London Borough of Merton's behavioural insights project tested an intervention to reduce engine idling at a level crossing in Merton using a pre-post trial. The simple and often subconscious act of engine idling can have significant effects on air quality within the local area.
The simple and often subconscious act of engine idling can have significant effects on air quality within a local area.
Based on a literature review the council chose the message - ‘save money, save fuel, turn off your engine’ - using salience, self-interest and awareness raising.
Before the sign was in place, 37 percent of drivers turned their engine off. After the sign was in place, 50 per cent of drivers turned their engine off. This is a statistically significant increase of 13 percentage points.
The challenge
Air pollution is one of the biggest environmental threats to health in the UK. The simple and often subconscious act of engine idling can have significant effects on air quality within a local area.
The solution
A behaviourally-informed sign at a level crossing, encouraging drivers waiting to turn off their engine.
The impact
Based on conservative assumptions about the number of vehicles waiting at the level crossing each day, if the results hold in the future we estimate:
- Each day, 79 fewer vehicles will idle at the level crossing site.
- Each week - assuming that traffic is halved at the weekend - 474 fewer vehicles will idle at the level crossing site.
- Each month, 2,015 fewer vehicles will idle at the level crossing site.
- Each year, 24,648 fewer vehicles will idle at the level crossing site.
How is the new approach being sustained?
The sign remains in place and is performing the same function as it did during the trial.
Lessons learned
The project has shown that idling can be reduced through nudging. These results support the theory that habitual behaviour is preventing drivers from turning their engine off when stationary. This means that salient prompts to remind them can be effective. It was also found that targeting financial self-interest is effective, it is suspected this is especially the case in present times, with high fuel prices and the rising cost of living.
Contact
Miar Crutchley, Lead Officer Air Quality & Contaminated Land, The London Borough of Merton at [email protected]
Dr Craig Johnson, Behavioural Insights Team at [email protected]