|For successful transport planning to take place, it is an essential requirement for transport planners to obtain a sound understanding of the actual conditions on the ground in order to predict what the conditions would be in the future. Often, the only way to achieve this is by obtaining an accurate measure of traffic numbers. This might be expanded to encapsulate vehicle types and speeds. If the objective requires more detailed data, then the journey length, the purpose of the journey and the frequency of the journey may also need to be determined.|
There are several types of traffic survey or counting methods used on traffic networks ranging from manual counting, road tubes and cameras to questionnaires and telephone surveys. Most transport planning consultants are familiar with all types of traffic surveys, but predominantly use camera technology. Unlike manually counted traffic surveys with staff counting on-site, a video survey can also be used for other purposes such as looking at driver or pedestrian behaviour, determining queue lengths or even identifying issues that may not be known.
Surveys are used for a wide variety of uses including helping to resolve national, regional and local traffic issues. In particular, the data gathered plays a major role in informing the decision making process in transport planning. This may include contributing to projects related to the planning, construction and maintenance of transport infrastructure. Importantly, with major investment apparently in short supply, traffic survey reports influence investment in future infrastructure as well as making the best of our current road networks. On a local level surveys are also utilised for smaller projects that may deal with parking issues or the effectiveness of traffic calming measures in regards to road safety issues.
On a minor project, surveys may only be required to determine vehicle 85th percentile speeds and two-way link (road) counts. This would help determine such issues as visibility splays and highway capacity and whether the development proposals would have an adverse affect on the highway.
Larger development schemes would require much larger studies which may require turning counts at a number of junctions, vehicle speed surveys, pedestrian desire line surveys, vehicle queue surveys and even observing how often pedestrians cross at a crossing and the affect that may have on vehicle flow. In certain situations, particularly where there may be some new road building (such as a bypass) origin and destination surveys may be required across the study area, which typically can be carried out using number plate surveys at all entry and exit points to the study area as well as within the study area at major intersections in order to track individual car movements.
Peter Jessop Price is a director at Modal Group Ltd and has worked successfully with clients as a transport planning consultant in the UK. As traffic consultants, Modal Group provides road safety audit services and traffic surveys as part of both residential and commercial development schemes. To find out more about traffic surveys, please visit the website at Traffic Surveys.