Posted to the Flockton Bypass facebook group (10 April 2019) by David Rawling:
An extract from Section 12 of the link. The last paragraph tells us what the community already know, but needs the authorities to act upon:
The study has shown that the speed at which people drive is influenced more by the look and feel of the road, than whether a 20 mph or 30 mph limit is in place. It appears that some roads where 20 mph limits have been implemented are naturally ‘self-explaining roads’ where drivers ‘instinctively’ drive more slowly (because their length provides less opportunity to build-up speed, visibility may be limited, drivers do not feel that they have sufficient space to drive faster or feel that it is appropriate to do so, and because they serve local start/end destinations only). In other cases, the look and feel of the road naturally encourages higher speeds. In many cases the implementation of a 20 mph limit has simply formalised existing behaviour.
The challenge is how to change driver attitudes and behaviour in other locations. Evidence from this study (and others) shows that bigger speed reductions occur on faster roads, with higher volumes of traffic and providing a locally important strategic function.
Circular 01/2013 encourages authorities to consider introducing 20 mph limits on more major streets where foot and cycle movements are important, but also advises that where average speeds exceed 24 mph, the introduction of signage only is unlikely to lead to 20 mph compliance. This study supports this advice and confirms that on faster roads more needs to be done to achieve compliance and maximise the benefits. Even on these types of roads the actual reduction in speeds has been small, with lowering the speed limit using signs alone leading to a reduction in speed of about 1 mph. Without supporting measures to encourage compliance, there is a risk that non-compliance with the speed limit becomes the norm.
Road Safety Fact Sheet (20 mph zones)
20 mph speed limits on roads: Report into the effectiveness of 20 miles per hour (mph) road speed limits.