Contribution of traffic reduction to achieving zero-carbon

Why is this important?

Several national and international studies have shown that, in order to meet climate targets, it will not be sufficient just to electrify the vehicle fleet – this will be too slow a process and cannot resolve other issues such as particulate emissions from vehicle brakes, or traffic congestion. It will also be necessary to reduce traffic levels, particularly levels of car traffic. This might be expressed in terms of a reduction in mileage/kilometrage, or as a reduction in car trip modal share. This article gives examples of relevant policies and measures at the national and city level.

Within urban areas, reducing road traffic also contributes to achieving many other policy goals, including improved air quality and public health, and reduced traffic accidents and congestion; and provides the opportunity to rebalance streetspace, in favour of sustainable modes and place-making activities. The examples given below come from the UK.

Traffic reduction targets

Some national and city authorities have set out roadmaps to achieve a given reduction in car kilometres by a fixed date. For example, Transport Scotland has set out to achieve an average 20% reduction in national car kilometres by 2030, in addition to an extensive programme of electrification of the vehicle fleet and the provision of public charging points.

The report notes that:

“The route map does not aim to eliminate all car use. We recognise that would not be realistic or fair, especially for journeys undertaken by disabled people or in rural areas where sustainable travel options may not always be available or practical. Rather, the route map encourages all of us to reduce our overreliance on cars wherever possible and identifies four key behaviours that we want everyone in Scotland to consider each time we plan a journey:

1. make use of sustainable online options to reduce your need to travel;
2. choose local destinations to reduce the distance you travel;
3. switch to walking, wheeling, cycling or public transport where possible;
4. and combine a trip or share a journey to reduce the number of individual car trips you make, if the car remains the only feasible option.”

The roadmap that Transport Scotland has developed to achieve this 20% reduction, includes detailed milestones such as limiting speed to 20 miles per hour in built-up areas by 2025.

In line with this strategy, the City of Glasgow has set out its ambition to reduce car kilometres by 30% by 2030. Both documents emphasise the need for ‘Avoid’ as well as ‘Shift’ strategies, to achieve the needed reduction in car use.

Other UK cities have planned for reductions in car use through their modal share targets. In Greater London, for example, the Mayor’s Transport Strategy aims for an overall 80% modal share using sustainable modes (on foot, by cycle or using public transport) by 2041, with different targets for Central, Inner and Outer London. In 2015, the sustainable travel modal share was only 63%, so the website notes that: “This is a big task and achieving it won’t be easy”. It is supported by a series of Action Plans, covering, Buses, Cycling, Walking and Freight and Servicing, as well as Vision Zero for road collisions.

While highly ambitious given current conditions, this modal split target lags behind the most progressive cities in Europe. Vienna, for example, aims for an 80% sustainable modal share by 2025.