This comprises works that aim to improve the quality of service on roads with adequate remaining pavement structural life, but with an unacceptable quality of service. Improvements are normally applied to roads experiencing an unforeseen growth in traffic due to i.e. change in use of the road. These include measures of improving quality of service on existing roads such as relieving traffic congestion, road safety, road passability, etc. Improvement works are divided into the following works types:
- LEVEL OF SERVICE (L): This comprises works that retain the existing pavement structure, but increases the width in selected areas (i.e. addition of climbing lanes) throughout the length of the section to improve passability.
- CAPACITY ( C ): This comprises works that retain the existing pavement, but increases the width over the total length of the section. These include partial widening and lane addition.
- ALIGNMENT (A): This comprises works that change the road geometry for part of a section, but that retain some of the existing pavement structure. These include local geometric improvements, and intersection improvements.
- BRIDGES (B): This comprises works that retain the existing bridge, but increases the width over the total length of the bridge. It also include all work related to improve the horizontal and vertical clearances over and under the bridge.