The temporary road is designed to take pressure off local roads and ease additional traffic caused by the project.
HS2 has received criticism for delays caused getting in and out of Aylesbury due to additional traffic, pile ups seen by the temporary traffic lights set up by the construction site.
Similar frustrations of traffic build-up have been heard regarding queues in and out of Wendover.
HS2 states that the route closely follows the future rail line and is designed to carry around 400-500 vehicles every day, which will be transporting people, equipment, and materials to the sites.
The first 11 mile section of the road which is now ready, will link the major construction site at Calvert with adjoining sites in Aylesbury and Greatworth in Northamptonshire.
Mainly this initial phase will ease the burden on the roads around Edgcott and Gawcott.
Further sections, to the north and south, are expected to be completed in the coming weeks, HS2 says.
In the summer HS2 reports that there will be a major increase in the amount of earthworks activity at the sites.
HS2 will be constructing the cuttings and embankments that will carry the railway over the summer.
HS2 Ltd project client Rohan Perin said: “The completion of the first stage of the Temporary Access Road is a really important milestone as work continues to ramp up across the central section of the HS2 route.
“In rural areas it can be a major logistical challenge to get people, materials and equipment to all our sites and a headache for local road users.
"That’s why I’m looking forward to the completion of the next stages and the benefits it will bring to both the project, and the local community.”
EKFB, HS2’s main contractor is building the temporary road, alongside a team made up of Eiffage, Kier, Ferrovial Construction and BAM Nuttall.
Once construction is complete the road will be removed, with the areas alongside the line landscaped and planted with new grassland and woodland, HS2 says.