Human nature is a perverse thing. It consistently thwarts all attempts to coerce us into behaving the way bureaucrats, politicians and assorted control freaks think we should.

Take the road toll. Since early December New Zealanders have been subjected to a ceaseless barrage of police propaganda about the futility of trying to defy speed and alcohol limits.

Stern-looking police officers have been in our faces almost daily, warning that zero tolerance would be shown to lawbreakers. I'm sure I'm not the only one who has found their lecturing increasingly tiresome and patronising.

Of course the police can claim the best possible justification for all this finger-wagging: it's about saving lives. But what was the result? The road toll for the holiday period was more than double those of the previous two years. For the full year, the toll was up by 44 on the record low of 2013.

The figures suggest that people crash for all manner of reasons, and that the emphasis on speed and alcohol is therefore simplistic. The police focus on speed and booze because these are easy targets, and when the road toll comes down they can take the credit.

In the ideal world envisaged by ever-hopeful bureaucrats, wayward citizens can be managed much as sheep are controlled by heading dogs. But people will never be harangued into driving safely; human nature is just too contrary.

Besides, police crackdowns are only one factor in achieving a lower road toll.

Improved road design, safer cars, better-equipped emergency services and more immediate medical attention all contribute too. It would be interesting to know, for example, how many lives have been saved because of the use of helicopters to get victims promptly to hospital.

Given that their heavy-handed propaganda campaign appears to have had minimal effect, I wonder if the police will now be humble enough to sit down and review their tactics.

They might also ponder the potential damage done to their public image by the zeal with which they immediately began enforcing the new alcohol limits.

It must have been like shooting fish in a barrel as they set up checkpoints to catch otherwise law-abiding citizens who had inadvertently consumed one glass of sauvignon blanc too many.

It was a formidable display of police power, but how many lives did it save? And how many of the apprehended drivers were left feeling humiliated and angry at being made to feel like criminals for unwittingly doing something that was legal only days before, and that probably posed no danger to anyone?

Police will say, of course, that they were merely enforcing the law. But there is a point at which the benefits of aggressive law enforcement have to be weighed against potential negative consequences, such as public resentment. I'm not sure our police bosses have done this equation.

Sir Robert Peel, the 19th century British politician who established the police force on which ours is modelled, established the principle that police must operate with the consent of the people they serve. Put another way, they can't risk burning off public goodwill.

Judging by public reaction to the zero tolerance campaign, as expressed in forums such as letters to the editor, talkback shows and online news sites, that's exactly what is now happening.

This is the consequence some police officers feared when the old enforcement branch of the Ministry of Transport merged with the police in 1992. They realised the negative public sentiment attached to traffic cops was likely to rub off on police. And so it has turned out.

We tend to associate the phrase "police state" with brutal fascist regimes, but the term can apply to any country where the law is enforced so zealously that it impinges on the lives of responsible citizens. It's not overstating things to suggest that our own police are in danger of slipping into that danger zone.

In November, TV3 reported that police had thrown an impregnable cordon around Hamilton's CBD on a Saturday night. No vehicle could get out (or in, presumably) without going through a checkpoint. To me, that sounds almost like a police state.

Yes, I know the object of the exercise was to catch lawbreakers, but I bet I wasn't alone in thinking we had crossed a new threshold. And I bet I wasn't alone in feeling uncomfortable at the obvious satisfaction of the police inspector in charge, who seemed to relish exerting such control over the lives of her fellow citizens.

* Comments on this article are now closed.