The Sound Transit Board of Directors last Thursday approved a project to improve RapidRide C and D routes ahead of construction of the West Seattle and Ballard Link light rail extensions, as well as amending the 2018 budget to cover the costs of a preliminary engineering phase.

The RapidRide C route runs from Westwood Village to South Lake Union, while RapideRide D runs from Crown Hill to Downtown, with stops in Ballard and Uptown.

An early project under the voter-approved ST3 measure, Sound Transit will assess how the Metro bus lines overlap with and serve the station areas for the West Seattle and Ballard Link Extensions (WSBLE) and how to move people more efficiently prior to light rail construction, when work is expected to add street congestion.

Consultant HNTB has been tapped to conduct a speed and reliability study for the project, and improvements are expected to be identified by 2024. The contract was also amended on Sept. 27 to reflect an increase to $27.45 million.

The preliminary engineering phase of the project is estimated at $2.35 million, and a $350,000 budget was applied for the rest of 2018.

RapidRide C and D lines have the third- and second-highest bus ridership in the region, according to Sound Transit.

Public outreach is expected to start in 2019.