The report out today by the Institute of Welsh Affairs report warns that Wales is more reliant on the car than any other region or nation in the UK.
It also claims bus services in Wales are in serious long-term decline and rail serves only a very small part of the country and, whilst growing, has less than a fifth of the passenger journeys of buses.
And the report states that despite the Active Travel (Wales) Act 2013, walking and cycling levels are generally static or declining.
Given that the sale of new petrol and diesel cars is to be banned from 2040, the report says there is a clear need for managed change in Wales transport system.
It recommends that Transport for Wales prioritise the development and integration of bus services into the South Wales Metro networkand the Welsh Government impose a default 20mph limit in urban areas, allowing local authorities discretion in exempting routes where justified.
Importantly, this research sets out why and how change in the transport sector should be achieved and does so in accord with a key Welsh law, the Well-being of Future Generations (Wales) Act 2015, said report author, Chris Roberts.
The transport sector has considerable potential to address the national goals set out in that act and address pressing concerns relating to health, the economy, climate change and equality.
And the Institutes Re-energing Wales project coordinator, Shea Buckland-Jones, added:Our research shows that Wales needs a radical new approach to transport. Welsh Government are central to delivering the required change and need to show leadership in transforming Wales transport sector.
Earlier this month, Environment Journal reported that the Welsh Government is introducing 50 mph speed limits and other measures in five locations next week to improve air quality and save lives.