9-1 low cost safety improvements practitioner workshop exercise c – session #9

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LOW COST SAFETY IMPROVEMENTS

Practitioner Workshop

Exercise C – Session #9

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Exercise

Learning Objectives:

1. Analyze traffic crash crash and other engineering information

2. Select appropriate low cost safety and engineering Countermeasures

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Traffic Signals – Exercise XII: Naper Blvd and Plank Rd

Remedy of Naper Blvd & Plank Road Traffic Signal

Northbound Naper Blvd at Plank Road

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Southbound Naper Blvd approaching Plank Road

At 280 feet back from Stop Bar

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At 450 feet back

MUTCD Requires 460 feet of visibility


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Southbound Naper Blvd at Ogden Av toward Plank Road

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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

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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

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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.

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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

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Case Study J: Remedy of Naper Blvd & Plank Road Traffic Signal

Signal Timing /Coordination and Visibility Improvement

Additional Supplemental Near-Side Signal

Northbound Naper Blvd at Plank Road

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Signal Timing /Coordination Visibility Improvement

Advance Warning Sign with Yellow Flasher


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Signal Timing /Coordination and Visibility Improvement


Southbound Naper Blvd at Plank Road

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At 450 feet back from Stop Bar

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Southbound Naper Blvd at Ogden Av toward Plank Road

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Signal Timing /Coordination Visibility ImprovementAdvance Warning Sign “Be Prepared to Stop” with “When Flashing” Plaque with Flasher tied to Controller

Northbound Naper Blvd approaching Plank Road

“After” Crash experience is 8 crashes per year or less for 1996-2002 with no serious injury or fatals

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Exercise

Learning Objectives:

1. Analyzed traffic crash crash and other engineering information

2. Selected appropriate low cost safety and engineering Countermeasures

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Questions?

Exercise

9-1 low cost safety improvements practitioner workshop exercise c – session #9

Documents

construction of naper

plank roadat

plank rdvisibility

traffic volumes

traffic crash crash

plank rdspeed limit

traffic signal control

adt traffic crash experience