Date	Amendment	By	Acknowledgement
11th March 2005	v2.2.2 Added the ability to cope with low-traffic flows	Richard Lord	Suggested by Greg Collins
14th April 2004	v2.2.1 Minor adjustment to rounding procedure, so that this model produces the same Basic Noise Levels as the examples in CRTN Annexes. Addition of Road Surface 'help' button, to state that impervious texture depths are assumed to be zero.	Richard Lord
28th January 2004	v2.2.0 The combined segment total is now calculated.	Richard Lord	Suggested by Gordon Smith.
28th October 2003	v2.1.0 Bug-fix The Surface corrections for Impervious calculations at speeds greater than 75 km/h were not being applied correctly. Required explicit setting of variable to zero. Calculation of average path height from source-receiver height difference was incorrect. Problem lay in the reading of the variable from the textbox - required conversion to Number().	Richard Lord	Thanks to Gordon Smith.
28th January 2003	Model re-written in JavaScript for extra compatibilty. v2.0.0	Richard Lord
30th August 2002	The text in stage 5 was altered to avoid confusion of adding the facade correction twice	Mark Jiggins	Thanks to Graham Rock of Graham Rock Acoustics, Taunton, U.K for reviewing the model.
2nd Nov 2001	Improved the text of the message that pops up when choosing 'estimated from road class'. Included a gradient correction check box and help button. Altered the correction for road surface to include an option not to correct for it. Fix the divide by zero problem with the barrier calculation. Implemented rounding to the nearest 0.1dB for each of the calculation stages as specified by CRTN. Compared more calculated results with the worked examples given in CRTN.	Mark Jiggins
10th Sept 2001	Incorrect correction for gradient: '- GradientCorr' changed to '+ GradientCorr'	Mark Jiggins	Thanks to Werner Kohl at www.woelfel.de for finding the error.