MVRD Detector Accuracy Verification Test

Objective

To verify and demonstrate the functionality and accuracy of volume for the detector locations.

Prerequisites

Detector and cabinet installation must be complete.  Lane must be open to traffic.  ATMS inspector must be present during testing.

Test Equipment

A stop watch and traffic count board.

Success Criteria

Volume obtained from each detector for each lane of traffic will be within +/- 10 percent of each sample size.  Sample size will be ten minutes, or 50 vehicles, whichever comes first.  Traffic will be running at typical free-flowing speed and condition.

Test Instructions

1. Record the observed actual hand count volume and detector counts for ten minutes, or 50 vehicles, whichever comes first.
2. Record the volume of vehicles detected by the sensor over the test period.
3. Subtract hand count volume from detector count volume and then divide by the hand count volume. Multiply by 100 to get the percent accuracy.
4. Indicate pass if result is +/- 10 percent.
5. Adjust sensitivity and repeat if percent accuracy is out of range.

Volume Test Results
Lane #
Test Duration (min:sec)
Observed Hand Count Volume
Detector Count Volume (from Laptop)
% Accuracy = (100 x (detector count – hand count)/(hand count))
Pass or Fail (Pass if accuracy is < +/- 10%
Sensitivity Setting
Test Copmleted by (Installer’s Tester)
Date
Test Inspected by (ATMS Inspector)

MVRD Detector Accuracy Verification Test: Speed

Objective

To verify and demonstrate the functionality and accuracy of speed for detector locations.  Note that this test is applicable to Wavetronix Smart Sensor HD units that compute rolling average speed.  Also note that this speed testing is not required for freeway on/off ramps, only for mainline detection.

Prerequisites

Detector and cabinet installation must be complete.  Lane must be open to traffic.  CDOT Inspector must be present during testing.

Test Equipment

A calibrated radar gun, a stop watch, 2-way radios, and a laptop.

Procedure

1. Record distance L from radar gun to detector site.
2. Record offset O from center of each lane to radar gun site.
3. Compute the resultant angle theta ( = inverse tangent (O / L) ), which is the angle between radar gun beam and vehicle travel direction.
4. Compute cosine theta, which is the speed correction factor for the measurement angle.
5. Ensure that Detector unit is functioning, and that rolling average speed is being recorded.
6. Set the interval on the detector unit to 3 minutes.
7. Record the individual speeds of 16 consecutive vehicles using radar gun. If measuring consecutive vehicles is not possible, measure speeds for as many vehicles in the lane as possible, for 16 vehicles or 3 minute time period, whichever comes first.
8. Simultaneously to recording the 16^th vehicle, or completing the 3 minute time period, immediately record the current Detector Mean Speed as indicated at that moment by the Detector unit.
9. Compute the mean (Average) speed of the 16 vehicles, based on radar gun readings.
10. Compute the Modified Radar Gun Mean Speed ( = radar gun mean speed / cosine theta), if needed, if radar gun is not shooting head-on at vehicles.
11. Compare the Modified Radar Gun Mean Speed to the Detector Mean Speed. Pass if difference < 5 mph.  If test does not pass, adjust the sensitivity of the sensor and retest.
12. Repeat for each lane.

Speed Test Results
Lane #
Vehicle #	Speed form Radar Gun Display (mph)	Speed from Radar Gun Display (mph)	Speed form Radar Gun Display (mph)	Speed form Radar Gun Display (mph)	Speed form Radar Gun Display (mph)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Radar Gun Mean Speed (mph)
Cosine Theta
Modified Radar Gun Mean Speed (mph)
Detector Mean Speed (mph)
Pass or Fail (Pass if Modified Radar Gun and Detector Mean Speeds are within +/- 5 mph)
Sensitivity Setting
Does Controller Properly Record Occupancy?
Test Completed by (Installer’s Tester)
Date
Test Inspected By (ATMS Inspector)

MVRD Detector Accuracy Verification Test: Occupancy

Objective

To verify and demonstrate the functionality and accuracy of occupancy for the detector locations.

Prerequisites

Detector and cabinet installation must be complete.  Lane must be open to traffic.  ATMS Inspector must be present during testing.

Test Equipment

A stop watch, a traffic count board, and a laptop.

Success Criteria

Occupancy obtained from each detector for each lane of traffic will be within +/- 5 percent of each sample size.  Sample size will be three minutes.  Traffic will be running at typical free-flowing speed and condition.

Test Instructions

1. Record the observed actual hand count occupancy and sensor counts for three (3) minutes.
2. Record the occupancy of vehicles detected by the sensor over the test period.
3. Subtract hand count volume from detector count volume and then divide by the hand count volume. Multiply by 100 to get the percent accuracy.
4. Indicate pass if result is +/- 5%.
5. Adjust sensitivity and repeat if % accuracy is out of range.

Occupancy Measurements
# of Axles	Vehicle Length (Approximate)
2	20 feet
3	30 – 40 feet
>3	> 40 feet

Use the chart above to determine the number of axles by vehicle length.  Choose a populated lane and monitor the occupancy of the lane for three (3) minutes.  Use the chart on the next page to complete the test.

Occupancy Test Results
Lane #	Time Duration (min:sec)	Observed Occupancy Counts			Occupancy (from Laptop)			% Accuracy	Pass/Fail	Sensitivity Setting
		2 Axle	3 Axle	>3 Axle	2 Axle	3 Axle	>3 Axle	= 100 x (laptop – observed) / (observed)	Pass if < +/- 5%