# US 2018/0023973 A1 · Extrapolating speed limits within road graphs > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0023973 A1 - Document ID: US20180023973A1 - Status: Published application - Kind: A1 - Application number: 15/653,314 - Filed: 2017-07-18 - Published: 2018-01-25 - Earliest claimed: 2016-07-20 - Assignees: Harman Becker Automotive Systems GmbH - Applicants: Harman Becker Automotive Systems GmbH - Inventors: Volodymyr Ivanov; Alexey Pryakhin; Ievgenii Borshch - Web page: https://patentgrep.com/patent/US20180023973A1 ## CPC - G08G 1/0104: {Measuring and analyzing of parameters relative to traffic conditions} - G01C 15/002: {Active optical surveying means (optical plumbing G01C15/105)} - G01C 21/26: specially adapted for navigation in a road network - G01C 21/28: with correlation of data from several navigational instruments - G01C 21/30: Map- or contour-matching - G01C 21/3415: {Dynamic re-routing, e.g. recalculating the route when the user deviates from calculated route or after detecting real-time traffic data or accidents} - G01C 21/36: Input/output arrangements for on-board computers - G01C 21/3697: {Output of additional, non-guidance related information, e.g. low fuel level (G01C21/3679 takes precedence)} - G01C 21/3815: {Road data} - G01S 19/51: Relative positioning - G01S 19/53: Determining attitude - G06F 8/65: Updates (security arrangements therefor G06F21/57) - G06F 9/44526: {Plug-ins; Add-ons} - G06F 16/284: {Relational databases} - G06F 16/29: Geographical information databases - G06F 17/10: Complex mathematical operations {(function generation by table look-up G06F1/03; evaluation of elementary functions by calculation G06F7/544)} - G06T 7/12: Edge-based segmentation - G06T 17/05: Geographic models - G08G 1/0112: {from the vehicle, e.g. floating car data [FCD]} - G08G 1/052: with provision for determining speed or overspeed {(speed measuring in general G01P)} - G08G 1/093: {Data selection, e.g. prioritizing information, managing message queues, selecting the information to be output} - G08G 1/09623: {Systems involving the acquisition of information from passive traffic signs by means mounted on the vehicle (G08G1/0967 takes precedence)} - G08G 1/0967: Systems involving transmission of highway information, e.g. weather, speed limits (transmission of navigation instructions to the vehicle G08G1/0968) - G08G 1/096716: {where the received information does not generate an automatic action on the vehicle control} - G08G 1/20: {Monitoring the location of vehicles belonging to a group, e.g. fleet of vehicles, countable or determined number of vehicles} - G08G: TRAFFIC CONTROL SYSTEMS (guiding railway traffic, ensuring the safety of railway traffic B61L; arrangement of road signs or traffic signals E01F9/00; radar or analogous systems, sonar systems, lidar systems specially adapted for traffic control G01S13/91, G01S15/88, G01S17/88; {radar or analogous systems, sonar systems, lidar systems specially adapted for anti-collision purposes G01S13/93, G01S15/93, G01S17/93}) - G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S) - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract In one embodiment, a speed limit application associates speed limits with road segments based on a road graph. In operation, the speed limit application selects a source road segment that meets a target road segment at an intersection based on the road graph. The source road segment is associated with a speed limit. Subsequently, the speed limit application determines a confidence value associated with extrapolating the first speed limit to the target road segment based on the first road graph. The speed limit application then determines that the confidence value indicates that a confidence in the extrapolation satisfies a minimum confidence requirement. Consequently, the speed limit application generates an attribute that associates the first speed limit with the target road segment. Finally, the speed limit application causes a navigation-related operation to be performed based on the attribute. ## Claims ### Claim 1 A method for associating speed limits with road segments, the method comprising: identifying a first road segment included in a first road graph as a source of a second road segment, wherein the first road segment is associated with a first speed limit and meets the second road segment at a first intersection; extrapolating the first speed limit to the second road segment based on the first road graph; generating a first attribute that associates the first speed limit with the second road segment; and causing a first navigation-related operation to be performed based on the first attribute. ### Claim 2 (depends on 1) The method of claim 1, wherein identifying the first road segment comprises: determining that the first intersection joins the first road segment and a third road segment to the second road segment; and comparing the first road segment, the second road segment, and the third road segment based on at least one of a functional road class, an angle, a number of lanes, and a road name to determine that the first road segment is the source of the second road segment. ### Claim 3 (depends on 1) The method of claim 1, wherein identifying the first road segment comprises determining that the first road segment is the only road segment that arrives at the first intersection in a first traveling direction, and the second road segment exits the first intersection in the first traveling direction. ### Claim 4 (depends on 1) The method of claim 1, further comprising associating the first speed limit with the first road segment based on one or more observations of a speed limit sign. ### Claim 5 (depends on 1) The method of claim 1, further comprising, prior to generating the first attribute: determining a first confidence value associated with extrapolating the first speed limit to the second road segment based on the first road graph; and determining that the first confidence value satisfies a minimum confidence requirement. ### Claim 6 (depends on 5) The method of claim 5, wherein determining the first confidence value comprises: computing a first value based on one or more confidence values associated with the one or more observations; computing an extrapolation length between the first intersection and the speed limit sign associated with the first speed limit; and computing the first value based on the confidence factor and the extrapolation length. ### Claim 7 (depends on 1) The method of claim 1, wherein identifying the first road segment comprises: determining that a first road sign indicating a type of road or neighborhood lies along the second road segment based on one or more attributes included in the first road graph; identifying a traffic law based on the type of road or neighborhood and a location of the first intersection; and determining that the traffic law indicates that a preceding speed limit is in force for the second road segment. ### Claim 8 (depends on 1) The method of claim 1, wherein causing the first navigation-related operation to be performed comprises adding the first attribute to the first road graph to generate a second road graph, and transmitting the second road graph to a navigation application, wherein the navigation application performs the first navigation-related operation. ### Claim 9 (depends on 1) The method of claim 1, further comprising: identifying the second road segment included in a first road graph as a source of a third road segment, wherein the second road segment meets the third road segment at a second intersection; extrapolating the first speed limit to the third road segment based on the first road graph; generating a second attribute that associates the first speed limit with the third road segment; and causing a first navigation-related operation to be performed based on the second attribute. ### Claim 10 A non-transitory computer-readable storage medium including instructions that, when executed by a processor, cause the processor to associate speed limits with road segments by performing the steps of: identifying a first road segment included in a first road graph as a source of a second road segment, wherein the first road segment is associated with a first speed limit and meets the second road segment at a first intersection; determining that the first speed limit is applicable to the second road segment; generating a first attribute that associates the first speed limit with the second road segment; and causing a first navigation-related operation to be performed based on the first attribute. ### Claim 11 (depends on 10) The computer-readable storage medium of claim 10, wherein identifying the first road segment comprises: determining that the first road segment splits into the second road segment and a third road segment at the first intersection; and comparing the first road segment, the second road segment, and the third road segment based on at least one of a functional road class, an angle, a number of lanes, and a road name to determine that the first road segment is the source of the second road segment. ### Claim 12 (depends on 10) The computer-readable storage medium of claim 10, wherein identifying the first road segment comprises determining that the first road segment is the only road segment that arrives at the first intersection in a first traveling direction, and the second road segment exits the first intersection in the first traveling direction. ### Claim 13 (depends on 10) The computer-readable storage medium of claim 10, further comprising associating the first speed limit with the first road segment based on one or more observations of a speed limit sign. ### Claim 14 (depends on 10) The computer-readable storage medium of claim 10, wherein determining that the first speed limit is applicable to the second road segment comprises: determining a first confidence value associated with extrapolating the first speed limit to the second road segment based on the first road graph; and determining that the first confidence value satisfies a minimum confidence requirement. ### Claim 15 (depends on 14) The computer-readable storage medium of claim 14, wherein determining the first confidence value comprises: computing an extrapolation length between the first intersection and a speed limit sign associated with the first speed limit; evaluating one or more intersections that lie between the speed limit sign and the second road segment to determine a complexity value, wherein the one or more intersections includes the first intersection; computing the first confidence value based on the extrapolation length and the complexity value. ### Claim 16 (depends on 10) The computer-readable storage medium of claim 10, wherein determining that the first speed limit is applicable to the second road segment comprises: determining that a first road sign indicating a type of road or neighborhood lies along the second road segment based on one or more attributes included in the first road graph; identifying a traffic law based on the type of road or neighborhood and a location of the first intersection; and determining that the traffic law indicates that a preceding speed limit is in force for the second road segment. ### Claim 17 (depends on 10) The computer-readable storage medium of claim 10, wherein causing the first navigation-related operation to be performed comprises adding the first attribute to the first road graph to generate a second road graph, and transmitting the second road graph to a navigation application, wherein the navigation application performs the first navigation-related operation. ### Claim 18 (depends on 10) The computer-readable storage medium of claim 10, further comprising: identifying the second road segment included in a first road graph as a source of a third road segment, wherein the second road segment meets the third road segment at a second intersection; determining that a first road sign indicating a type of road or neighborhood lies along the third road segment based on one or more attributes included in the first road graph; identifying a traffic law based on the type of road or neighborhood and a location of the second intersection; and determining that the traffic law indicates that a preceding speed limit is not in force for the third road segment and, in response, terminating an extrapolation of the first speed limit at the second intersection. ### Claim 19 A system for associating speed limits with road segments, the system comprising: a memory storing a speed limit application; and a processor coupled to the memory, wherein when executed by the processor, the speed limit application causes the processor to: identify a first road segment included in a first road graph as a source of a second road segment, wherein the first road segment is associated with a first speed limit and meets the second road segment at a first intersection; extrapolate the first speed limit to the second road segment based on the first road graph; generate a first attribute that associates the first speed limit with the second road segment; and cause a first navigation-related operation to be performed based on the first attribute. ### Claim 20 (depends on 19) The system of claim 19, further comprising associating the first speed limit with the first road segment based on one or more observations of a speed limit sign.