Traffic monitoring

Why do we collect data?

We monitor many aspects of the city's transport to:

• identify trends and develop models
• assist with planning for the future
• assess changes in behaviour
• assess the impacts of new developments
• help secure resources to improve the transport system in Bristol
• measure progress towards achieving targets, especially for the Joint Local Transport Plan
• fulfil statutory requirements in support of the Joint Local Transport Plan and as part of our responsibilities under the Traffic Management Act 2004.

What data do we collect?

We follow an annual monitoring programme, but also carry out data on an adhoc basis for specific projects.

The annual programme includes:

• Cordon, river screenline and link counts which measure traffic flows in, out and across the city.
• Surveys to measure the progress of Greater Bristol's Joint Local Transport Plan (JLTP).
• Counts for the Department for Transport as part of their national rotating census programme.
• Pedestrian and cycle surveys.
• An annual rail survey.
• Manual traffic census.

Some of the survey sites have been monitored for many years.  These can provide useful information about seasonal and annual variations. Data is also used to help create models of transport flows throughout the city.

Data on road accidents and casualties are available from the Road Safety Team.

Report of surveys

The Report of Surveys 2008 collates data from most counts and provides an overview of traffic changes over the past 15 years.

The report includes data and analysis to show travel patterns (by time and season) and vehicle volumes for all modes.

A summary of the key findings in the 2008 report has been produced and can be viewed below.

How do I request traffic data?

As well as the Report of Surveys that we publish, anybody can request a copy of traffic data that we hold. This existing data is provided free of charge to students and not-for-profit organisations on request. For other individuals and organisations, and bespoke surveys, a charge will be made.

If we don't have any appropriate data for the locations that you require, we can carry out a traffic survey on your behalf. A charge will be made for this service, see charges below.

To make a request, see the contact details section below.

What charges are made?

These are suggested costs. For a detailed quote, please contact us.

Data is usually provided as Excel files or in print format.  We may be able to provide other formats on request. Please note that this data is not to be distributed further without prior permission from us.

Existing Data

Bespoke Surveys

Manual Traffic Surveys vary in price, depending on size, location and numbers of staff and equipment required.

What types of data and collection methods are used?

Automatic counts

There are several different types of automatic counter. The council currently uses either sub-surface loops or radar counters to carry out Automatic Traffic Counts (ATCs).

ATCs are generally used to measure:

• Unclassified volumes of all vehicles including annual average daily traffic (AADT).
• Vehicle speeds (it should be noted that these counters cannot be used for enforcement purposes as they do not record registration details).
• Volume of cycles and pedestrians.

We have installed a number of permanent ATC sites around the city and also regularly pus up temporary ATCs.  For example:

• To monitor traffic at events.
• To monitor the effects of changes to the road network.

These are usually radar or tube counters.

Manual counts

These can be tailored to individual surveys. They are usually 12 hour surveys, but timings can be varied where necessary. Types of count include:

• Manual Classified Counts (MCC), for example the volume of traffic classified by vehicle type.
• Turning counts at junctions, or more detailed origin and destination surveys.
• Queue length surveys.
• Pedestrian and cycle usage surveys.
• Private transport journey-time surveys.
• Public transport journey-time and punctuality surveys.
• Public transport passenger counts and user surveys.
• Parking surveys (including headway surveys) .

Video surveys 

Newer technologies using video can provide more accurate monitoring of vehicle movements. For specific projects, we have used contractors to provide temporary counts using video equipment.  For example Automatic Number Plate Recognition technology can provide detailed information about whether improvements to a junction have improved journey times. Our Traffic Studies Team is currently considering how to make best use of such equipment.

Interviews and user surveys

This type of survey is sometimes needed to gather more detailed information about behaviour or feedback on services. Types of survey include:

• Roadside interviews.
• Public transport user surveys - onboard or at stations / stops.
• Face to face interviews.
• Postcard surveys.

Contact us

When contacting us please provide as much information as possible about the data you require, at a minimum including specific locations, dates and type of information you require. Contact details to top right.