The Phase I study (retrospective) was completed for:
- Increased retroreflectivity of STOP signs.
- Flashing beacons at STOP-controlled intersections.
- STOP AHEAD pavement markings.
- Installing center two-way left-turn lanes on two-lane roads.
The Phase II study (retrospective) was completed for:
- Improved curve delineation.
- Offset improvements for left-turn lanes.
- Lane and shoulder width combinations on rural, two-lane, undivided roads.
- Advance street name signs.
The Phase III (build to evaluate) “before” evaluation is complete, and is currently in a data-collection period for “after” evaluation of:
- Surface friction treatment on curves.
- Surface friction treatment on ramps.
- In-lane pavement markings for curve warning.
- Larger chevrons.
- Edgeline rumble strips on curves.
- Red light indicator lights.
The Phase IV study is complete. This phase was conducted for:
- Rural two-lane undivided roads: nighttime delineation for curves (three strategies).
- Rural traffic calming for small towns (three strategies).
Phase V is a prospective study and the “before” evaluation is complete. This study is currently in a data-collection period for “after” evaluation of:
- Combination of centerline and edgeline rumble strips.
- Combination of median barrier and rumble strips.
- Signalized intersection multicountermeasures.
- STOP-controlled intersection multicountermeasures.
The Phase VI study, Pavement Safety Performance, is complete. Eleven strategies were evaluated for:
- Asphalt Pavement
- Thin hot-mix asphalt overlay.
- Chip seal, microsurfacing.
- Ultra-thin bonded wearing course.
- Open-graded friction course.
- Slurry seal.
- Concrete Pavement
- Diamond grinding.
- Ultra-thin bonded wearing course.
- Microsurfacing and grooving.
- High-Friction Surface Treatment (HFST).
Phase VII is a retrospective study. This study started in November 2012 and three of its four strategies are complete. The four strategies of this phase are:
- Pedestrian Countdown Signals (PCS).
- Continuous Green T-Intersection.
- Active Intersection Warning Systems/Dynamic Signing.
- Wet-Reflective Pavement Markings.
Phase VIII is a retrospective study. This study started in August 2013 and it is to be completed in:
- Signalized Restricted Crossing U-turn (RCUT).
- Flashing yellow arrows.
- Access management.
- Realignment of horizontal curvature.
- Profiled thermoplastic pavement markings.
Phase IX is a retrospective study that started in December of 2015. The study’s intent is to provide reliable crash modifications factors (CMFs) and benefit to cost (B/C) ratios for different types of HFST and to recommend materials, specifications, applications, and where and under what conditions to use them to effectively reduce roadway departure crashes. This study will quantify the performance of HFST over time to recommend HFST for best performances with technical details. Researchers will recommend a set of required tests with equipment for evaluating HFST surface characteristics and performance evaluation for practitioner use.
Phase X study started in June of 2017 for the Safety Evaluation of:
- Adaptive Signal Control Technologies.
- Bicycle lanes, added by reducing lane and/or shoulder width.
- Variable speed limits (VSL).
- Treatments to minimize the influence of light poles.
- Treatments to minimize the influence of guardrails.
- Side slope improvements.
- Bike lane configurations at intersections.
Phase XI study (start in early 2019) will include:
- Safety evaluation of miniroundabouts.
- Safety evaluation of wrong way driving (WWD) low cost safety improvements.
- A one-day workshop for effective WWD countermeasures.