Evaluating Alternative Operations Strategies to Improve Travel Time ...

SHRP 2 L11: Final Appendices
Work Zone Management
• Safety: The Illinois DOT enhanced work zone safety on I-55 by deploying an automated traffic control system that posted traffic
information and enforcement updates (number of citations issued) on dynamic message signs located upstream of the work zone
(1).
A portable speed detection and warning system placed upstream from an I-80 work zone decreased the highest 15% of vehicle
speeds by about 5 mi/hr as vehicles approached the work zone lane merge area in Nebraska (2).
• Mobility: An automated work zone information system on a California interstate greatly reduced traffic demand through the work
zone resulting in a maximum average peak delay that was 50 percent lower than expected (1).
A modeling study indicated that work zone delay messages reduced maximum traffic backups by 56% and contributed to a 55%
reduction in traveler delay in North Carolina (2).
Modeling data showed that an automated work zone information system deployed on I-5 near Los Angeles contributed to a 4.3%
increase in diversions and an 81% increase in average network speed (3).
• Efficiency: Traffic speed data in the Minneapolis/St. Paul collected at two interstate work zones showed that when portable traffic
management systems were deployed, work zone traffic volumes increased 4% to 7% during peak periods (1).
Based on a review of work zone ITS deployments from 17 states, the estimated benefit-to-cost ratio ranged from 2:1 to 42:1
depending upon conditions and assumptions (4).
The use of ITS for temporary construction zone management in Lansing yielded a benefit-to-cost ratio of 1.97:1 and a net benefit
of $4,874,000. The benefit-to-cost ratio was calculated by dividing the benefits of the system ($9,874,000) by the overall cost of the
deployment ($5,000,000) which included $2,500,000 for opportunity costs (5).
• Customer Satisfaction: A survey of local residents near Smart Work Zone systems found that over 95% would support use of these
systems in the future in North Carolina (1).
Strategy: 5.1. Geometric Design Treatments
Category: 5. Infrastructure Improvements and Optimization
TREATMENTS AND IMPACTS:
Bottleneck Removal (Weaving, Alignment)
• Safety: Bottleneck removal on I-15, north of the Seattle central business district, resulted in an accident reduction of 39% (43).
ADDITIONAL DESCRIPTION AND QUANTITATIVE BENEFITS OF TRAVEL-TIME RELIABILITY STRATEGIES Page F-32