Welsh Government is to pause all new road-building projects to carry out a review - with the decision impacting plans like the Deeside "Red Route", the Llandeilo bypass, and a third Anglesey crossing.
Transport now comes under the Welsh Government's climate change ministry and it is putting on hold all road-building projects that have not yet started while it examines whether the money should be spent in other ways, such as public transport.
Any projects where work has begun will continue.
Deputy Climate Change Minister Lee Waters is due to announce the review in the Senedd on Tuesday afternoon.
CBI Wales said removing bottlenecks like on the border at Flintshire could help reduce emissions and support economic growth.
The Deeside "Red Route" is a plan for the A55 in Flintshire which would include a new eight mile dual carriageway.
There was opposition from people who said it would cut through ancient woodland and contribute to climate change.
The £130m third Menai crossing has been on the agenda for years with designs being looked at, although the collapse of the Wylfa Newydd nuclear project had weakened the case for the investment.
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Meanwhile, the Llandeilo bypass had already been delayed to 2025.
It's understood the freeze will not affect projects that have already begun construction such as the A465 dualling.
The Welsh Government isn't yet publishing details of the review but says it will consider "shifting spending" towards better maintaining existing roads, rather than building new ones, and look at all proposed road investments, whether funded directly by the Welsh Government or indirectly by grants.
CBI Wales director Ian Price said: “Removing bottlenecks helps traffic move more smoothly, reducing local emissions and improving the efficiency of the local economy.
"Public transport use in Flintshire is down 47%.
"As more people return to the workplace, commuters are preferring private transport. This could spell trouble for the local communities of Deeside if there is no plan to respond to these trends.
"The review should consider if there are viable alternatives for Deeside that can meet short and long-term pressures.”
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Welsh Conservative Shadow Transport Minister, Natasha Asghar MS said: “At such a delicate economic time, this decision could prove a significant blow for our recovery.
“Many roads across Wales are not fit for purpose and have had a damaging impact on our economic fortunes, environment and public safety. Regular traffic jams deter investment and have contributed to Wales having some of the worst air quality in the 海角视频.
“Ministers seem hell-bent on letting our roads deteriorate and forcing everyone onto public transport, despite major doubts over the ability of the network in Wales to cope after years of poor management and under-investment by Labour.
“Welsh workers and businesses urgently require more information about the scope of the review and the Welsh Labour Government’s long-term intentions for our transport infrastructure.”
Sophie Howe, Future Generations Commissioner for Wales, said: "This is a huge step in the right direction for the healthier, resilient and more equal Wales and shows the difference having a Well-being of Future Generations Act makes.
“I’m pleased that Welsh Government has responded to the recommendations in my Future Generations Report 2020 to stop prioritising investment in building new roads and move away from traditional transport planning and onto a combination of alternative solutions to the climate emergency.
“Transport is Wales' third-largest source of the gases driving climate change and heart disease is the leading cause of death in Wales - a condition linked to both poor air quality and reduced exercise."