A method comprising: receiving information corresponding at least to (i) a state of charge of an energy storage of a vehicle, (ii) route information corresponding to a planned driving route for the vehicle, and (iii) a predicted driver characteristic; determining using the received information, and presenting to a driver of the vehicle, a first energy-versus-distance measure for the planned driving route; receiving a user input indicating a proposed change in at least the predicted driver characteristic, and determining using the received information and the user input, and presenting to the driver, a second energy-versus-distance measure for the planned driving route that takes into account the proposed change; wherein: the first energy-versus-distance measure is based on historical information; characterized in that after the vehicle has been driven for part of the planned driving route, a third energy-versus-distance measure is determined based on the driven part of the planned driving route, the third energy-versus-distance measure modifying the first energy-versus-distance measure using a model error and a driver error, wherein the model error is an accumulated error in predicting energy consumption over the driven part of the planned driving route and wherein the driver error is an accumulated error resulting from a characteristic of the driver differing from the predicted driver characteristic over the driven part of the planned driving route; and in response to the user input, the second energy-versus-distance measure is determined by modifying the first energy-versus-distance measure using the proposed change and the model error, but not the driver error. receiving information corresponding at least to (i) a state of charge of an energy storage of a vehicle, (ii) route information corresponding to a planned driving route for the vehicle, and (iii) a predicted driver characteristic; determining using the received information, and presenting to a driver of the vehicle, a first energy-versus-distance measure for the planned driving route; receiving a user input indicating a proposed change in at least the predicted driver characteristic, and determining using the received information and the user input, and presenting to the driver, a second energy-versus-distance measure for the planned driving route that takes into account the proposed change; wherein: the first energy-versus-distance measure is based on historical information; characterized in that after the vehicle has been driven for part of the planned driving route, a third energy-versus-distance measure is determined based on the driven part of the planned driving route, the third energy-versus-distance measure modifying the first energy-versus-distance measure using a model error and a driver error, wherein the model error is an accumulated error in predicting energy consumption over the driven part of the planned driving route and wherein the driver error is an accumulated error resulting from a characteristic of the driver differing from the predicted driver characteristic over the driven part of the planned driving route; and in response to the user input, the second energy-versus-distance measure is determined by modifying the first energy-versus-distance measure using the proposed change and the model error, but not the driver error. the first energy-versus-distance measure is based on historical information; characterized in that after the vehicle has been driven for part of the planned driving route, a third energy-versus-distance measure is determined based on the driven part of the planned driving route, the third energy-versus-distance measure modifying the first energy-versus-distance measure using a model error and a driver error, wherein the model error is an accumulated error in predicting energy consumption over the driven part of the planned driving route and wherein the driver error is an accumulated error resulting from a characteristic of the driver differing from the predicted driver characteristic over the driven part of the planned driving route; and in response to the user input, the second energy-versus-distance measure is determined by modifying the first energy-versus-distance measure using the proposed change and the model error, but not the driver error.