Operation Iron Curtain, a pre-Christmas police clampdown on unsafe trucks, started with a scare last week when a heavy trailer of contaminated soil hurtled across State Highway One near Meremere.
The trailer, its load riddled with hazardous asbestos, shot across three lanes of highway and a grass median to end in a paddock after becoming unhinged from its truck.
Luckily it remained upright and nobody was injured.
That was not the case in a crash north of Taupo on Saturday, in which three people were killed when the car in which they were passengers drifted to the wrong side of SH1 and into the path of a truck in slippery conditions.
Although police say the truck driver would have been powerless to avoid the crash, commercial vehicle investigators were out in force across the northern Waikato last week on a four-day campaign to curb risks from carriers rushing with Christmas deliveries.
Senior Sergeant Lex Soepnel, head of an investigation area from the Bombay Hills to the central North Island, was assisted not only by 27 police and vehicle safety officers at five checkpoints but also by highway patrols rounding up truckies using back roads to dodge his dragnet.
The operation received strong support from police headquarters, which sent its top safety officer to the muster, given that the Waikato-Bay of Plenty encompassing the Auckland-Hamilton-Tauranga "Golden Triangle" accounted for 100 truck crashes out of 307 nationally in the year to June 30.
Twenty of the region's crashes resulted in deaths, of 51 nationally.
Although fatigue is hard to prove as a cause, Mr Soepnel is convinced it is the commonest denominator, making it a prime focus of his operation.
"Often the real underlying cause is lack of judgment, from getting tired."
He was loath to comment on how widespread the use of amphetamines is to keep long-haul drivers awake, but acknowledged it was "not uncommon" to find drug use utensils at crash scenes.
At one of two checkpoint weigh-pits outside Huntly on Wednesday morning, the young driver of a 10-tonne truck was having to cool his heels after failing to take a mandatory 10-hour break since the night before.
He received a $300 instant fine for failing to fill in his log book, but was issued a summons to appear in court next month for getting back on the road just eight and a half hours after knocking off.
He intends pleading guilty, to face a minimum month-long suspension of his heavy vehicle licences, and another fine, of up to $3000.
"Yesterday was my latest finish for a long time - I just did one extra load, and wish I hadn't," he told the Herald.
"I didn't even think - I didn't do my logbook - if I had done, I would have realised I was starting too early."
The driver admitted, while waiting several hours for a relief driver to take his truck and its load of trees to its destination, of being aware of the dangers of fatigue.
He denied being under deadline pressure, saying he just enjoyed being back on the road after 11 months on home detention, and dreaded the prospect of being grounded again.
"I love it - I have only been back at work for three weeks," he said.
"It was my choice. What I don't like is everyone blaming the bosses. It's the driver who is responsible - if you can't say no, that's your fault."
Alex Currie, national technical advisor to the 117-strong police commercial vehicle inspection force including his own 25-member squad of A-grade mechanics, says patience and alertness are critical for truckies.
"You've got to have a cool head. It's a demanding job to negotiate 44,000 kilos on the road, with everything else going on."
But he supports "wholeheartedly" the Transport Agency issuing high-productivity permits for heavier and longer loads than the normal maximum of 44 tonnes and 20m, saying it reduces overall truck movements and displaces older vehicles.
The heaviest truck inspected during the Herald's visit was full of flour, and had a permit allowing a gross weight of 53 tonnes.
Another to pass all checks, including by the country's only police-operated portable roller brake testing machine, was crammed with Christmas chocolate but weighed just 26 tonnes on a pair of portable scales as its trailer was empty.
Despite having his run from Hamilton to Auckland interrupted by 20 minutes or so, the driver praised the police.
"You're only doing your job. Fair enough, there are idiots out there," he told them. But he said truck drivers were often unfairly blamed for crashes.
"I've seen a couple of trucks run off the road by cars - since we're big, people think we're the cause of everything, but some of these car drivers need to improve their performance."
Even so, Mr Soepnel is alarmed truckies were found at fault in almost half the Waikato-Bay of Plenty crashes in which they were involved in the two and a half years to June.
"Forty six per cent for professional drivers is very, very poor," he said.
He is heartened by a lower figure of 33 per cent for the four months to April, compared with 37 per cent nationally and 60 per cent in the Waikato and Bay Plenty last year, but is not relaxing his guard.
"Hopefully 2014 was an anomaly, but we should not assume this."
Drivers stopped during the campaign were also given key-rings pleading with them to slow to 10km/h below recommended maximum speeds on bends.
Mr Soepnel said speed was the primary cause of three fatal and six serious-injury truck crashes on his turf in the two and a half years to June 30, all on bends and involving no other vehicles.
"Which means heavy vehicle drivers are killing themselves."
Insecure loads were another focus of his campaign, leading to a truck carrying flammable paint thinners having a thorough going-over after its curtains were opened to reveal many drums not strapped down.
"So they were free to float around - big drums of dangerous goods," said Senior Constable Peter Bartrum, a former coach-builder but newcomer to commercial vehicle investigations, having transferred his diplomacy skills from youth aid work.
"If he's driving along then has to jam on the brakes for whatever reason, the next thing we've got is flammable goods being strewn about."
Although he handed the driver a $600 fine, he said he could have been harder on him.
"There were probably a couple more I could have given him, but it's give and take," Mr Bartrum said.
"It was an opportunity to provide education. We're not here to hammer people - we're here to ensure they're safe on the roads, making them safe for everyone."
Mr Soepnel, who drives a truck for Te Awamutu's volunteer fire brigade in his spare time, said laziness rather than time pressure was usually behind failing to secure loads.
"Unfortunately, when they close the [truck] curtains, they think out of sight, out of mind - but everything's got to be tied down."
He said most drivers and freight operators complied with the rules, but the Christmas month was when extra pressure piled on to deliver goods on time.
"Obviously you've got operators who will cut costs to undermine good operators to get the work - I guess we are like the referees, trying to keep a level playing field out there."
Operation Iron Curtain
Participants: 28 police and vehicle safety officers at five checkpoints across the northern Waikato, supported by highway patrols.
• More than 52 per cent of the national truck fleet passes through the Waikato, much of it servicing the country's big three ports of Auckland, Tauranga and Taranaki. • Truck drivers were to blame for 46 per cent of crashes involving their rigs in the Waikato and Bay of Plenty in the 30 months to June 30. • Freight firms are under extra pressure to deliver goods for Christmas. Main police focus of the campaign: • Fatigue • Inattention ?Speed ?Insecure loads