Current warrants for climbing lanes are discussed, and the consequences of their usage are explored. Data were obtained and analysed to derive relationships among flow, gradient, and speed on South African roads. These relationships were used to calibrate TRARR, a simulation program developed by the Australian Road Research Board, and this, in turn, was used to establish relationships between delay and flow for various gradients. Actual delay is offered as an alternative warrant, it being pointed out that the highway capacity manual offers delay as a criterion of level of service. The paper postulates that delay suffered would not be a function of the gradient on which it occurs if the climbing lane were the subject of economic analysis. Various isochronistic warrants are offered for consideration with the consequences of adoption of this approach being pointed out.
Abstract