What are the accuracy levels of Idris Products?

Data Recording: DR200 & DR400 Ranges
The DR200 range are basic, profile only, data collection classifiers tailored to requirements where congestion is not experienced. The DR400 products offer a range of classifier capabilities which deliver consistent results in both free flow and congested traffic.

Data recording requires classification accuracies in the order of 90% to 99% due to the aggregate nature of the data analysis. Subject to the classification table, Idris products meet the following accuracy specifications:

Count accuracy for DR215	>99.5% in freeflow traffic
Typical Class accuracy for DR200 range	>85% in freeflow traffic

The DR400 range are high end data collection products with the ability to work in congestion. DR405 is a length only based classifier, which meets the UK HA specification for shadow tolling.
DR410 is a length & profile based classifier.
DR420 is an axle based classifier used to enhance detection and classification capabilities using patented axle loops.

Within their classification table specification, each of the DR400 range, meet the following accuracies:

Count accuracy for DR400 range	>99.9%
Class accuracy for DR400 range	>95%
Typical class accuracy for DR420	>95% (99% is achievable in most installations)
The DR400 range has no statistical bias

Deep Loops for Data Collection
Idris uses enhanced loop detectors to obtain high levels of detection and classification accuracy. Further refining the sensitivity of Idris' enhanced detectors has enabled both the main and axle loops to be placed 50mm (two inches) or more below the surface of the road - previous depths for axle loops were 20mm (three quarters of an inch). There are currently two types of detector which have been tested and Idris-qualified to be used with deep axle loops. These detectors are the TD724ID, supplied by Nortech International, and the Group 7 224 supplied by Peek Traffic.

Testing for accuracy levels is on going. Please contact DCS for the latest updates.

Idris Profiling: SF700 Range
The SF700 was commercially exploited as a Peek Traffic product - Prism. This improved product is now currently available from Drakewell Computers, known as GEM. A profiling product can be used to activate bollards, traffic lights or VMS signs without the need for on-vehicle devices by using inductive loop profile technology.

Bus classification accuracy:	>95% after tuning
Count accuracy:	99.9% in free flow traffic
Count accuracy in congestion:	99.9% in congestion

Speed Detection: SF600 Range
The Idris speed detection algorithms were validated in 2009 at Bruntingthorpe Proving Ground, Leicestershire, UK. Speeds between 20mph (32kph) and140mph (225kph) were validated.

The validation showed the Idris Speed Detection Algorithms meet and exceeded the UK's Home Office Approval specification as well as meeting the accuracy specifications stated by DCS.

+/- 2kph for speeds below 100kph (62mph)
and +/-2% for speeds over 100kph (62mph)

In addition the measurement accuracies were well within the tolerance requirements of the HOSDB Publication No 15/05, listed as:

Positive error not greater than 2mph (or 3%, over 66mph
(Positive error not greater than 1.2kph (or 3%, over 41kph)

Negative error no greater than 5mph (or 10%, above 66mph)
(Negative error no greater than 3.1kph (or 10%, above 41kph)

Tolling: AT600 & AT700 Range (includes AVI correlation)
Tolling applications are typically looking for detection count accuracies in excess of 99.9% with commensurate classification accuracy.

Irrespective of weather conditions and in live traffic environments, the Idris axle detection technology consistently achieves the accuracies required by tolling agencies from manual to open road tolling lanes including all electronic toll collection.

Count accuracy in free flow:	99.99%
Count accuracy in congestion:	99.9%
Axle class accuracy in express lanes:	>99.5%

For specific axle based tolling classification accuracies >99.5%, please refer to DCS for confirmation. Higher levels of accuracy are achieved after regional tuning.

Buses after tuning:	95%
Twin Rear Wheels:	85% (Improved after tuning)
Length accuracy:	+/- 5%
Speed accuracy for standard tolling products	+/- 3.2kph (2mph) up to 100kph (66mph) +/- 3% above 100kph (66mph)
Overall tolling accuracy: 99.5%	Typically: 99.7%
Congestion with normal traffic mix;
Normal congestion (am & pm stop-go traffic)	Classification accuracy >99.5%
Free flow with normal traffic mix:	Classification accuracy >99.7%