Oxfordshire County Council said it hoped to complete the design of the 1,000-space park-and-ride and transport route by next year.
The authority has said it needs to invest £3m to develop the project, which would be recouped from the Department for Transport.
The project would cost about £36m.
A council spokesman said the project would "provide a congestion-free route for public transport on the A40" approaching Oxford.
Eynsham is the proposed site of the 1,000-space park-and-ride.
Council leader Ian Hudspeth said: "The kind of improvements we are proposing will be another step change for improving journeys following the completion of the A40 Wolvercote and Cutteslowe roundabouts."
In addition, a stretch of road from Witney to Eynsham could become a dual carriageway.
The cabinet will vote on proposals to spend £3m on designing the project.
A spokesman said the funding was needed to secure £35m of investment from the Department for Transport.
The spokesman added: "The detailed design is scheduled to be completed in April 2018, following which the construction contractor will be appointed and construction works forecasted to start in September 2018."
Construction on a new bus lane and park-and-ride west of Oxford could begin in September 2018, according to the council.