A significant aspect of wall design from an aesthetic standpoint is the contrast of the horizontal line with the ground plan and alignment of the wall with other elements near or behind it. The extended form of walls is viewed linearly, with the wall top creating a distinct contrast to background elements. Since walls are viewed with the rest of the world as their background, the appearance of wall elements should be considered carefully:

Since walls are strong vertical elements, they can dominate the field of view. The color, texture, and pattern have a commanding influence on driver perception of the highway landscape. The opposite side of the wall must be considered as well and designed with the impact to adjacent properties in mind (see ).

The size of the roadway creates a relationship between color, texture, pattern, and scale that should be noted. To be appreciated, a color, pattern, or texture must be visible. The size of treated areas should not be so small as to have little visual effect. Inversely, too much of a single treatment can become boring or overpowering. There are no hard-and-fast rules to determine when these lines have been crossed but in general, special treatments should accent rather than dominate a landscape scene.

Depending upon the color, texture, and pattern selected, the wall will either blend or contrast with the background landscape. Always reference back to the LAMP (see ) to ensure that selections are in keeping with the overall vision for the corridor (see ).

Along the highway side, wall colors should be selected to blend and complement the natural surroundings. When adjacent to residential neighborhoods, colors should be muted so that they do not conflict with the appearance of the residences (see and ).

Textures are most visually effective where traffic speeds are slower (controlled intersections) or where structures are close to the travel lane. Textures should be rougher if they are to be seen from longer distances. Rougher textures create more shadows on their surfaces and so create a high contrast with the sunlit areas of the surface, thereby providing a more visually prominent surface.

Textures on concrete may be achieved using form-liners, sandblasting, or washing to expose the integral aggregate. The malleability of concrete allows unique patterns to be included in the design at a reasonable cost (see and ).

Special finish options for vertical surfaces include:

Common form liner patterns include raised or indented vertical patterns as well as brick and stone. Strong vertically oriented textures will emphasize the height of structures while horizontal textures will de-emphasize height and highlight the structure’s linear character.

Pattern choices should complement the wall surroundings. A heavily developed urban area may suggest a formal architectural pattern, while rural areas or locations with prominent natural features may warrant the use of form liner patterns suggestive of local native materials (see ).

Sandblasting may be used as a relatively inexpensive method of adding a softer textural interest. These textures will not be visible at long distances since sandblasting only affects a shallow depth of the surface. Consequently, this technique is best used where traffic speeds are lower, and the walls are near the travel lane.

Sandblasting entire surfaces may make the walls less distinct and blend into the background. A band of untreated surface at the edges of the wall will prevent this and make the texture contrast more visually effective.

Pigmented coatings are a relatively inexpensive method of adding visual interest to structures. Paints have proven to be less durable than stains, requiring reapplication due to flaking, and are not recommended for concrete structures. Paints also fade significantly over time, so the use of darker color paints should be considered if painting is desired. Acrylic stains have proven to be much more long-lived in concrete applications and are available in a wide range of colors.

Stains are affected by the quality of the surface before application. Surface imperfections due to damage or to inadequate vibration during pouring will be clearly visible once the stain is applied.

To deter/minimize the impact of vandalism on hard surface improvements in the ROW and its other facilities, TxDOT encourages the use of anti-graffiti coating products in its projects. These coatings may be either Type II (Solvent-Cleanable) or Type III (Water-Cleanable). Care should be taken to follow along with manufacturer’s recommendations in applying the coating. TxDOT has found that some anti-graffiti coatings have tended to stain and/or fade some original paint colors if not applied appropriately.

Integral color infuses the entire quantity of concrete used in the wall. Variation in the quality of concrete can result in different shades of color, so matching earlier pours becomes very difficult when adding new sections or repairing existing damaged areas.

Non-structural veneers of various materials may be installed over other wall structural materials. The veneers may be stone, modular concrete block, or brick, and in some cases, tile. Veneers may be useful in creating visual links between unconnected elements by retrofitting some portions of wall surfaces with the same material.

Modular units are most prominent in the use of pre-cast panel, Retained Earth Walls. A smaller unit scale is found in Modular Block retaining wall systems. These systems impart patterns to wall surfaces that provide visual interest and help prevent large surfaces from becoming oppressively monotonous.

The patterns provided by these systems can result from two components: the shape of the modular unit and the pattern created by the arrangement of different colored or textured units. The scale of the structure and the type of unit affect the decision to add pattern in this way (see ).