Virtual RSA Sign System for Speed Limit Information Delivery
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Solution Overview
Problem
RSA signs are not uniformly placed in many regions, leading to unexpected speed limit changes for drivers, and existing computer vision technologies may misclassify speed limit signs, resulting in unsafe and uneconomical deceleration.
Innovation Solution
A virtual RSA sign system that determines the vehicle's position and speed limit changes, displaying a visual representation of the approaching segment's speed limit within a designated presentation zone, integrated with traffic sign recognition functionality, to provide timely and accurate information to drivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RSA signs are uniformly placed, then drivers can anticipate speed limit changes and maintain safe speeds, but implementation cost and complexity increase due to required infrastructure modifications
Solution Approach 1:
The patent creates a virtual copy of the RSA sign functionality through software-based traffic sign recognition systems. Instead of deploying physical signs with precise positioning, the system uses image processing to detect and interpret existing speed limit signs, then delivers the information to drivers through in-vehicle displays. This copying approach achieves reliable speed limit information delivery without the infrastructure complexity of uniform physical sign placement.
Solution Approach 2:
The patent replaces the mechanical/physical infrastructure system of uniformly placed RSA signs with an electronic information processing system. The solution uses computer vision algorithms, GPS positioning, and digital communication to deliver speed limit information, substituting the need for physical sign infrastructure while maintaining or improving reliability through flexible, software-based delivery mechanisms.
2Extent of automation
If computer vision technology is used to read speed limit signs, then automated speed limit detection is achieved, but misclassification of RSA signs as legal speed limit signs occurs
Solution Approach 1:
The patent segments the speed limit sign detection process into distinct phases: detection of the sign, extraction of speed limit information, classification of the sign type (RSA vs. legal speed limit), and delivery of appropriate information. By segmenting the automation process, the system can apply different processing rules and validation checks at each stage, improving classification accuracy while maintaining high automation levels.
Solution Approach 2:
The patent introduces an intermediary classification layer between sign detection and information delivery. This intermediary system analyzes contextual factors such as sign positioning, accompanying signage, and road geometry to distinguish RSA signs from legal speed limit signs. The intermediary prevents misclassification by adding a verification step that considers multiple data sources before determining the appropriate speed limit information to deliver.
3Reliability
If RSA signs are placed far ahead of reduced speed zones, then drivers have more time to react and adjust speed, but drivers may decelerate too early causing energy inefficiency
Solution Approach 1:
The patent implements dynamic adjustment of the information delivery timing based on real-time vehicle speed, distance to the speed limit sign, and road conditions. Rather than using a fixed placement distance, the system calculates the optimal delivery point dynamically, ensuring drivers receive information at the appropriate moment to react safely while minimizing unnecessary deceleration and energy consumption.
Solution Approach 2:
The patent delivers speed limit information in advance of the actual speed limit change point, but uses algorithms to optimize the timing and distance of delivery. The system performs preliminary calculation of the optimal notification distance based on vehicle speed and road conditions, providing just enough advance notice for safe driver reaction while avoiding overly early notification that would cause unnecessary energy consumption from premature deceleration.
Data Source
AI summary
A navigation system provides a position of the vehicle on a segment of a roadway and identifies a change in speed limit relative to the current segment of the roadway. A traffic sign recognition system determines a speed limit information presentation zone of the current segment of the roadway after determining that a speed limit of the approaching segment of the roadway is lower than a speed limit of the current segment of the roadway and/or a current speed of the vehicle. Thereafter, the traffic sign recognition system assesses the position of the vehicle relative to the speed limit information presentation zone. In response to determining that the vehicle is within the speed limit information presentation location, the traffic sign recognition system displays a visual representation of a speed limit sign designating the speed limit of the approaching segment of the roadway.