A method for estimating a traffic volume in respect of a given time for a given segment of an electronic map representing a navigable network in an area, the electronic map comprising a plurality of segments representing navigable elements of the navigable network in the area, wherein the navigable network in the area includes navigable stretches which are associated with at least one traffic detector and navigable stretches which are not associated with any traffic detector, and wherein the given segment is a segment representing at least a portion of a navigable stretch of the navigable network in the area which is not associated with any traffic detector, wherein the electronic map further comprises a plurality of reference segments, each reference segment being a segment representing at least a portion of a navigable stretch of the navigable network in the area which is associated with a traffic detector, and wherein each reference segment is associated with data indicative of a respective reference scaling coefficient for the given time, the reference scaling coefficient being based on a measured count of vehicles traversing the at least a portion of the stretch represented by the reference segment in respect of the given time and a count of devices associated with vehicles traversing the at least a portion of the stretch represented by the reference segment in respect of the given time, the measured count of vehicles being based on data measured by the at least one traffic detector associated with the stretch, and the count of devices associated with vehicles being based on positional data and associated timing data relating to the movement of a plurality of devices having position determining capability along the at least a portion of the stretch represented by the reference segment, the method comprising: estimating the traffic volume for the given segment in respect of the given time using data indicative of a count of devices associated with vehicles traversing the at least a portion of the stretch of the navigable network represented by the given segment in respect of the given time and an estimated scaling coefficient for the given time for the given segment, wherein the estimated scaling coefficient for the segment is based on the reference scaling coefficients associated with each one of a subset of one or more reference segments of the electronic map which are associated with the given segment, and wherein the count of devices is based on positional data and associated timing data relating to the movement of a plurality of devices having position determining capability with respect to time along the at least a portion of the navigable stretch represented by the given segment; and generating data indicative of the estimated traffic volume for the given segment in respect of the given time; wherein the electronic map further comprises, for each segment that is not a reference segment, data indicative of the subset of one or more reference segments associated with the segment; and/or wherein the method further comprises: determining the subset of one or more of the reference segments which are associated with the given segment. estimating the traffic volume for the given segment in respect of the given time using data indicative of a count of devices associated with vehicles traversing the at least a portion of the stretch of the navigable network represented by the given segment in respect of the given time and an estimated scaling coefficient for the given time for the given segment, wherein the estimated scaling coefficient for the segment is based on the reference scaling coefficients associated with each one of a subset of one or more reference segments of the electronic map which are associated with the given segment, and wherein the count of devices is based on positional data and associated timing data relating to the movement of a plurality of devices having position determining capability with respect to time along the at least a portion of the navigable stretch represented by the given segment; and generating data indicative of the estimated traffic volume for the given segment in respect of the given time; wherein the electronic map further comprises, for each segment that is not a reference segment, data indicative of the subset of one or more reference segments associated with the segment; and/or wherein the method further comprises: determining the subset of one or more of the reference segments which are associated with the given segment.