Cal Trans officials, working with the San Diego Association of Governments (SanDag), have crafted a plan to improve mobility along the I-5 corridor from La Jolla Village Drive to Hwy 78 in Oceanside. The project, similar to the current expansion of the I-15 corridor, will use TransNet funds and will undergo environmental and community review. It could cost between $3.5 and 4.5 billion, depending on which version is chosen.