Highways England has set out how it will spend £2.2bn between now and 2021 to improve the capacity and condition of roads in the south-east.
The investment - part of the Government's £15bn Road Investment Strategy to triple levels of spending on roads by the end of the decade - will see improvements and repairs to a number of major roads across the region.
Highways England (HE) said that work will begin on 24 new major projects between now and 2020, in addition to existing upgrades underway on the M3, A21 and M25.
The Government-owned company also said it is investing £200m in road maintenance this year alone, as it replaces or improves the condition of 18,716 metres of barriers and 7070 road lights. It will also replace 91 road signs in 2015.
HE claimed it will "keep a relentless focus on safety", as it aims for a 40% reduction in road casualties by 2020.
"Roads are key to our nation's prosperity. For too long they have suffered from under-investment," said roads minster, Andrew Jones.
Jones added: "The government has a long-term plan to secure the country's economic future. This £2.2 billion investment in the region's roads will directly benefit hard working families across the South East."
Major upgrades that will begin in the South East over the next five years include:
Developing plans for an additional Lower Thames Crossing
"These schemes will bring significant long-term benefits to road users on motorways and major A-roads in the South East, as well as to local residents and the economy as a whole," said Ken Simmonds, Highways England's major project for the south.
"The construction work will, of course, bring some disruption in the short term but we will ensure that we keep this to a minimum to keep traffic flowing," he added "When the schemes are completed, road users will experience safer, more reliable and less congested journeys."