He later produced a blood alcohol reading of about 150 milligrams of alcohol per 100 millilitres of blood - five times the youth limit of 30mg at the time.
Since the crash, the blood alcohol limit has dropped to zero for youths.
"I truly believe if the drinking age was 21 it wouldn't have happened. The kid wouldn't have had the access to the alcohol in the first place and it wouldn't be so socially acceptable to drive that drunk."
Mrs Nilson and her husband, Brett, last month sent a 2000-name petition to Parliament urging a rise in the drinking age, along with an open letter.
A decision on whether to raise the drinking age to 20 will be put to a conscience vote in Parliament next month.
The Alcohol Reform Bill passed its first and second readings with wide support last year.
Justice Minister Judith Collins said MPs would have a choice of three options - to introduce the split purchase age, to raise both the on-licence and off-licence purchase age to 20, or to retain the status quo.
"We have let the children rule the roost for too long," Mrs Nilson said.
She feels justice has been served to the teenager responsible for Shaun's death. Elliott pleaded guilty to manslaughter and was jailed for three years.
But the society which allowed a drunk 16-year-old behind the wheel now needed to be held to account.
"Society needs to stand up and say, 'Hang on, our kids are kids.' And we need to be working hand-in-hand to make the change."
Teenagers are now getting drunk younger because they have better access to alcohol. At school, everyone knows an 18-year-old who can hook them up, according to Mrs Nilson.
"The youth are proof today that they aren't managing the use of alcohol. They don't have respect for it, they are still adolescents."
Mrs Nilson said she would continue to work in schools and communities to raise awareness and to encourage parents to take more responsibility for their children's drinking.
Parents needed to know what their teenagers were drinking and where they were going, she said.
Today there will be a ceremony at Hamilton Boys' High School for the opening of a memorial garden for Shaun.
Mrs Nilson said it would be a place to reflect, remember and farewell her son one year on.
Letter from Tina and Brett Nilson
ONE YEAR LATER 28 MAY
CONSCIOUS DECISION NEEDED BY GOVERNMENT OVER ALCOHOL PURCHASE AGE
We have let the children rule the roost for too long. Twelve years have passed since Jenny Shipley ran the country when she declared 21 was too old to start being an adult and 18 would be the new age.
They are now saying if we can vote at 18 (which she introduced at the same time) or go to war at 18 we should be allowed to purchase alcohol or do whatever we choose.
At 18 we give the adolescent everything at the same time, full driving licience, career decisions, alcohol and drugs as they are now classed as fully grown adults, and us as parents have no say or control, So the youths think.
For parents it makes it a hard call, we have to introduce alcohol in a safe and controlled environment before 18 so they know what to expect and how to handle alcohol safely. At the age of 18 most are still at school and in the school yard it is easy to approach an 18 year old to obtain alcohol.
It is a scientific fact that at 18 their brains are not fully developed and will not be until their early 20s.
We have trialled this for over a generation now and it is now time to make a change.
I commend the fact that one part of the amended bill being passed will not allow our children to buy alcohol in a wholesalers (it stops some of the nation's concerns), however allowing our teens to go out into the streets intoxicated and drugged by corner dairy legal highs to let them wander in the early hours of the morning is ...
The statistics are horrendous, and the proof is in the pudding so to speak. Hey at 18 what can we do about it as parents, apart from giving your child the three basic essentials - love, shelter and warmth along with guidelines, boundaries and limitations as we did with our son, parenting is being taken away from us.
It is easy to make fake I.D.'s and makes the job of the bouncers and the night establishments very difficult to tell the difference between 15 - 18 year olds.
For some parents it is just too hard to say no. Positive parenting was also introduced at the same period. It has it's great advantages as a parenting guideline, but it also underachieves and it let the children get into control. I was a qualified community Karitane for Plunket and the whole nationwide team was in upheaval at one staff training when the age of 18 was introduced as we all pondered what our future society would be like. My son was 4 then.
In today's society you only need to watch a police programme on television to see how our teens are behaving on the streets, nightclubbing or pubbing. There are more youth crime rates, rapes; deaths, mental illnesses, depression and bullying and we are far too tolerant.
The Justice System have little to say as in the Youth Court the children are the parents responsibility, and I firmly believe if you do the man crime you do the man time, however this is not the case as in the medical system, along with youth workers and guidance councilors the child once again once 16 I believe is classed as an adult - CRAZY.
Our teens who were 18 at the time of the change celebrated with much cheer and the boy racers became the craze and those children are now 20-30 year olds. Our health bill for long term mental illnesses, drug and alcohol dependency, hospital admissions, kidney failure, prison admissions, crime etc, has been soaring through the roof for this age group alone. This is just one simple truth we could change for the next generation. These 20 - 30 year olds are now having children and they will be 18 one day.
The Government makes a conscious decision at the end of this month meaning each individual MP gets to make a conscious vote on the amendment of the purchase age of alcohol. Remember it's not the drinking age, as there is no rule on what age you can drink; it is the age one can purchase alcohol. Let's face it a 20 plus is easier to distinguish just in maturity alone.
We lost our son to a drunk driver who was only 16 and more than 5 times over the then legal limit. Our son had had only 2 drinks and was 5 weeks off 18 and even then we said it doesn't matter that you'll be 18 while you're still at school and living under our roof we will give you Love, Warmth, Shelter, Guidelines, Boundaries and Limitations, so I please ask of you, our Government of this generation, when you consciously make your decision, think of today's society and culture, and then seriously consider the future children's society and future culture.
We have trialed it and the youth are proof today that they aren't managing the use of alcohol let alone the legal and illegal drugs they just can't handle it. They don't have respect for it, They are still adolescents; their maturity grows rapidly from 18-21-24.
I would like to see this as a nation's conscious vote and not just a parliament one (perhaps the NZ Herald could take a poll on it).
After all, the parliament must see the benefits to both sides, alcohol and smoke taxes bring in money and I guess employment, but for what cost the nation a lot more in health, police, court systems, counseling and community funding alone.
The Government cannot justify by saying what about the teens that can purchase alcohol now as it's not fair to stop them - work out a system where if you are 18 as from 1st July 2012 you maybe served in a liquor establishment other than bottle stores or supermarkets, there after you need to be 20, but I would like to see 21 again. I remember in my time we tried to purchase alcohol and tried to get into pubs, but it was very hard to find acceptance, and always had to have someone over 21 to look after you.
That was 20 years ago, however it was hardly unheard of to have 14, 15, 16, 17, year olds drunk and disorderly let alone driving drunk.
18 - 21 was a different story as our generations parents introduced us to alcohol and adulthood we were just starting and trialing alcohol and not in full flight like the teens of today.
We also did not have the choices of alcohol as there was only beer or wine to choose from, and a hit flask if we could afford one.
Whereas the young ones of today have the lollypop premixes at 8 per cent that are so easy to drink but have a powerful kick and its supplied in box's of 24.
We are also asking our children to make adult decisions and choices while under the influence of alcohol and adults find that hard enough.
I also believe as an early child educator that parent of today need to be just that. Parents.
Monitor your children's whereabouts, guide them in knowing right from wrong, punishment (not physical) to show them boundaries, give them curfews, be firm but fair. Children need to feel loved, if you do the creativity in fun environments that doesn't involve alcohol every time, show the limitations and respect for alcohol. Combined with parents setting higher standards and the Government amending the bill we could once again be a nation of happy, healthy teens within 3 - 5 years.