For the first time in over 25 years working with TRANSYT models I am being asked to validate a TRANSYT model by a local authority. I have resisted this and will continue to do so but the local authority is sticking to its guns at the moment.
In the TRANSYT user manual there is no mention of calibration and the only mention of validation is in regard to the saturation flows (which is fine as we will just ensure that we provide robust values).
I've had dealings with many many authorities and the HA and have never been asked to validate a TRANSYT model.
Many years ago I tried to validate a signalised gyratory against the measured queues and it was a nightmare task in trying to guesstimate the parameter values such as the cost of queuing on a link by link basis. I did eventually manage to achieve this but then when I ran that model over the other peak period it was clear that I would have to start all over again - which made the whole process a nonsense and hugely time consuming.
Has anyone else had any similar requests for TRANSYT model validation? If you haven't can you mention one or more of the local authorities that have and (just as importantly) haven't.
I wrote to JCT at the beginning of December and they said that Barbara would be interested in commenting but was about to go to New Zealand to install the first signalised gyratory over there. I will contact JCT again but I will still be interested in any views from local authorities and consultants.
I've worked with TRANSYT and TRANED presentations for decades and can confirm I've never come across a validation request before but LA traffic modelling skills must vary greatly these days. Indeed I'm sure some authorities will likely have little to no expertise depending on their size. Hence some LA transport officials may be more cautious with complex traffic models with lots of data attached to them. Generally, where the skill is present within the authority, an assessment of the data/relative results will be carried out and consultation will ensue to possibly correct/alter some of the data, refine the model etc etc. A formal meeting will probably follow and the TRANSYT model will be formally accepted.