To Consider In Scheme Preparation This chapter, and Chapters 5 to 8 aim to outline good practice in the preparation of a new lighting scheme. In most instances the scheme preparation process will be led by the developer, but, all these parties have important roles to play. The process begins with an assessment of the need for lighting. The reasons for preparing a lighting scheme should be clear at the outset, and automatic assumptions should not be made that lighting is necessary. Lighting may not in fact be essential to the safety, security or viability of the development, and there should always be flexibility in the application of lighting standards.
Lighting has environmental, capital and maintenance costs.
These costs need to be weighed against the benefits of lighting. Such measures may obviate the need for lighting. At present there is no formal procedure for assessing the need for most forms of lighting. The exception is for roads, where the DoT and also many highway authorities conduct a cost-benefit analysis comparing the costs of installing and operating a lighting scheme over a 30 year evaluation period against the potential for accident reductions, which are quantified by using average road accident costs. 4.2 Initial Scheme Appraisal Having established that lighting is needed, an initial assessment of the specific lighting requirements of the task in hand should be made, and an outline scheme design prepared.