Experience implementing adaptive signal control systems in Colorado.
Woodland Park Corridor, Colorado, United States
Greely, Colorado, United States
Adaptive Signal Timing Comparison Between the InSync and Quictrac Adaptive Signal Systems Installed in Colorado
Summary Information
This project evaluated the benefits of installing InSync and QuicTrack real-time adaptive signal control systems installed on two corridors in Colorado. The InSync system was installed on 10th Street (US 34 Business) in Greeley, and the QuicTrac system was installed on US-24 in Woodland Park. The Colorado DOT collected traffic data before and after each system was activated in early 2012.
The InSync system was adapted to existing signal controller hardware at 11 intersections on a four mile section of the 10th Street corridor. The QuicTrac system was adapted to existing signal controller hardware at eight intersections on a 3.65 mile section of US-24. A high-speed communications network connected all intersections to a central system that enabled operators to control the systems and view performance data and camera images remotely.
A benefit cost analysis was completed to determine how long each system would take to pay for itself. Before and after data were collected to evaluate performance and the following factors were used to calculate benefit-to-cost estimates:
- Travel time
- Fuel consumption
- Side-street delay
- Design and engineering cost
- Adaptive system cost
- Detection/communication upgrade cost
- Construction/installation cost
- Staff time spent for design, installation, and training
- Expected annual maintenance
To calculate the cost savings in terms of reduced travel time and fuel consumption, the total travel time (vehicle-hours) was multiplied by the value of time and vehicle occupancy values for the area and the fuel consumption savings were multiplied by the average per gallon fuel cost for the area. The value of time for both corridors was estimated at $15.00 per person per hour, average vehicle occupancy for both highways was estimated at 1.3 people per vehicle, and the average fuel costs were estimated at $3.65 per gallon in Greeley and $3.50 in Woodland Park. Annual benefit-to-cost ratios were computed based upon a 350 day year (250 weekdays and 100 weekend days). Days with non-typical travel volumes (holidays, events, weather, etc.) were omitted from the analysis.
FINDINGS
The tables below excerpted from the source report show significant annual savings to both corridors. The 10th Street analysis predicted a user savings of more than $1.326 million dollars, and the US-24 analysis predicted a user savings of almost $900,000 per year.
10th Street Annual Benefit (combined weekday and weekend)
Measure of Effectiveness | Daily Benefit | Daily Cost | Annual Cost |
Travel Time (vehicle hours) | 207 | $4,034 | $1.412 million |
Fuel Consumption (gallons) | 122 | $445 | $156,000 |
Side-street delay (vehicle hours) | -41 | -$805 | -$282,000 |
Annual Maintenance (estimates indicated 1163 hours saved per year at $35 per hour) | $115 | $40,700 | |
TOTAL | $3,789 | $1.326 million |
US-24 Annual Benefit (combined weekday and weekend)
Measure of Effectiveness | Daily Benefit | Daily Cost | Annual Cost |
Travel Time (vehicle hours) | 191 | $3,730 | $1.305 million |
Fuel Consumption (gallons) | 149 | $522 | $183,000 |
Side-street delay (vehicle hours) | -87 | -$1,698 | -$594,000 |
Annual Maintenance (estimates indicated 130 hours saved per year at $35 per hour) | $12.86 | $4,500 | |
TOTAL | $2,567 | $898,000 |
The table below excerpted from the source report provides an overall summary of benefits and costs.
InSync System | QuicTrac System | |||
---|---|---|---|---|
Category | Actual Project | Minimal Project* | Actual Project | Minimal Project* |
Number of Intersections | 11 | 8 | ||
Daily cost saving (corridor) | $3,789 | $2,567 | ||
Annual cost saving (corridor) | $1.326 million | $898,500 | ||
Install costs (corridor) | $905,500 | $375,000 | $176,300 | $162,400 |
Daily cost saving (per intersection) | $344 | $321 | ||
Annual cost saving (per intersection) | $120,500 | $112,300 | ||
Install costs (per intersection) | $82,300 | $34,000 | $22,000 | $20,300 |
Benefit-to-cost ratio | 1.58 | 3.79 | 5.64 | 6.10 |
10-year projected savings | $4.2 million | $4.7 million | $2.8 million | $2.8 million |
20-year projected savings | $9.2 million | $9.7 million | $5.7 million | $5.7 million |
AADT (Colorado DOT data near middle of corridor) | 26,500 vehicles | 22,500 vehicles | ||
Daily cost saving per user | $0.14 | $0.11 | ||
Annual cost saving per user (assume 350 day use of road) | $49.00 | $38.50 |