FIRST-YEAR P-plate drivers will be banned from driving between midnight and 5am and prohibited from carrying more than one passenger aged 16-20.
New State Government laws will extend the amount of time drivers spend on P-plates from two to three years, increasing the minimum full-licence age from 19 to 20.
The changes will soon be put to State Parliament in a bid to cut the youth road toll. Forty young P-platers have died on the state's roads since 2009.
"Young people make up 5 per cent of our population, but account for 12 per cent of fatalities and serious injuries on our roads," Road Safety Minister Michael O'Brien said.
The curfew and the single-passenger rule will apply only to the first year on P-plates. Other measures will include:
A FINE of $317 and three demerit points for breaching the curfew.
AN EXEMPTION on the one-passenger rule for family members.
EXEMPTIONS on the curfew and one-passenger rule if an adult full-licence driver with a clean driving record is a passenger.
WORK exemptions for people who have to drive after midnight, or transport people to work, and for police and emergency workers and volunteers.
DISQUALIFIED P-platers will no longer regress to a previous licence stage when they get their licence back, because it was found to be ineffective.
Drivers who have already partially completed their P-plate period will not have it extended to three years, but will be penalised if they break the curfew or one-passenger rule.
The proposed laws are expected to pass Parliament.
Alanna Sherrah, 23, of Mt Compass, whose brother was killed by the dangerous driving of a P-plate driver, has supported the laws.
Jake McMillan and two other passengers were killed when their car hit a tree near Mt Compass in 2010.
"Jake would still be here if the laws they are proposing (restricting passengers) were in place," Mrs Sherrah said.
Director of the Centre for Automotive Safety Research at the University of Adelaide, Professor Mary Lydon, said research showed if passenger restrictions were introduced in South Australia, there would be an estimated reduction of 12-17 fatal and serious injuries per year.
"For a night-driving restriction, there would be an estimated saving of 8-12 fatal and serious injuries per year," she said.
Changes to the Graduated Licensing Scheme have undergone several drafts since they were announced in October 2011, and have been the subject of more than 1000 public submissions to the State Government.
The most unpopular measure - and one which has now been rejected - was increasing the P-plate starting age from 17 to 18.
RAA senior manager of road safety Charles Mountain said a similar effect would be achieved by increasing the P-plate system from two to three years.
"The night driving and peer influence of passengers are seen as the big issues," he said.
"It is also a big change (from two to three years) that they are subjected to another year (P3) of restricted driving in terms of blood alcohol and drug use, one passenger and the night restriction, for another 12 months.
Despite not increasing the age by law, Mr O'Brien urged parents to consider delaying the age that they approved their children seeking a licence.
"It is important to recognise that delaying the age of obtaining a provisional licence has significant safety benefits, and I ask young drivers and their parents or caregivers to consider this," he said.
Executive Director of the Youth Affairs Council of South Australia Anne Bainbridge welcomed the backdown on raising the age of eligibility for a P-plate licence, because of the effect it would have had on young workers.
But she said the changes which had been made were still unfair.
"Decreases in road injury and fatality rates are much more likely to be achieved through whole-of-community attitudinal and behavioural change, not approaches that target young people in isolation," she said.
Motor Accident Commission chief executive Jerome Maguire said he was a passionate supporter of reducing youth road trauma and death. "There is enormous scope for improvement in this area," he said.