The Pothole Patrol

1. The Pothole Patrol Using a Mobile Sensor Network forRoad 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 • Pothole Patrol () • Uses GPS and motion sensors • Deployable on existing vehicles • Taxis, garbage trucks, etc.

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