We have monitored traffic levels and growth in West Sussex for a number of years. This data helps us understand transport problems and assists us in policy development.
Traffic data is collected by two main methods, both of which are outlined below.
Permanent automatic traffic count sites
Over 160 permanent count sites provide a consistent record of traffic flows. The data is collected using inductive loops cut into the carriageway.
The counter sites are capable of measuring traffic flow and speed. The flow data can also be classified by type of vehicle.
Data from a subset of the permanent counters is monitored to provide an overview of the traffic situation in the county. These sites allow us to compare and analyse traffic flows across the county year on year.
Traffic flows are measured 24 hours a day throughout the year, from which average annual flows are calculated, referred to as the 'annual average daily traffic'. An indication of changes in traffic levels can be provided from 1990 to the present day.
Temporary automatic traffic counts
Temporary automatic traffic counts are undertaken by pneumatic tubes across the road that measure flow and traffic speed. These counters can classify vehicles into various groups, such as cars, buses and heavy commercial vehicles. They are usually installed for one week.
Traffic data website
Volume, speed and classified traffic data is available to view and download from our traffic data website.
Data from permanent automatic traffic counter sites is available, together with data from some of the temporary traffic survey sites (which are usually limited to one week of data).
To access the website you will need to set up an account and agree to the terms and conditions.
Instructions on how to use the website are available in the help section. This includes how to select sites and export data to Microsoft Excel.Traffic monitoring database (external link)