odds and the power of the state and federal highway authorities with only one objective and that is to make the defendants follow their own established protocols and guidelines in the southwest denver metro area now the size of the scope of the c four hundred and seventy dollars project is considered a large corridor project and that's an important distinction for the present in this case under the national environmental protection act or need there was a in two thousand and fifteen an environmental assessment that was issued for the project and it was required to include an analysis of potential traffic noise impacts for federally aided highway projects such as this nepa requires implementation of state specific guidelines that must comply with federal guidelines now relevant to this case adopted state specific noise analysis and abatement guidelines which are referred to as the two thousand and fifteen colorado guidelines and those guidelines were approved by the defendant better highway administration and indeed the introduction to those state and federally approved guidelines specifically states that they are based on currently accepted best management practices and procedures used by veteran straight state transportation agencies and that they will be subject to review every three years honor that's a that's a very good question and the the key is the language is mandatory in multiple places and st of all it is state specific guidelines which the waves and so that they take precedence over federal guidelines but more importantly the two thousand and fifteen guidelines themselves refer to this user's guide as the protocol for the use of validating traffic noise models and seat out projects and indeed in section three point three of those guidelines it states that the two thousand and six user's guide represents in fact what it specifically calls the standard validation practices about that is it at least ambiguous if you have the two thousand and six users guide that expressly refers to itself as recommendations and you have a language  obligated c to use all of the terms in the user's guide even though it had described itself as recommendations in other words you have an anomalous situation you have clearly recommendations and that you have documents that are referring to in the in the in the two thousand and fifteen guidelines and that seems to create an ambiguity in my wrong about the well your honor i don't see that ambiguity what i see is that the guidelines included that user's guide as an appendix and i believe the appropriate way to look at this is that the guidelines should be read as a whole entire document and those that user's guide is part of the entire die from you have to read it all together and i think it is a fair characterization to say that the guidelines adopted all of those recommendations by including it not only in nine years now to clarify any ambiguity there so i would say to the stat that it could be deemed ambiguous i think that needs to be held against the people who drafted the document an established system and again these are establishing specific protocols and they have specific protocols and they and they set out different scenarios or medium sized projects or large side projects so again these are just i don't think they can be just deemed as recommendations and  document is one entire docking at the covers and this entire process is specific technical scientific process measurements that were taken in this case were actually conducted here and i would submit if they were truly irrelevant if the if the requirements that they are now saying are irrelevant not applicable remnants whatever you want to use from all of their assertions they had the duty to correct that and they never did their own never did over nine years or the post rationalization if those were two of the i think the regulatory history is the document that was approved by the current department of transportation and again approved based on a four year scientific study the two thousand and six user's guide that's at issue here was developed over a four year colorado state specific study chemical scientific process that was included there they included that that was the state of the art in two thousand and eleven they chose to do that and they've chosen to keep what the defendants now want you to believe is that they put that in there and they've kept it in there year after year after year but they didn't really need to it doesn't really serve any purpose even though they refer to it explicitly themselves as the standard validation practice is in command their action on this specific point and i mean so why why there are problematic two questions was unnecessarily problematic to include the guy or what it's worth why and you say any ambiguity is on on c dot a why why is it on c that when r ce any under it is are they acting in an arbitrary unreasonable fastened so let's assume there was an ambiguity well if they question is not they have to do deem this appendix a relevant or not they aren't claiming it is a relevant are they even in the clarence statement they're not i mean it's irrelevant they're just claiming that it has certain driver for purposes of this case they have effectively taken the position that it is irrelevant because with regard to this case a large quarter project they have chosen to ignore the specific requirements set forth for large quarter projects and said we're only going to look at a different validation that then which is only applicable under these guidelines to medium sized projects so in effect they are ignoring that and you know picking and choosing what they want to use and what they don't want to use so that that's the reality of what they've done but again in order to accept the defendant's positions in this case you have to essentially believe that these knowledgeable scientists essentially put in a requirement there that they are choosing not to follow and not to ignore and they have determined the used up it can choose whatever they want whenever they reasonable way to thread the needle then why is there of while a sion of their obligation as an agency that's my question let's assume it is them let's assume it's not clear if they come up with a reasonable way to discern how to deal with the tension between recommendations and the language in the two thousand and fifteen document if they come up with a reasonable way to say i'll take corson's of the appendix e but not all of it why is that why would that encourage an arbitrary matter of the system and why would that be seen an arbitrary matter  honor under the applicable standard the defendants are required to consider all of the relevant facts and there or if they are required to offer an explanation as to why that happened now in this instance that the whole crux of this case is whether they consider all of the relevant facts and i would submit in this case they never did they have a long term noise data measurements that they took they've just never validated this project with that information all we're asking them to do is to do what they're required to under these under these states pacific requirements that they created and just do the analysis it's sitting right there for them and their explanations are by not looking at the relevant data not following that they have the sensually acted arbitrary by by failing to follow their own guidelines and  the explanations of threading the needle isn't the standard the standard is have they consider all the evidence and have they provided a plausible it's not explanation in this instance i would submit they have not supplied the only explanations are post hoc rationalization they run counter to the evidence and therefore are so implausible that they cannot be considered the product of agency expertise and are therefore arbitrating to produce this and should be rejected colorado department of transportation now here the district court did correctly conclude that the agencies have complied with the procedural requirements of need in the this that the use of long term noise measurements and model validation is not legally required as the district court here concluded the agency's decision to use the short term measurements to validate a noise model capricious under the highly deferential standard of the a p a that flies here and that rational decision was consistent with the two thousand and fifteen colorado noise guidelines longstanding practices c dot and current industry standards and it was based on the exercise of technical knowledge and discretion of the noise analyst on this project a matter is within the agenc expertise to which the courts routinely defer now the record here supports the recent illness of the agency's decision to use short term measurements and validate the model all the parties agree that the the state follows for the noise analysts here and that is what the c dot did here they collected noise levels and traffic data for one thousand and twenty minutes at two different times that their team representatives locations in the study area measurements or take it at any time however is best to measure when the traffic is relatively free flowing at or near the posted speed limit was here we have a highway where those short term measurements were taken when it sample is usually statistically accurate enough to attain a good measurement but sample times of thirty minutes much may be necessary but here it wasn't necessary because it actually validated after the c dot plug those numbers that it at that it that it based on the field data that they had read that they had collected and measure it against the model results came within the margin of error which is three decibels and therefore they validated and makes sense because noise measurements and traffic data are converted into a one hour time frame for the model and so because one hour equivalent sound level is the standard measure of time and noise meter that measures sound for fifteen minutes for ten to twenty here is adjusted and so there's just no reason to have a need a long term measurement validate the model here and collecting the record is clear that collecting that data using the short term time frames is the industry standard and certainly consistent and you don't warm practice of speed up for many years and it also i consistent with federal highway guidance on highway traffic noise analysis now the coalition here though relies only on the two thousand and six user's guide to argue that long term measurements are required but i just holmes pointed out the guide on its face in several areas including the talking about the validation to the models it's very clear that they that the guide only provides full recommendations and that these are just and section four levels of something to think about if but they are not actually required and if the agency planes in numerous places including the declarations the texts the the purpose of the guides were limited here and it was st of all to provide guidance to the noise analysts and the input up adjustment  actors were paid and the model that it was the only place that time in the beginning where this information was available to noise analysts these models and be quite complicated and so this is to help with this new model and nd of all to provide additional practices to consider when a model fails to validate that doesn't apply here because the model did allocate well as if you credit the explanation but if you simply guide even though it on its face was recommendations because it was incorporated as the protocol buzzword big answer on her and i want to make sure that what we're saying is that no we should about suit way sions where the bible does not validate and then it refers to the user's guide as perhaps providing some different ways that the ways expert can come up with to help it to help it validate the model and in fact it's not the only thing it references that statement actually references also a traffic noise model frequently ask questions and it provides a link and if you look at that link that link provides different adjustment factors inputs models and that sort of thing that helps a noise analyst be able to to do some the model does not validate then the what the noise analyst has to do is go back and do correction factor or figure out different inputs or explain why didn't or it has to take more measurements and that point what what that statement as as the declaration as ethnic it's been explained goes to provide certain other or other options that and analysts might be able to do i see that my time is running down i do want to allow the state council to be able to to present arguments so if there are no further questions that's fine