10.1.1 Introduction
Rehabilitation (3R) projects consist of transportation projects that extend the service life and enhance the safety of a roadway. In addition to resurfacing and restoration, the activities may include upgrading the geometric design and safety of the facility. Work on 3R projects does not include the addition of through travel lanes (i.e., no added capacity). 3R projects may include upgrading geometric features such as roadway widening, minor horizontal realignment, and bridge improvements to meet current standards for structural loading and accommodate the approach roadway width. See
for additional clarification on horizontal and vertical alignment.
Design guidelines for 3R projects have been developed to allow for greater design flexibility.
At the District’s option, design values above those presented in this chapter may be used.
3R design decisions should be based on an assessment of the safety and traffic operational performance of the existing road and the cost-effectiveness of potential design improvements. Geometric design improvements should be considered as part of a 3R project in the following situations:
- An analysis of the crash history of the existing road identifies one or more crash patterns that are potentially correctable by a specific design improvement;
- An analysis of the traffic operational level of service (LOS) indicates that the LOS is currently lower than the target LOS for the facility or will become lower than the target LOS within the service life of the planned pavement resurfacing (typically 7 to 12 years); or
- A design improvement would reduce sufficient crashes over its service life to be cost effective (i.e., the anticipated crash reduction benefits over the service life of the project exceed the improvement implementation cost).
With a few exceptions (e.g., see bicycle accommodations below), in the absence of any of the three situations defined above, there is no indication that a design improvement is needed as part of a 3R project, and the existing roadway and roadside geometric features should remain in place. Design or traffic control improvements, in addition to pavement resurfacing, should be considered where anticipated benefits exceed anticipated costs.
For Benefit cost evaluations for 3R projects, spreadsheet tools and methods such as those identified in the
, or Tools 1 and 2 from
may be used to assess both single design alternatives and comparing several alternatives or combinations of alternatives. These tools generate both a Benefit/Cost (B/C) ratio (including safety benefits) as well as the net present value of benefits. Generally, B/C ratios of 2.0 or higher would represent a significant benefit; B/C ratios of between 2.0 and 1.0 although considered positive; additional sensitivity analyses should be done to determine whether or not the identified upgrades are sufficiently beneficial for the project and TxDOT. B/C values below 1.0 should generally not be considered.
These analyses would serve as the basis for determining whether or not specific upgrades should be made. These analyses would also serve as the basis in the justification for any needed design exceptions or design waivers (if established minimums are not met or not intended to be met) if the Benefit cost analysis indicates that such an improvement to the respective minimum values is not warranted.
These guidelines offer sufficient flexibility to allow cost-effective design and further compliance with the program goals of preserving and extending the service life and enhancing safety. While highway safety may not be the primary reason for initiating a 3R project, it is an essential element of all projects. 3R projects should identify and incorporate appropriate safety enhancements.
For 3R projects, current average daily traffic (ADT) volumes of less than 1,500 are defined as low traffic volume roadways.
3R Projects must be assessed to determine if bicycle accommodations are required per Chapter 18
If bicycle facilities are provided, see
for requirements.