Traffic surveys –Traffic information as an aid to decision-making and planning
Reliable traffic information is a key factor in the planning of land use concerning the road and street network, the making of plans, and decision-making. Correct forecasting is necessary for the economically sensible timing of different measures. Planning traffic environments and developing their functionality and safety call for analysed information on traffic volumes and traffic flows.
The assessment of the profitability of road and street construction projects needs reliable information about the present traffic volumes and, on that basis, predicted future traffic volumes.
The maintenance of a level of service for road/street traffic requires information about problem locations for traffic, so that measures to improve safety, driving comfort and traffic throughput can be allocated in the right way. Restoration of the road network, such as structural maintenance and daily care, can be performed more purposefully and economically if information about traffic volumes at different times is properly utilised.
We carry out traffic surveys nationally using our diverse and modern range of counting equipment. We are also developing survey methods on a customer-specific basis. As a result of all our traffic surveys and measurements, we get high-quality and clear tables and graphic presentations.
Destia’s range of services includes a comprehensive selection of traffic survey- and traffic information-based services:
- automatic traffic counts
- intersection counts
- speed measurements/surveys
- mobile speed displays
- noise level measurements/surveys
- pedestrian and bicycle counts
- axle weight analyses
- destination surveys
’Roadside technology’ means technology on or by the road, which measures and conveys different information about vehicles and driving conditions. Roadside technology includes automatic traffic measuring points (a.k.a. LAM points), changing signs, driving condition cameras and weather stations.
In general, local Centres for Economic Development, Transport and the Environment own the roadside technology equipment, but Destia carries out its maintenance. Destia’s Road Data Collection and Analysis unit is responsible for about 70% of the fault repair and annual maintenance of LAM points nationally.
Destia has at its disposal cameras suitable for identifying car number plates, which can automatically photograph and collect the number plates of passing cars. By means of these number plates, it is possible to find information about the cars and their owners in Trafi’s database, using Destia’s partners. This information can be used, for example, for carrying out different traffic surveys.
Destia produces different information services, for example from public road register information or based on measured data, as well as customer-tailored services in order to survey the condition of and volumes of traffic on the road network.
Destia’s range of services also includes different traffic reports. The reports can be based on general traffic counts carried out on roads, the results of fixed LAM points (a.k.a. automatic traffic measuring stations) or based on sampling counts performed. The reports may cover, for example, the whole country, the area of a certain Centre for Economic Development, Transport and the Environment, or the area of a province or municipality.
Traffic volume data is usually needed for planning and monitoring measures. Destia’s product range includes different traffic volume surveys, such as:
- Vehicle counts
- Pedestrian and bicycle counts
- The establishment and maintenance of fixed automatic traffic measuring points (LAM)
- The establishment of fixed radar counting points, and the supply and management of results
- Parking area surveys
Usually traffic is counted automatically during a pre-agreed sampling period, usually one week long. If necessary, vehicle counts can be classified into different vehicle classes. Depending on counting technology, such classification takes place based on, for example, vehicle length or number of axles and wheelbase information.
The calculations are normally reported in tabular and graphic form on an hourly basis by vehicle class. Traffic volume data for vehicle traffic can also, if necessary, be presented by general traffic codes (such as KVL, KAVL, KKVL, KVLras, KAVLras, KVLyhd, KAVLyhd). If necessary, the results can also be reported more broadly and it is also possible to add vehicle speed and other information. However, if the speed information is the primary object of interest, we recommend a speed report rather than a traffic volume report.
For the purposes of performing the counting, Destia has at its disposal a range of traffic counting equipment, from which we choose the most suitable device and technology for the need in question.
Destia can plan and implement the making of different traffic volume maps based on customer need. Traffic volume maps can be based on general traffic counts carried out on roads or on traffic volumes from fixed LAM points (a.k.a. automatic traffic measuring stations). The maps may cover, for example, the whole country, the area of a certain Centre for Economic Development, Transport and the Environment, or the area of a province or municipality.
Traffic flow data at intersections can be surveyed by means of junction calculation. This means that the direction of approach and departure of vehicles at the junction is surveyed by vehicle class. If necessary, we can also calculate the volume of non-motorised traffic (cyclists and pedestrians) passing through the area of the junction. Junction counts can be carried out either using the traditional manual method or by automatic video counting. Usually, counting is done during peak hours in the morning and evening. The most common time for counting is 6:00–10:00am and 2:00–6:00pm. The results are usually reported at 15-minute intervals allowing the hour of peak traffic to be identified (such as 7:15–8:15am) and the exact traffic volume established.
In addition to actual junction counts, we can also carry out efficiency checks at different intersections. In efficiency checks at intersections, we use the Synchro/SimTraffic software. With Synchro, we can analyse how well light-controlled intersections, non-light-controlled intersections, roundabouts and multi-level interchanges are working. Synchro provides estimates of the load factor and service level of the intersection, classified by turning direction.
Synchro’s throughput model is based on the Highway Capacity Manual (HCM). SimTraffic is a micro-simulation program connected to Synchro that can simulate traffic behaviour in an actual situation. For source data, traffic flow information at the intersections is needed, as well as geometric information about the road network and information concerning traffic control at the intersections.
Through such simulation, we can compare the efficiency of different intersection arrangements at different levels of demand. By simulation, we can also study the effects of intersection arrangements on the local area, such as the impact of a neighbouring light-controlled intersection on the efficiency of a non-light-controlled intersection. Simulation software can also be used to assess the impact of different types of disturbances such as a lane closure. The key parameters provided by simulation that can indicate the efficiency of an intersection are delays, lengths of queues, journey times, average speeds and fuel consumption. A simulation program can also use animation to illustrate how intersections function.
Destia carries out vehicle speed measurements on the road and street network. Vehicle speed information can be measured by radar counter without drivers noticing, whereby the received speed data is sent only to the organisation that commissioned the survey. Alternatively, a speed display board can be connected to the measuring device, allowing the drivers of the vehicles to see their speed too. The method of measuring speed information mentioned first can be used if, for example, you want to study the need to reduce driving speeds. It is also suitable for so-called ‘before and after’ surveys, which can examine the effect on driving speeds of the construction of speed bumps, among other things.
A temporary speed display board is a direct way of reducing driving speeds locally. Its effectiveness can be increased by using smiley faces, whereby the driver gets immediate feedback about either speeding or driving within the speed limit.
The applications for a speed display board include:
- road, street and building site areas, which need to display speed temporarily and where there is a desire to reduce driving speeds
- at places where the safety of other parties must be particularly taken into account, such as road sections where there is a school, old people’s home, service flats, a day care centre or a nursing institution
- as a source of additional information for motorists who can monitor/check the speed of their vehicle at a certain point
- at places where there is a desire for motorists to pay particular attention to their driving speed
In addition to a display board, the following information can be collected about the location:
- total number of vehicles by class (light/heavy)
- vehicle-specific speed information before the board and at it
- analyses of vehicle speeds and traffic volumes at specific points
A speed display board can be attached either to existing infrastructure by the road or street (lamp post, traffic signs, etc.) or to its own base.
In addition to speed information, we also supply a diverse range of reports and graphic charts about other calculations.
The purpose of destination surveys is to collect information on from where and to where journeys are being made. Destination surveys are carried out in connection with regional traffic surveys and, for example, for the needs of traffic system planning.
They are also done for specific projects, for example in connection with harbour projects. The surveys are usually done by means of roadside interviews or roadside postal questionnaires.
Destination surveys can shed light on the following types of traffic information:
- point of departure and destination (municipality and type of location, may also be an address)
- journey time and length of journey
- type of vehicle
- number of passengers
- purpose of journey
Destination surveys are carried out as sampling surveys. In order to extend the sampling, a traffic count is done daily at the same time as the interviews. In order to extend the traffic volumes to KVL level, day and period extension coefficients based on LAM points are used.
Axle weight analyses
Vehicle configuration was changed on 1 October 2013, as a result of which the maximum permitted total weights for heavy articulated vehicles increased. Heavier vehicles than before are now increasingly stressing both the road structure and bridges. The total load caused by vehicles can be studied by means of axle weight surveys in which the axle weight of heavy goods vehicles is measured. The results can be extended to all traffic based on traffic volume data.
The measurements from an axle weight survey can be performed on dynamic drive-over scales, whereby the vehicle does not need to stop on the scales when it is being weighed. In the survey, the suspension and tyre type on each axle are also usually established. At the same time, information about vehicle loads and points of departure and destination can be looked into (c.p. destination survey). Usually a destination survey cannot be carried out amidst traffic but requires a separate survey point for measurements and a possible interview.