Real-time speed profile calculation for fuel saving considering unforeseen situations and travel time

Driving style is a key variable which we can influence in order to reduce consumption and pollutant emissions, but other variables also need to be taken into account, such as safety, comfort and travel time. There are different alternatives for obtaining the optimal speed and gear by taking into account the vertical profile of the road and vehicle characteristics. Of these alternatives, Dynamic Programming (DP) provides fairly satisfactory results. However, this calculation involves a high computation cost when it is used to calculate long routes, which poses practical problems when the route can be varied frequently or when unexpected traffic events make it necessary to recalculate the speed profile. This study proposes a solution that is closer to the optimal solution. The algorithm is based on simple action rules for elementary road profiles that have been previously obtained using DP. Furthermore, these rules are recalculated in order to fulfil a predefined travel time. The algorithm has been used in different traffic situations on a real route and differences with the optimal solution have been evaluated so that the conditions where it works better are assessed.