Abstract: A method of generating map data indicating a deviation from expected jam conditions on a segment of a plurality of segments in an area covered by an electronic map, the segment having associated therewith a jam probability indicating the likelihood of a jam on that segment. The method comprises establishing an expected jam condition for the segment based on the jam probability of that segment, and then obtaining live data indicating the jam conditions on at least one of the plurality of other segments in the area. A revised jam condition can then be established for the segment using the obtained live data.

Abstract: A method of generating map data indicating a deviation from expected jam conditions on a segment of a plurality of segments in an area covered by an electronic map, the segment having associated therewith a jam probability indicating the likelihood of a jam on that segment. The method comprises establishing an expected jam condition for the segment based on the jam probability of that segment, and then obtaining live data indicating the jam conditions on at least one of the plurality of other segments in the area. A revised jam condition can then be established for the segment using the obtained live data.

Abstract: A method of determining whether one or more navigable elements of a navigable network within a geographic area are still affected by a precipitation weather event. A quantity parameter is associated with each segment of an electronic map representing the navigable network and indicates the amount of precipitation remaining on the navigable element or portion thereof represented by the segment. The value of the quantity parameter increases in the presence of any precipitation weather event, and decreases ac cording to a predefined function with respect to time in the absence of any such precipitation weather event. A speed of travel of one or more devices along the navigable element or portion thereof represented by a segment is determined and compared to an expected speed of travel for the segment; the value of the quantity parameter being decreased based on the comparison.

Abstract: A method of determining whether one or more navigable elements of a navigable network within a geographic area are still affected by a precipitation weather event. A quantity parameter is associated with each segment of an electronic map representing the navigable network and indicates the amount of precipitation remaining on the navigable element or portion thereof represented by the segment. The value of the quantity parameter increases in the presence of any precipitation weather event, and decreases according to a predefined function with respect to time in the absence of any such precipitation weather event. A speed of travel of one or more devices along the navigable element or portion thereof represented by a segment is determined and compared to an expected speed of travel for the segment; the value of the quantity parameter being decreased based on the comparison.

Abstract: A method of determining whether one or more navigable elements of a navigable network within a geographic area are still affected by a precipitation weather event. A quantity parameter is associated with each segment of an electronic map representing the navigable network and indicates the amount of precipitation remaining on the navigable element or portion thereof represented by the segment. The value of the quantity parameter increases in the presence of any precipitation weather event, and decreases according to a predefined function with respect to time in the absence of any such precipitation weather event. A speed of travel of one or more devices along the navigable element or portion thereof represented by a segment is determined and compared to an expected speed of travel for the segment; the value of the quantity parameter being decreased based on the comparison.

Abstract: Live vehicle probe data is obtained relating to the movement of vehicles with respect to time along a navigable element. The probe data is used to determine a current speed of travel along the navigable element, which is compared to the free flow speed of travel for the navigable element. When the current speed of travel along the element is reduced relative to the free flow speed for the navigable element by less than a threshold associated with identifying a congestion event, and obtained weather data indicates the navigable element is affected by one or more adverse weather conditions, then a weather event is generated. If the reduction in speed of travel is of a size sufficient to trigger the generation of a congestion event, and obtained weather data again indicates the navigable element is affected by one or more adverse weather conditions, then one or more attributes of the congestion event can be used to determine if the cause of the congestion can be attributed to the adverse weather.

Abstract: A method of determining whether one or more navigable elements of a navigable network within a geographic area are still affected by a precipitation weather event. A quantity parameter is associated with each segment of an electronic map representing the navigable network and indicates the amount of precipitation remaining on the navigable element or portion thereof represented by the segment. The value of the quantity parameter increases in the presence of any precipitation weather event, and decreases according to a predefined function with respect to time in the absence of any such precipitation weather event. A speed of travel of one or more devices along the navigable element or portion thereof represented by a segment is determined and compared to an expected speed of travel for the segment; the value of the quantity parameter being decreased based on the comparison.

Abstract: A method of generating flow data indicative of speeds of travel within a navigable network in an area covered by an electronic map is disclosed. The electronic map comprises a plurality of segments representing navigable elements of the navigable network. Live vehicle probe data is obtained indicative of the average speed of travel for the current time with respect to distance along a link, the link being predetermined by reference to the electronic map. The link is sectioned to provide a plurality of sections along the length thereof. The sectioning is carried out based on the data indicative of the current average speed of time along the link. Where a differential in the current average speed exceeds a threshold, a new section is created.

Abstract: A method of identifying navigable stretches that are partially closed, e.g. due to the presence of roadworks, in a navigable network within a geographic area. A server obtains positional data relating to the movement of a plurality of devices along a navigable stretch with respect to time in a given time period, wherein the time period is a period of non-congested traffic flow. The positional data is used to determine an average speed of travel along the navigable stretch in the given time period. The determined average speed of travel is compared to a free flow speed for the stretch, and the navigable stretch is identified as being partially closed when the determined average speed of travel is lower than the free flow speed by a predetermined value.

Abstract: A method is provided of providing jam warning messages in relation to jams affecting navigable segments of a network of navigable segments. The method comprises, for each of one or more identified jams, obtaining a jam tail flow speed for the jam. The jam tail flow speed is preferably determined from the analysis of positional data relating to the current or relatively recent movement of a plurality of devices associated with vehicles along at least some navigable segments of a navigable network with respect to time. The jam tail flow speed is used to generate, or to determine whether to generate, a jam warning message in respect of the jam.

Abstract: A method of detecting the closure of a road element is disclosed; the road element being one of a set of alternative incoming or outgoing elements at a node in a network of navigable elements. A server obtains positional data relating to the position of a plurality of devices with respect to time traversing the node. A count is determined of the number of devices in a consecutive sequence of device selecting a given one of the navigable elements from among the set of elements. The count is compared to a predetermined threshold to determine whether another one of the elements is closed. The threshold is based upon the relative probability of the element to which the count relates being taken from the set of road elements.

Abstract: Live vehicle probe data is obtained relating to the movement of vehicles with respect to time along a navigable element. The probe data is used to determine a current speed of travel along the navigable element, which is compared to the free flow speed of travel for the navigable element. When the current speed of travel along the element is reduced relative to the free flow speed for the navigable element by less than a threshold associated with identifying a congestion event, and obtained weather data indicates the navigable element is affected by one or more adverse weather conditions, then a weather event is generated. If the reduction in speed of travel is of a size sufficient to trigger the generation of a congestion event, and obtained weather data again indicates the navigable element is affected by one or more adverse weather conditions, then one or more attributes of the congestion event can be used to determine if the cause of the congestion can be attributed to the adverse weather.

Abstract: A method of generating flow data indicative of speeds of travel within a navigable network in an area covered by an electronic map is disclosed. The electronic map comprises a plurality of segments representing navigable elements of the navigable network. Live vehicle probe data is obtained indicative of the average speed of travel for the current time with respect to distance along a link, the link being predetermined by reference to the electronic map. The link is sectioned to provide a plurality of sections along the length thereof. The sectioning is carried out based on the data indicative of the current average speed of time along the link. Where a differential in the current average speed exceeds a threshold, a new section is created.

Abstract: A method of generating map data indicating a deviation from expected jam conditions on a segment of a plurality of segments in an area covered by an electronic map, the segment having associated therewith a jam probability indicating the likelihood of a jam on that segment. The method comprises establishing an expected jam condition for the segment based on the jam probability of that segment, and then obtaining live data indicating the jam conditions on at least one of the plurality of other segments in the area. A revised jam condition can then be established for the segment using the obtained live data.

Abstract: A method of processing data relating to an electronic map, the map comprising a plurality of segments representing navigable segments in the area covered by the map, the method comprising using a processing apparatus to generate segment data and comprising the steps of: collecting historic travel data for the segment; defining a jam condition for the segment, such that where the jam condition is satisfied the segment is classified as jammed and otherwise as not jammed; generating a jam probability for the segment according to the historic travel data and the jam condition definition; generating a jam speed for the segment using the historic travel data, the jam speed being indicative of the speed on the segment when the segment is considered jammed; and associating the jam probability and the jam speed with the segment in the electronic map.

Abstract: A method of generating expected average speeds of travel across one or more segments in the area covered by an electronic map, each segment representing a navigable segment in the area covered by the map and having associated therewith: an average speed of travel across that segment; segment data comprising at least one jam probability, the jam probability indicating the likelihood of a jam on that segment; and a jam speed indicative of the speed of travel on that segment when it is considered jammed. The method comprises using the segment data to predict whether a jam condition exists on at least one or each of the segments; and outputting the expected average speed of travel across these segments as: a) a first speed, where a jam condition is predicted to exist, the first speed being the jam speed for the relevant segment or a speed based thereon, or b) a second speed, where a jam condition is not predicted, the second speed being the average speed for the relevant segment or a speed based thereon.

Abstract: A method is provided of providing jam warning messages in relation to jams affecting navigable segments of a network of navigable segments. The method comprises, for each of one or more identified jams, obtaining a jam tail flow speed for the jam. The jam tail flow speed is preferably determined from the analysis of positional data relating to the current or relatively recent movement of a plurality of devices associated with vehicles along at least some navigable segments of a navigable network with respect to time. The jam tail flow speed is used to generate, or to determine whether to generate, a jam warning message in respect of the jam.

Abstract: A method of identifying navigable stretches that are partially closed, e.g. due to the presence of roadworks,in a navigable network within a geographic area. A server obtains positional data relating to the movement of a plurality of devices along a navigable stretch with respect to time in a given time period, wherein the time period is a period of non-congested traffic flow. The positional data is used to determine an average speed of travel along the navigable stretch in the given time period. The determined average speed of travel is compared to a free flow speed for the stretch, and the navigable stretch is identified as being partially closed when the determined average speed of travel is lower than the free flow speed by a predetermined value.

Abstract: A method and system for identifying a lateral deviation in the course of a road segment is described. Positional data is collected from a plurality of vehicles travelling along a road stretch. A map matching error associated with the position data is used to determine an average map matching error and average absolute map matching error for travel along the road stretch. A lateral deviation in course is identified when the average map matching error measures are both above a given threshold, and where the detected deviation is of a given minimum length. Other indicators of deviation can be considered including a direction of the possible deviation, and impact on travel in the opposite driving direction. Data relating to the determined deviation is generated, including a speed of travel through the deviated region, and used to enhance traffic information.

Abstract: A method of detecting the closure of a road element is disclosed; the road element being one of a set of alternative incoming or outgoing elements at a node in a network of navigable elements. A server obtains positional data relating to the position of a plurality of devices with respect to time traversing the node. A count is determined of the number of devices in a consecutive sequence of device selecting a given one of the navigable elements from among the set of elements. The count is compared to a predetermined threshold to determine whether another one of the elements is closed. The threshold is based upon the relative probability of the element to which the count relates being taken from the set of road elements.