From 2023-2025, the County worked with third-party contractors to conduct a Tool-Based Before/After Studies project. The objective of the project was to evaluate how five engineering tools affected safety when applied in different location types in the County.
The tools assessed and topline findings in the study include:
- Curb modifications: Resulted in minor decreases in right turn vehicle speeds; More effective when markings accompanied by flex posts; More effective when bike lane not present.
- Hardened centerlines: Resulted in significant decreases in left turn speeds and percentage of vehicles crossing the yellow line while turning; More effective when both mini speed humps and flex posts are installed for hardening.
- Tactical speed humps: Resulted in significant decreases in speeds and speeding in school zone corridors; More effective when placed away from STOP sign locations.
- Speed limit pavement markings in school slow zones: Resulted in minor decreases in average 85th percentile speeds but helpful in reducing vehicles traveling above 30mph.
- No-turn-on-red signage: Resulted in moderate reduction in vehicles turning right on red; Some locations showed an increase in the amount of pedestrian/vehicle conflicts on the vehicular green/concurrent walk signal phases.
View the Before & After Studies Summary Report & Appendix here.(PDF, 8MB)