4.5Vertical alignment#
Vertical alignment requirements typically are not reported as creating significant constraints on the potential road alignment for temporary roads.
4.5.1National / International guidance – literature review#
The following guidance from the USA relating to vertical alignment may be applicable to temporary road alignments. The vertical alignment design parameters that are discussed in the context of temporary road design include:
- Grades greater than maximums applying to the permanent alignment may be appropriate for short lengths within road work zones.
- Development of crest curves on the basis of sight distance criteria.
4.5.2Case Examples#
No case studies were identified where design exceptions for the vertical alignment were implemented.
4.5.3Design opportunities – Vertical Alignment#
Based on the information documented in the USA, the following vertical alignment elements may be considered for temporary roadways:
- Grades greater than maximums applying to the permanent alignment may be appropriate for short lengths within road work zones.
- Development of crest curves on the basis of sight distance criteria.
Historically, Transport and Main Roads recognised that for temporary roads sag vertical curves should be designed to at-least the comfort criterion of 0.1 g, if the context is suitable.
4.5.4Mitigating measures – vertical alignment#
No mitigating measures are recommended to address the above design exception opportunities.
