Motorists caught in delays caused by traffic surveys across Norwich have been told the information they provide is vital to future transport plans for the city.

Norfolk County Council is conducting its traffic census throughout November and a spokesman admitted there had been complaints about the exercise being carried out at busy times.

Motorists are either being asked on-the-spot questions about the details of their journey or are being asked to fill in pre-paid postcards to be later returned by post.

This is the first major survey of traffic in and around Norwich since 2006 and the information provided then it now considered out of date.

Graham Plant, the county council's cabinet member for planning and transportation, said: 'We last carried out comprehensive surveys of this sort more than five years ago, and that data now needs updating. Accurate information is vital as we continue to develop our travel and transport plans for Norwich and its surrounding area.'

The surveys are being conducted from Mondays to Thursdays in undisclosed locations in Norwich and its surrounding areas in order not to distort the results.

Around 30 surveys will be carried out until the end of this month with two to three different parts of Norwich being surveyed each day.

Council spokesman John Birchall said: 'A lot of people have complained about us conducting these surveys at busy times – but this is the most crucial time to collect traffic data to understand how it behaves at peak times and to support any future plans to make changes to any roads or junctions.'

The aim of the surveys is to capture traffic flow patterns that can be expected on a typical weekday.

Fridays and weekends have been deliberately left out due to the nature of the traffic being so different from normal weekdays – although 64 automatic counters have been positioned to monitor the traffic throughout the week.

While these continually record the traffic numbers they do not disclose where the traffic has come from, or where it is going hence why on-the-spot surveys and postcard surveys are being implemented on some motorists' journeys.

Motorists are not obliged to complete and return the pre-paid postcard survey handed to them at the side of the road, but they are instructed to comply with on-the-spot surveys under instructions from traffic officers.

The data collected will help form the basis for traffic models which can be used to help understand the possible impacta proposal might have in the early stages of planning.

Mr Birchall added: 'Without properly sampling the traffic and conducting these survys we would not be able to accurately Produce traffic models. This depends on the quality of the data - in order to make improvements we need the up to date information to model the effects – we can't assume traffic behaves in the same way as it did six years ago.'

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