4.10.8 Lateral Offset
Lateral offset is the 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.
It is generally preferable that there be uniform clearance between traffic and roadside features such as bridge railings, parapets, retaining walls, and roadside barriers. In an urban environment, ROW is often limited and is characterized by sidewalks, enclosed drainage, numerous fixed objects (e.g., signs, utility poles, luminaire supports, fire hydrants, sidewalk furniture, etc.), and traffic making frequent stops.
Uniform alignment enhances highway safety by providing the driver with a certain level of expectation, thus reducing driver concern for and reaction to those objects.
The lateral offset to obstructions helps to:
- Avoid impacts on vehicle lane position and encroachments into opposing or adjacent lanes;
- Improve driveway and horizontal sight distances;
- Reduce the travel lane encroachments from occasional parked and disabled vehicles;
- Improve travel lane capacity; and
- Minimize contact from vehicle mounted intrusions (e.g., large mirrors, car doors, and the over-hang of turning trucks).
Where a curb is present, the lateral offset is measured from the face of curb (FOC) and must be a minimum of 1.5-ft. A minimum of 1-ft lateral offset should be provided from the toe of barrier to the edge of traveled way.
See
for an illustration of lateral offset minimums.
Figure 4-18: Lateral Offset Minimums
A guard fence placed in the vicinity of a curb per the current TxDOT guardrail standard does not violate the minimum lateral offset requirements.