Trees could become a green weapon against speeding motorists following the success of an innovative planting scheme that challenges drivers' perceptions.Provisional results from a road safety initiative in four Norfolk villages show strategic positioning of trees led drivers to reduce their speed by an average of two miles per hour.

Norfolk County Council planted 200 trees in four villages – Martham, Horstead, Mundesley and Overstrand – in an effort to reduce average speeds by two to three miles per hour and cut accidents by 20 per cent. There had been 20 crashes in the rural spots over a five-year period.

The initiative was about changing the environment to alter motorists’ perspectives. The planting of trees and hedges is designed to reduce speed “by playing with the driver’s peripheral vision”. One technique involved placing trees – at decreasing distances apart – on the approach to a village, tricking drivers into thinking they were speeding. “If you are staying at a constant speed, your peripheral vision (which takes in the trees) is giving you the impression you are going faster”.

Another method was to plant trees “so that is looks like the environment is closing in on the driver”, he added. The road remains the same width but trees are planted on a “lazy diagonal” that gets narrower towards the entrance to the village.

Given these favourable results, Norfolk County Council are now seeking to work with other parishes to undertake similar schemes. Alternative funding has been sought and the Council now has several more schemes underway.The overview of the project pointed out that ‘the condition of the surviving banks depends on subsequent land use. Plantations of forestry have generally served to preserve banks, although these are sometimes damaged by harvesting machinery. However, the warrens which became arable land have often lost their banks to the plough and other agricultural activity’ (page 38)