New Zealand Speed signs provide safe travelling speed limit or guidance information to drivers on roads. The speed signposts are provided alongside the national roads and highways as a part of guidance system for drivers and are entrenched by the New Zealand Transport Agency (NZTA). The speed limit in New Zealand is decided by the speed limits policy of NZTA.

The objective of speed limits policy is to balance the interests of mobility and safety by ensuring speed limits are safe, appropriate and credible for the level of roadside development and the category of road for which they are set. In New Zealand, speed limits may be temporary, changing kilometre by kilometre or hour to hour. The research undertaken is to develop a commercially effective NZ Speed sign recognition system to be used at Geosmart NZ Ltd. Geosmart (NZ) Ltd is New Zealand's geospatial solutions provider. The current system being used to determine the speed signs is a manual system, where a human input is required to observe terabytes of data. To speed up the process and get accurate information, the company requires an automated system to detect changes in the speed limits in short interval of time at different areas on the country’s roads. This research will aim at finding an efficient solution for recognition of NZ based road signs in software, especially when the speed signs are located in dark or gloomy images. This research proposes a new method to treat images with low level lighting conditions during the process of colour segmentation, a method used in digital image processing.