-11: TxDOT’s Non-Controlling Criteria for Resurfacing, Restoration or Rehabilitation Projects (3R)
Criteria
High Volume ≥ 1500 ADT
Low Volume < 1500 ADT
Minimum Criteria
Criteria Reference
Explanation
Design Speed
X
Appendix Table B-14
Section 10.1.5.2
Minimum design speed based on the functional classification.
Horizontal Curve Radius
X
Appendix Table B-15
Section 10.1.5.1
Minimum horizontal curve radius based on design speed and maximum superelevation rate.
Superelevation Rate
X
Table 4-4 through Table 4-7
Section 10.1.5.1
The amount of cross slope needed on a horizontal curve to help counterbalance the centrifugal force of a vehicle traversing the curve based on the design speed.
Stopping Sight Distance (SSD)
1
X
Appendix Table B-16
Section 4.11.1
Minimum SSD to be attained based on a vehicle’s ability to stop before reaching a stationary object in its path, at a certain design speed.
Maximum Grade
X
Appendix Table B-17
Section 4.8.1
Maximum gradient of a roadway along the centerline.
Superelevation (Non-rate elements)
X
X
Appendix Table B-18
Sections 4.7.6 and 4.7.7
Non-rate elements include length and location of superelevation transitions
Bridge Width
X
X
Appendix Table B-19
TxDOT Bridge Project Development Manual
Minimum overall bridge width.
Deficient Bridge Rail
X
Appendix Table B-20
TxDOT Bridge Railing Manual
Minimum requirements are met for new bridge rail or existing rail to remain in place.
Clear Zone
X
X
Appendix Table B-21
Section 4.10.7
The minimum unobstructed, traversable area provided beyond the edge of the through traveled way for the recovery of errant vehicles.
Speed Change Lane Width
X
X
Appendix Table B-22
Section 4.10.2
Minimum width of acceleration or deceleration lanes for left or right turns, exits or entrance lanes, or a climbing lane based on the highway class.
Length of Speed Change Lanes
X
X
Appendix Table B-23
Section 4.10.2
Minimum length of acceleration or deceleration lanes for left or right turns, exit or entrance lanes, or a climbing lane based on the highway class.
Curbside Parking Lane Width
X
X
Appendix Table B-24
Section 4.10.16
Minimum width of parallel parking lanes based on the functional class of the roadway.
Guardrail Length
X
X
Appendix Table B-25
Section 17.6
The Length of Need (LON) of guardrail required to protect adjacent and opposing traffic, except where access accommodation is needed.
Sag Vertical Curve Length
2
X
X
Appendix Table B-26
Section 4.8.2
Length of sag vertical curve.
Notes:
  1. SSD only applies to crest vertical curves for the purposes of a Design Waiver for 3R low-volume roadways. SSD for crest vertical curves is a direct correlation with the k-value. If the minimum k-value is satisfied for a crest vertical curve (Figure 4-6), then the vertical SSD is satisfied under usual conditions.
  2. Sag Vertical Curve Length applies to sag vertical curves for the purposes of a 3R Design Waiver. Sag Vertical Curve Length for vertical alignment is a direct correlation with the K-Value. If the minimum K-value is satisfied for a sag vertical curve (Figure 4-7), then the Sag Vertical Curve Length is satisfied under usual conditions. For minimum Sag Vertical Curve Lengths at Under-Crossings, see Figure 4- 29. See Section 4.8.2 for additional guidance on comfort criteria.
1.2.2.3 Resurfacing or Restoration Projects (2R)
Design waivers are not applicable to 2R projects.
1.2.2.4 Bicycle Facilities
Table 1-12
gives TxDOT’s non-controlling criteria for bicycle facility projects that will require a
design waiver
 when the minimum requirements given in
Chapter 18
cannot be met.
A design waiver
is not
 required when values meet or exceed the minimum requirements.
Table 1-12: TxDOT’s Non-Controlling Criteria for Bicycle Facilities
Criteria
Minimum Criteria
Criteria Reference
Explanation
Shared Use Path Width
Appendix Table B-13
Section 18.4.1
Minimum requirements based on context classification.
Separated Bike Lane/Buffered Bike Lane Width
Appendix Table B-13
Sections 18.4.2 and 18.4.3
Minimum requirements based on context classification.
Bike Accessible Shoulder Width
Appendix Table B-13
Section 18.4.6
Minimum requirements based on context classification.
1.2.2.5 Special Facilities
Table 1-13
gives TxDOT’s non-controlling criteria for off-system bridge replacement and rehabilitation projects with current ADT of 400 or less that will require a
design waiver
 when the minimum requirements are not met.
A design waiver
is not
 required when values meet the minimum requirements.
Table 1-13: TxDOT’s Non-Controlling Criteria for Off-System Bridges with ≤ 400 ADT
Criteria
Minimum Criteria
Criteria Reference
Explanation
Superelevation (Non-rate elements)
Appendix Table B-11
Section 12.2.2
Non-rate elements include length and location of superelevation transitions.
Sag Vertical Curve Length
1
Appendix Table B-10
Section 12.2.2
Length of sag vertical curve.
Bridge Width
Appendix Table B-5
Section 12.2.2
Minimum overall bridge width.
Notes:
  1. Sag Vertical Curve Length applies to sag vertical curves for the purposes of a 3R Design Waiver. Sag Vertical Curve Length for vertical alignment is a direct correlation with the k-value. If the minimum k-value is satisfied for a sag vertical curve (Figure 4- 7), then the Sag Vertical Curve Length is satisfied under usual conditions. For minimum Sag Vertical Curve Lengths at Under-Crossings, see Figure 4-29. See Section 4.8.2 for additional guidance on comfort criteria.
1.2.2.6 Off-System Historically Significant Bridge Projects
Design waivers
 are not applicable to off-system historically significant bridge projects.
1.2.2.7 Park Road Projects
Design waivers
 are not applicable to off-system park road projects. On-system Park Road projects need to meet the applicable criteria.
A Design Waiver form and other information can be found on the Design Division’s website (TxDOT intranet only).

1.2.3 Design Variances for Pedestrian Facilities

A
design variance
 is required to be sent to the Texas Department of Licensing and Regulation (TDLR) whenever the design guidelines specified in the
Texas Accessibility Standards (TAS)
and
Accessibility Guidelines for Pedestrian Facilities in the Public Right-of-way (PROWAG)
are not met. Design variances should be sent to the Design Division – Landscape Architecture Branch for review prior to being submitted to TDLR for approval. See Chapter 19 for additional discussion on pedestrian facilities. This documentation should be kept in the project files.
A Design Variance form and other information can be found on the Design Division’s website (Landscape Architecture Branch) (TxDOT intranet only).

1.2.4 Texas Highway Freight Network (THFN) Design Deviations

A Texas Highway Freight Network (THFN)
design deviation
 is required for projects that do not meet specified Bridge Vertical Clearance Requirements; see
Sections 4.8.6
and
21.2
for applicable project criteria, and Table 4-13 for vertical clearance values.
The Deviation request is exclusive of (and if applicable in addition to) the design exception that may be needed for vertical clearances not meeting the specified requirements in
Sections 4.8.6
. of the respective roadway facility.
The THFN Deviation requests must be submitted to the Design Division (DES) – Project Delivery Section and will be reviewed by an assigned Design Deviation Committee.
A THFN Design Deviation form, process flowchart, and other information can be found on the Design Division’s website.

1.2.5 Approval Process

1.2.5.1 Design Exceptions
The review of design exceptions and recommendations for approval/non-approval may be established individually by each TxDOT District. For example, a four-person review committee might be established which would include:
  • Director of Transportation Planning and Development;
  • Director of Construction;
  • Director of Operations/Traffic; and
  • Area Engineer (not responsible for project management).
The recommendation of approval/non-approval by a majority of the committee members constitutes a quorum for recommending signature action. Since the construction plans are sealed, the design exception documentation does not require an engineer’s seal.
As per the current
Stewardship and Oversight Agreement on Project Assumption and Program Oversight by and Between Federal Highway Administration, Texas Division Office, and the Texas Department of Transportation (TxDOT)
, delegation of review and approval of design exceptions on the Interstate Highway System has been assigned to TxDOT. Additionally, if a project (Interstate or other) is identified on the FHWA Texas Division’s list of “Involved Projects” (TxDIP), and the project’s TxDIP Stewardship and Oversight (S&O) plan identifies specific design exception approval responsibility to FHWA, then design exceptions proposed for that project will be required to be submitted to FHWA for approval. All design exceptions must be signed by the
TxDOT District Engineer
 and this signature authority cannot be delegated.
Design exceptions must be documented on the PS&E Transmittal Data Form 1002.
Table 1-14
lists the Design Exception Approval Authority. The final signed Form 1002 all design exception forms and related documentation should be filed in ProjectWise and permanently retained.
For design exceptions on Interstates, refer to the
Design Exception Request for Interstate Highways TxDOT Standard Operating Procedures
found on the DES-PDS webpage.
Table 1-14: Design Exception Required Approvals
Project Type
Approval Authority
Submit Form To
State oversight projects
TxDOT District Engineer
District TP&D
Federal oversight projects
TxDOT District Engineer
District TP&D
Interstate projects
1
TxDOT DES
DES – Project Delivery Section
“Involved projects” (TxDIP)
Based on TxDIP S&O plan
DES – Project Delivery Section
Design Loading Structural Capacity or Bridge Railing, or Bridge Class Culvert protection
Bridge Division (BRG)
BRG - Design Section
Notes:
  1. Vertical clearance of < 16-ft on Interstate highways requires additional coordination and approval from the Department of Defense.
1.2.5.2 Design Waivers and ADA Design Variances
1.2.5.2.1 Design Waivers
Design waivers will be granted as the District authorizes. Complete documentation should be retained permanently in the District project files.
1.2.5.2.2 ADA Design Variance
An Americans with Disabilities Act (ADA) Design Variance form, process flowchart, and other information can be found on the
Design Division’s (Landscape Architecture Branch) website
.
1.2.5.3 Texas Highway Freight Network (THFN) Design Deviation
A THFN Design Deviation form, process flowchart, and other information can be found on the Design Division’s website (Project Delivery Section).
Table 1-15
lists the approval authority for design waivers, design variances, and design deviations.
Table 1-15: Approval Authority for Design Waivers, Design Variances, and Design Deviations
Type
Approval Authority
Submit Form To
Design Waiver
TxDOT District
District TP&D
ADA Design Variance
TDLR
DES – Landscape Architecture Branch
THFN Design Deviation
DES
DES – Project Delivery Section