Motorists will be flagged down by police officers in Shrewsbury over the next month as part of a major traffic survey.
The study has been set up by Shropshire County Council's consultants, Parkman, working in partnership with the Highways Agency.
The information gathered will form part of a major review of travel patterns in Shrewsbury which started in September.
It will be used to create a computer model of traffic movements which will be used to plan future transport schemes in and around the county town, including possible options for a North West Relief Road.
'Minimise delays and disruption'
"Using modern technology we are able to create an accurate computer simulation of journeys in Shrewsbury; however, the accuracy is dependent upon the collection of quality information," said Martin Withington, Shropshire County Council principal transport planning officer.
"It is therefore very important that the public help us with this aspect by taking part in the survey and providing the information needed.
"We appreciate that the survey will result in some inconvenience to travellers but every effort is being made to minimise delays and disruption."
Mr Withington added: "The co-operation of the public is vital to the success of the survey and the results will provide important information to help us plan future transport investment in Shrewsbury."