The Traffic Officer Service is a 24 hour- 365 day operation covering all the motorways in England and certain key interlinking trunk roads. Given the nature of the service it is essential that the vehicles which are provided for patrol activities are able to safely operate in adverse weather conditions such as snow and slippery surfaces, hence four wheel drive is considered to be essential. This drive provision also enables the vehicles to be used for certain carriageway clearance operations. There is also a further requirement for a high payload in order to carry the crew, essential kit and, where appropriate, passengers, which means that only vehicles of a particular size can safely be used.