The Grays transportation network will be massively expanded as work on a two-way system on Orsett Road begins.
Construction has begun between the intersection of Derby Road and Stanley Road.
The Crown Road, which was recently upgraded to a two-way system as part of the program, can be used as an alternative route while working.
The changes stem from feedback from residents and businesses who have expressed concerns about the city center's existing one-way system.
The initiative is part of a wider traffic strategy aimed at making the city safer and more accessible.
It should also promote job creation and give residents access to new skills.
Expected to be completed next spring, the completion of the Orsett Road two-way system will install a real-time traffic management system.
It is positioned at the intersections of Derby Road and Clarence Road, Stanley Road and Clarence Road, Stanley Road and Orsett Road, as well as Orsett Road and Derby Road.
Until then, temporary pedestrian and traffic management devices will be implemented during work and existing traffic lights will be replaced by temporary ones.
Work on the new roads will cease at Christmas before resuming in the new year.
Thurrock Council chairman Rob Gledhill said: "Grays is an important city that plays a key role in the district's economy, and this section of the road network is critical to free movement and improved access to and through the city Center.
"Every effort is made to minimize the inconvenience, including interrupting work for the Remembrance weekend and for five weeks at the end of November to avoid disruption during peak business hours."