LOW COST SAFETY IMPROVEMENTS

1. LOW COST SAFETY IMPROVEMENTS Practitioner Workshop Exercise C– Session #9

2. Traffic Signals – Exercise XII: Naper Blvd and Plank Rd Learning Outcomes: • Analyze traffic crash crash and other engineering information • Select appropriate low cost safety and engineering Countermeasures

3. Traffic Signals – Exercise XII: Naper Blvd and Plank Rd Remedy of Naper Blvd & Plank Road Traffic Signal Northbound Naper Blvd at Plank Road

4. Traffic Signals – Exercise XII: Naper Blvd and Plank Rd Remedy of Naper Blvd & Plank Road Traffic Signal Southbound Naper Blvd approaching Plank Road At 280 feet back from Stop Bar

5. Traffic Signals – Exercise XII: Naper Blvd and Plank Rd Remedy of Naper Blvd & Plank Road Traffic Signal MUTCD Requires 460 feet of visibility Southbound Naper Blvd approaching Plank Road At 450 feet back

6. Traffic Signals – Exercise XII: Naper Blvd and Plank Rd Remedy of Naper Blvd & Plank Road Traffic Signal Southbound Naper Blvd at Ogden Av toward Plank Road

7. Traffic Signals – Exercise XII: Naper Blvd and Plank Rd Remedy of Naper Blvd & Plank Road Traffic Signal • The intersection of Naper Blvd with Plank Road was improved to traffic signal control in 1985 with the construction of Naper Blvd, a new 4 lane major arterial connecting south portions of Naperville, IL to the Illinois Tollway interchange to the north. • Plank Road is collector street with 5,500 ADT • Traffic crash experience averaged 15 per year with 6 to 8 serious injury crashes for the years 1985 thru 1991 • Traffic volumes on Naper Blvd started at 12,000 ADT in 1985 and grew to 28,000 ADT by 1991

8. Traffic Signals – Exercise XII: Naper Blvd and Plank Rd • Speed limit on Naper Blvd is 40 mph; 85th percentile speeds are 48 mph; speed limit on Plank Road is 35 mph. • Traffic signals were added to the north of this signal and a closed loop signal system was installed in late 1991. • Traffic volumes on Naper Blvd started at 12,000 ADT in 1985 and grew to 28,000 ADT by 1991. • Traffic crash experience averaged 15 per year with 6 to 8 serious injury crashes for the years 1985 thru 1991 • In early 1992, a multi-vehicle crash with fatalities was followed by two fatal crashes; 1993 had 4 fatalities, 9 serious injury crashes out of a total of 28

9. Traffic Signals – Exercise XII: Naper Blvd and Plank Rd • Visibility of the signals was a significant issue; southbound traffic could not see the far side indications until a point 280 feet from the stop bar; visibility of the northbound signals was slightly better at 350 feet. • Review of the engineering plans identified that the signal design was for tangent approaches; the actual conditions in the field were a reverse 35 mph 6 degree curve. • Signal heads were far side only with 12” sections and backplates • Review of Clearance Intervals (Yellow and Red) was carried out for 45 mph approach speeds and found to be consistent with ITE practice.

10. Traffic Signals – Exercise XII: Naper Blvd and Plank Road • What low cost safety countermeasures would you consider? • What is the safety effect (CRF) for each? Discussion

11. Exercise Questions?