Jarrod Gilbert: Watch Christchurch to see how good building design can make cities safer

If Christchurch gets it right, the many "no-go" areas that we expect in central cities may be completely designed out. Photo / Geoff Sloan

While politicians in the US debate what to do around the plague of mass shootings occurring in their country, an unlikely group is taking definitive action: architects.

When a gunman killed 20 students at a school in Sandy Hook in Connecticut, the town decided to build a new school and the architects had crime in mind when they designed it.

The new school has a broad front entrance that allows for open surveillance while a rain garden - in effect, a form of moat - acts as a boundary. The entrances have been designed to allow greater control as to who enters the building.

The designing of buildings and public spaces to inhibit crime is not new. Crime Prevention Through Environmental Design, or CPTED (pronounced sep-ted), was devised in the 1970s but has become increasingly popular in recent times, including in New Zealand.

In fact, one of CPTED's leading exponents, Dr Franks Strokes, is a Kiwi.

Using his ideas as well as others from around the world, the Ministry of Justice devised CPTED principles in 2005 that they have pushed out to city councils around the country, although uptake has been variable. One place where CPTED has been adopted as a priority is in Christchurch. An inner city needing to be entirely rebuilt following earthquakes required careful thought and CPTED was seen as important to that.

Christchurch's top cop, Superintendent John Price, is an enthusiast of preventing crime rather than simply responding to it, and he is one who has identified the value of good design. "I'd rather not have to deploy [so many] police officers in the CBD, I want the CBD to largely police itself. And if we can do that through some basic CPTED principles, which we can, then we should".

One standout example in Christchurch is the Bus Interchange that replaced the pre-quake rabbit warren which was a hotbed of crime and disorder.

Statistics show that crime in the new interchange has dropped dramatically. Police calls for service are just a quarter in the new bus terminal compared to what they were in the old one. And while we must be extremely cautious making such comparisons because the city pre-quake and now is so different, even in relation to the temporary interchange crime has fallen sharply.

The police are convinced this has much to do with the new design, and if they're right then that's big.

What did these improvements cost? Well, in this instance, nothing. The architect told me that good CPTED does not have to increase the budget. He also said it should also be invisible to the public. This is because CPTED isn't an architectural style, it is a series of measures and techniques that can be applied to any kind of building or space. People may notice that a place "feels good" without knowing why.

The Bus Interchange in Christchurch includes toilet facilities that open directly on to a shared, observable foyer meaning people can be noticed if they are lingering in unusual ways. This discourages nefarious behaviour as the public unknowingly become guardians of the space. People are less likely to commit crime if they think they are being observed.

Alcoves and other potential entrapment spaces have been minimised, and the use of many visually permeable barriers in areas such as the bicycle storage area allow for observation ahead of travel, and maximise natural surveillance.

The footpath outside of the building is wide, and subtle changes in the pavement material mark the distinction between waiting and walking areas - to make it less likely people will bump into each other (particularly late-night revellers) and thus reduce the likelihood of fights.

But CPTED is not just about reducing crime. A key idea of CPTED is a rejection of a "fortress mentality" meaning it seeks to maximise the use of public spaces by connecting places together with corridors and pathways that are well lit and open. In doing so you don't just minimise crime, you increase liveability. When places feel safe people naturally use them more.

If Christchurch gets it right, the many "no-go" areas that we expect in central cities may be completely designed out.

While town planners and architects in New Zealand don't have to consider mass shootings like they do in the US, tackling complex issues like crime by designing spaces that are safe and inviting is nevertheless attractive here.

The Christchurch experience is one that we should all watch with interest.