What do losing control, speed, alcohol, drugs and inattention have in common? These are the recurring themes in crashes that have claimed, maimed and changed the lives of people travelling on New Zealand's roads.
They are also, according to experts, all the result of decisions that drivers, passengers and road users have made and have had deadly consequences.
The Christmas road toll period is one of the most studied - and feared - time on New Zealand roads.
• READ MORE: New Zealand's worst Christmas road crash sites
It usually starts on Christmas Eve and finishes on the first non-public holiday day of the new year.
It is one of the busiest, if not the busiest, time of year on our roads. It is also one of the most dangerous times of year to be on New Zealand's roads.
Annually, the road toll during this time is much higher than during other periods - claiming more lives in the two weeks than are lost in entire months at other times of year.
This Herald investigation shows there were 66 fatal crashes in the past five Christmas road toll periods.
There were also 389 serious injury crashes and 1535 minor crashes.
When examining the causes of these crashes, Ministry of Transport data shows that when averaged out across the five road toll periods, losing control was the most common factor, at 39.4 per cent.
That was followed by speed (22.8 per cent), alcohol and drugs (18.6 per cent) and inattention at 18.4 per cent.
National Road Policing Manager Superintendent Steve Greally says the holiday period provides all the ingredients for crashes to occur.
"From year to year those hot spots can change, but the toll relates to the decisions people are making when they are driving vehicles on our roads.
"People are typically driving longer distances, often on unfamiliar roads, to holiday destinations, making it a period of higher crash risk.
"Crashes happen for a number of reasons, but typically it is often the same driver behaviours that cause crashes and lead to deaths and serious injuries."
Speed has been a key focus for police trying to reduce the road toll.
Since 2013, reducing speed has been at the centre of their summer road safety plans.
Every December and January, a lower speed threshold is introduced, where anyone travelling more than 4km/h over the speed limit can be issued with a fine.
"Over the summer months, we have a lower speed threshold and for very good reason. We know that people go to a lot more parties in the summer, daylight hours are longer and it's a very social time."
This is reflected in ticketing data, which shows fines rapidly increase in those months for those years.
For example, in January 134,921 speed camera fines were issued, compared with just 32,555 in February.
That pattern was similar for the previous summer, when 149,107 were issued in December 2014 and 146,623 issued in January 2015.
In the adjacent November and February months, fines were 44,389 and 31,668, respectively.
Even this - which cost speeding drivers about $18 million in speeding fines this January and December 2015 - is not enough to lower the road toll.
University of Waikato Traffic Psychologist Dr Robert Isler said the key cause of crashes was a driver's psyche.
"For me there are no dangerous roads, it's the people who are driving them that are making them dangerous.
"I have done a lot of research on wellbeing and life satisfaction and how people drive, and sometimes I say that people drive they way they live."
He believes there is correlation between the rising road toll and people being under more stress.
That could explain the clusters of serious and fatal crashes around Christchurch, he said.
"So many other people as well, have underlying issues and we need to treat the cause, not the symptom.
"When people put themselves and others at risk by driving tired, I would say that they have a psychological reason why they can't sleep - perhaps they are stressed or have something happening that doesn't give them sleep at night."
He said New Zealand's rural roads did not help matters.
"Rural roads are often a huge problem in New Zealand because often they don't have shoulders, they have ditches with poles and trees near them.
"They are very unforgiving."
New Zealand Transport Land Transport safety manager Brent Johnston said billions of dollars each year was invested into making roads safer.
These included physical infrastructure such as median barriers, rumble strips and wide shoulders, as well as on road safety enforcement, advertising, and education campaigns trying to encourage the sort of behavioural change required on our roads.
More than 90 high-risk sites on rural State Highways across 14 regions will undergo safety improvements, said Johnston.
Dr Isler said people should not take risks while on the road.
"We still need very reasonable and good drivers that don't drive tired and take risks they shouldn't and they drive too fast and distraction is huge. It's very tempting to look at your phone."
So how can we make sure people get the message?
"What we need to do is address the issues rather than symptoms. People who rate their satisfaction in life as high are much less likely to do things that could cause crashes.
"Drivers who are most at risk of crashes perhaps need to be treated to get over issues and increase their wellbeing.
"Telling them they should drive slower with more education doesn't do the trick. People know that but do it anyway. We need a much more effective way of addressing it."
"Short of wrapping cars in bubble wrap it really does come down to one thing: making a better decision when you're driving your car.
"It really is that simple. We all did it when we sat our driver's licence test. You didn't drink and drive when you went to do your test. You didn't speed. You wore your seatbelt. If you did it then, you can do it forever."
Day 1: Our holiday blackspots: A Herald investigation reveals the most dangerous places during the Christmas Holiday road toll
Day 2: What's behind the horror on our roads? A look into the factors that are causing crashes.
Day 3: Picking up the pieces: Meet the people on the front line who face grisly scenes every day to save crash victims.
Day 4:The case for a lower road toll: Experts pitch ideas they think would save lives