1. THE POTHOLE PATROL Using a Mobile Sensor Network for Road Surface Monitoring http://nms.csail.mit.edu/papers/p2-mobisys-2008.pdf Timothy Werner

2. Problem Potholes are everywhere Hard to find Car damage Lawsuits against the state Insurance claims

3. Solution

4. Test Deployment Attached to seven taxis in Boston for 10 days Covered nearly 2500 distinct kilometers Nearly 10000km total

5. Test Deployment - Accelerometer Placement Attached to car’s dashboard (glove compartment) Accurate Unobtrusive

6. Test Deployment – Training Data Trained for type of anomaly Crosswalks and Expansion Joint Railroad Crossing Pothole Manhole Stopping Turning

7. Pothole Detection Algorithm Speed High-pass z-peak xz-ratio Speed vs z ratio

8. Pothole Detection Algorithm Blacklisting Speed bumps Bridges Etc False Negatives – absence of reports does not mean a smooth road Drivers naturally try to avoid pot holes Roads are wide

9. Evaluation Tested on three data sets Carefully labeled data Loosely labeled data The taxis driving around Boston

10. Evaluation - Goals Detect a low number of anomalies on smooth roads Missing potholes is okay

11. Evaluation Classification accuracy on hand-labeled data Performance improvement using loosely labeled training data Performance on loosely labeled roads Spot-checks on uncontrolled data

12. Evaluation - Performance