The new £33m road will be officially opened by Coun Peter Box, leader of Wakefield Council and chair of the West Yorkshire Combined Authority.
It will then be open for use from 2pm.
The WERR is 7.5km long, boasts the longest single span bridge in Wakefield and the first new river crossing in Wakefield in over 100 years.
The new highway provides an essential road link between the A642 and A638. It will help to reduce congestion and pollution within the city.
The WERR is also expected to bring with it major economic benefits by unlocking the potential to develop 2,500 new homes as part of the City Fields development.
Coun Peter Box CBE, Leader of Wakefield Council, said: “I am delighted to be opening the Wakefield Eastern Relief Road. It is one of the biggest and most ambitious projects that this district has seen for decades and is a huge achievement for Wakefield.
“The new road will help reduce traffic congestion in and around the city, improve local transport links and provide access to land for future development, helping to create thousands of new jobs and supporting economic growth in our district for many years to come.
“Thank you to everyone for their patience as the work has been carried out.”
At Christmas the project team achieved one of the road’s biggest challenges, with the installation of a 1,200 tonne traffic bridge underneath the railway lines serving Wakefield Kirkgate Station, near to the Eastmoor estate.
The 56-hour round-the-clock operation was a major feat of engineering so that the railway lines could be reopened as usual following the Christmas bank holidays.
The Wakefield Eastern Relief Road is the first project constructed as part of the West Yorkshire Combined Authority’s 10-year programme of strategic transport schemes targeted to accelerate growth and create up to 20,000 jobs across the region.
Funding for the schemes is though the £1bn Leeds City Region Enterprise Partnership (LEP) Growth Deal from the Government’s Local Growth Fund.