Rural Routine Monitoring and Annual Average Daily Traffic (AADT)
These are a mixture of junction turning counts and simple two way surveys on straight links of road. Surveys are conducted 7am to 7pm twice annually, one day in a neutral month and one day in a summer month (late July or August), which allows for any seasonal variation.
Rural screen line surveys are similar to the above but are counted every year and help to indicate traffic growth.
These surveys use a standard 10-category classification is used to identify vehicles.
Data from the two manual, 12-hour surveys (7am to 7pm) is factored up using nationally derived criteria in a special software programme to obtain an average daily flow for a section of road.
This is known as an Annual Average Daily traffic (AADT) flow over 24 hours. This is the average traffic flow you would expect on a section of road over24 hours and is the normal manner of expressing traffic levels in the UK.
This information has many uses, one of which is assisting with the processing of Deflectograph surveys to project the future life of a carriageway.
Permanent Automatic Surveys
Lincolnshire County Council currently operates CA Traffic’s Loop Profiler-type counters for its long term permanent monitoring work. These are battery powered machines sometimes supplemented by solar panels or mains supply.
Automatic Traffic Counters
The counters are installed in road side cabinets and use inductive loops in the carriageway to detect vehicles. Each site has four loops in the carriageway, two per lane and can classify vehicles.
Automatic Cycle Counters
These counters use special loop detection systems, for cycle routes. Cycle counters are battery powered and may have a solar panel fitted. Some sites are fitted with telemetry, otherwise they are visited on a monthly basis.
Requested Manual Traffic Surveys
Requested manual traffic surveys are carried out to understand traffic movements, types of traffic or pedestrian activity at specified sites.
- Video surveys – used on complex junctions or major roundabouts.
- Pedestrian surveys – Pedestrians are counted and timed crossing the road and compared to the volume of traffic.
- Registration surveys – using car registrations to measure volume and frequency.
- Delay studies and signal check surveys – measuring queue length and traffic volume.
From the analysis of information predictions can be made about traffic, and how changes or new developments may impact it.
Requested Temporary Automatic Counter surveys
Requested Temporary Automatic Counter surveys are conducted where 24-hour vehicle type or speed information is required at a specific location.
Radar-type counters are used mounted on sign posts or at the edge of the carriageway. The units are normally installed for a week to show traffic and speed patterns over that period and are particularly useful for monitoring issues of traffic movements overnight or early in the morning which would be missed by a manual survey, such as HGV movements.
These temporary automatic surveys also give a week long view of speed and traffic patterns which can be very helpful to assess any queries that may be raised in a particular area or about a specific route.