20mph reduces the power imbalance between road users so some drivers can choose to drive less far or less often.  It also smooths traffic flow. Independent travel by the young and vulnerable groups rises too.

Most UK towns are jammed. No one wins!  Behaviour change to cut traffic is now an aim of those managing roads in many places.  Our environment, road rules, taxes and individual circumstances all affect the choice of how to go.  20mph road speeds lead to smarter (less car use) choices. To nudge those with car access not to choose driving, we suggest making the alternatives more attractive.  20mph limits effectively does that – it’s safer, less polluted, quieter and feels friendlier.  The choice not to drive is more pleasant.   

Changing the road environment is a cost effective one-off method of enabling traffic reduction. 20mph limits reduce speed long term. It’s low hanging fruit - as it’s inexpensive, effective long term and popular.

Fear of road injury is the top concern for many when getting about.  Some politicians – eg the Mayor of London - have declared road death and injury will not be tolerated - Vision Zero.  20mph limits are key to reducing both the number and severity of road trauma since lower speeds are the best way to cut kinetic energy and give everyone more time and space to avoid collisions.  As speeds fall, people start to feel safer and more willing to walk, cycle and take public transport. Traffic volumes also fall. Traffic reduction of 3% was reported in Edinburgh’s trial of 20mph limits and more walking and cycling has been a reported result in many 20mph schemes.

When 20mph is the top limit, traffic flow smooths with drivers being able to join from junctions and filter more easily. Trip times don’t change significantly, the perceived time advantage of cars seems less which nudges the power imbalance away from driving. 20mph helps reduce pollution too as less acceleration means less fuel is burnt and there’s less brake and tyre wear. It can almost halve noise levels making the public realm more pleasant.

Whilst some effective motoring reduction policies like a fuel tax escalator, are policy decisions for national politicians, local Councillors have powers over local road speeds.

Citizens can help by calling on their elected local politicians for speed limit reduction. This gives a mandate to act. Most solutions are known. Responsible politicians will wish to deter solo motoring and promote the alternatives, plus commit to make roads safer for all, especially vulnerable road users.

The ideal is voluntary compliance from drivers receptive to messaging on the benefits of 20mph. New drivers in 20mph areas learn to drive at 20mph. Speed limiters exist on many cars and will be fitted on all new vehicles from 2022.  A culture of more considerate road behaviour and slower speeds as the norm thus develops over time. 

Police forces are beginning to align their targets with Local Authorities and Public Health to include active travel aspirations. There are ways for Local Authorities to take on enforcement duties and many want to because they realise that overcoming speeding is a critical factor in people choosing an alternative to driving.

As the public realm becomes a safer, nicer place to be, more will opt to go by foot, cycle or take public transport.  20mph is a key requirement for traffic reduction, less car use and less fuel use. It sets the foundation for better places for us all to move around without necessarily using a car.

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