But first... ask yourself why, when everyone around you suddenly looks up at the sky do you do the same? When you go abroad to a place you've never been before do you end up settling on the restaurant with people sitting outside, the one everyone else has chosen?

If this sounds familiar, then you have experienced something called Social Proof. Put simply, 'the wisdom of the crowd'. Social Proof centres on the idea that people's behaviour is largely shaped by the behaviour of others around them, especially people they perceive to be trustworthy and credible. In moments of uncertainty people look to what other people are doing as a short-cut to making a good decision.

Taking this back to 20mph, if people perceive that their neighbours are positive about the introduction of 20mph on their street, tit is far more likely that they will also adopt a positive stance. If they see other drivers in the vicinity adhering to the new speed limits they are more likely to follow suite and do the same.

Four things we want to share

At So-mo we use our knowledge of behavioural insight to design behaviour change campaigns. Here are our four top tips to delivering a successful campaign based on what has worked in Liverpool.

  1. Consider who delivers the message. The public are far more responsive to messages from people they perceive to be similar to them. Conversely, they are far less responsive to traditional public sector messaging.
  2. Make public support as visible as possible. If you read press articles or see our social media coverage of 20mph in Liverpool it is unlikely you will see stories, films and images of our local politicians or council leaders. Instead you will see Liverpool people, out there doing a whole range of activities in support of 20mph. Part of our job is to find, co-design and then scale local activity, ensuring these community-based stories get good coverage in the media.
  3. Use teachable moments. Sometimes when people engage with our campaign they have a really powerful response to what they experience. At this moment they are really open to receiving messages. This often happens when we deliver "kids court", a joint initiative with Merseyside Police. We make use of these opportunities to help people adopt risk-reducing behaviours. Watch "Kids Court" on The One Show here.
  4. Help people feel good not bad about themselves. At the end of the day we want to people see themselves in a positive light. So, even when we stop speeding drivers as we do when we deliver roadside education, we want them to see themselves as having been through an experience, which has changed them for the better. We then encourage them to share this with others, creating a ripple effect.

Our goal?

Desirable behaviour that is self-enforced, based on a shared understanding of what is socially acceptable.

Is it working?

Liverpool's population is 467,000. So far 280,200 people have had their formal chance to object to proposed installation of signage. In just under three years only one person has ever raised an objection – saving the local authority thousands of pounds in officer time. This is different picture to what is happening in most other areas where, sometime tens and even hundreds of objections have been raised.

In terms of speed reduction – Liverpool are not releasing data until over 50% of the road network has been signed. This a campaign based on changing social norms and for that to really work you need the whole of the city's residential streets to be 20.

We know we are not quite there yet, but I think we are on the right road.

Nicola Wass

CEO and founder, So-mo