People with hidden disabilities can now apply for a blue badge parking permit under new rules ushered in by the Government.
The eligibility criteria in England has been expanded to include people who cannot walk without considerable psychological distress or risking serious harm.
Charities supporting people with disabilities have hailed the change, the biggest since the scheme was launched in the 1970s, as "life changing" for many.
The changes were first announced earlier this year but come into force from August 30.
Transport Secretary Grant Shapps said the scheme is a "lifeline" and it is his "sincere wish that these changes will improve even more people's lives."
National Autistic Society head of policy Tim Nicholls said: "We are delighted to see the new blue badge rules come into force.
"This will be a huge relief for thousands of autistic people and their families in England, many of whom are so anxious about things going wrong that they find it hard to leave the house at all.
"A blue badge can be life changing. To live up to this promise, it’s absolutely essential that council officials making decisions about blue badges understand autism and the challenges autistic people can face getting out and about."
What does the badge do and who has been able to get one in the past?
Permits for free parking have been available to people with a range of disabilities since the introduction of the scheme in the 1970s.
Depending on the location, the permits often enable holders to park free of charge in pay and display bays and for up to three hours on yellow lines.
In central London, road users with badges can avoid the congestion charge while driving in the heart of the city.
Badges are linked to individuals, not vehicles. This means they can be used by passengers with disabilities to stop at more convenient locations regardless of whether they are travelling in their own car, a hire car or a taxi.
Previous guidelines meant the badge was only available to people who claimed disability living allowance, were unable to walk 50 metres or were registered blind.
Exceptions to normal parking rules were also made for people who receive a War Pensioner's Mobility Supplement, or have had compensation from the armed forces for a permanent or substantial disability which caused difficulty walking.
Guidance also allowed people who are "unable to walk very far without experiencing very considerable difficulty" to apply for a badge. Children who rely on bulky and heavy medical equipment were also able to benefit.
Who is able to get a badge under the new rules?
Under updated guidance, the availability of blue badge permits has been extended to include people with hidden disabilities.
This includes those who cannot make journeys without risking serious harm to their health, or someone else's. It means people living with autism will now be able to apply for the badge for the first time.
Extension of the scheme will include people with non-visible conditions such as autism, dementia, Parkinson’s and arthritis.
The badge has also been offered to people who cannot travel without considerable psychological distress.
People who struggle with walking, both the physical act and the experience of walking, will also be able to apply for one of the permits.
Applications for the permits are assessed and offered at the discretion of local authorities.
What other changes are being made?
Local authorities will be given an additional £1.7 million to deal with the anticipated increased demand for blue badges.
The expanded scheme coincides with the launch of a review to help local authorities tackle fraudulent use of the badges.
The misuse of a blue badge is a criminal offence. Figures obtained by the Press Association from the Department for Transport show the majority of the 152 English councils did not pursue anyone for abusing the scheme in 2017/18.
Fifty-eight councils, one third of authorities, enforced the law on misuse of the permits.