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Hertfordshire County Council

Transport and accident data

Traffic data and charging policy

Traffic and transport data reports (TTDR)

Traffic and transport data reports are produced annually, summarising the latest available information on:

  • traffic levels and growth
  • congestion and air quality
  • how people choose to travel
  • sustainable transport and future improvements.

The report contains interactive maps for further information, please visit

Hertfordshire Highways Traffic Webmap

Hertfordshire Highways Reliability

Previous traffic and transport data reports


Traffic data requests

The road traffic database contains traffic data for roads in Hertfordshire. It has been created using both electronic and manual traffic counts.

Take a look at a map of traffic count data.

For all enquiries, contact:

01992 658323

We charge a fee for data supplied to organisations. We determine the fee by the type of data and the number of datasets requested. More about our data charging policy (PDF 131Kb).

Accident data

Casualty factsheets

Casualty factsheets are produced annually, summarising the most up to date information about traffic accidents and casualties in Hertfordshire.

Contact us to see casualty factsheets from previous years.

Hertfordshire Road Casualty facts 2020 (PDF 579KB)

Accident data requests

The road collision database uses accident data (STATS19) supplied by the police. In some cases, there may be restrictions on the accident data that can be supplied.

For all enquiries, contact:

01992 658338


01992 658339.

We charge a fee for data supplied to organisations. We determine the fee by the type of data and the number of datasets requested. More about our data charging policy (PDF 131Kb).

Mobility surveys and evidence packs

Town Evidence Packs

Hertfordshire County Council have created Town Evidence Packs to help understand local movements, interactions and characteristics around a specific town. They can help developers with pre-application work and can support decision making and funding opportunities. Evidence Packs have been created for the majority of Hertfordshire towns and include information on: origin and destination movements, trip patterns by mode of transport, journey times, congestion, demographics, economics and accident data. Each pack costs £750 and can be purchased by contacting the team via the contact details noted below.

Executive summaries have been produced for each of the Evidence Packs and are available to download free of charge:

Town Evidence Pack Executive summaries


Contact us...

01992 588614


Hertfordshire county travel survey

The Hertfordshire county travel survey recorded how a large number of our residents travel. 

The results of these surveys have helped us to improve our existing transport structures and have assisted with developing new schemes.

For details of the Appendix D of the survey report, it is available upon request at the following email:

Attitudinal survey

Hertfordshire County Council conducted an attitudinal survey to collect opinion-based data across the county. This survey is about public opinion and perception in terms of some key perspectives such as Transport use, Infrastructure, Barriers to walking and cycling and Perceptions of initiatives.

Speed indicator device data

Flashing speed signs - or Speed Indicator Devices (SIDs) - are used by roads across Hertfordshire to remind drivers of the appropriate speed for the road they're on. Most of the SIDs are funded by county councillors using their Highway Locality Budgets. Some have been funded by third parties such as parish councils.

The signs retain the captured speed of the first 200,000 vehicles that pass. We don't routinely collect this data. In order for us to download the data, a 3rd party highways engineer needs to visit the device to collect the raw data, which is then passed to another 3rd party organisation to process it into a usable format.

Because we need to use external organisations, we face a charge each time this process is undertaken to collate and format the data.

To download the data from a particular SID, the charge is £150.

To access data that has already been downloaded, the charge is £15.

For new data from a SID (the SID memory is cleared and new data downloaded after a set period), the charge is £300.

For all enquiries, contact...

01992 658323

Please note:

  • SIDs record vehicle volumes and speeds.
  • Data starts recording from first installation (or when it's reset) until the maximum number of records is reached.
  • Until the data is downloaded and processed, the number of records and the period covered is unknown.
  • The payment covers the retrieval and processing of any held SID data, plus the issue of an Excel spreadsheet (showing speeds and volumes by each hour on each day), plus 2 graphs showing the data in chart form. No further data will be supplied in any other formats.
  • If the data cannot be downloaded then the fee is still payable.
  • We don't guarantee the accuracy of the data. The SID data, alone, would not be the sole basis to consider additional requests for council services.

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