The History of Traffic Counting

Since the invention of the wheel, the movement of people and goods has been an essential component of human civilization. As cities and communities grew, the need to manage and control traffic became increasingly important. One essential component of this process is traffic counting – the measurement of traffic volume and patterns to evaluate the effectiveness of transportation systems and plan future infrastructure development. This article will delve into the history of traffic counting, tracing back its beginnings, exploring different methodologies through time, and examining the state of the art today.

Early Beginnings

As early as ancient Rome, officials understood the importance of having accurate and up-to-date information on population and economic activities that could affect transportation demands. One of the earliest forms of a traffic count took place in 450 BC, with the Roman Census, which was used to determine the population, land distribution, and tax obligations of the citizens.

With the advent of the industrial revolution and the development of steam-powered locomotives in the 19th century, the need to monitor and control the movement of transportation vehicles intensified. It was during this time that various specialized tools and methods emerged to count the number of passing vehicles and people on roads and railways.

Manual Counts

One of the first methods used for traffic counting was manual counting of vehicles and pedestrians by human observers. In the late 19th and early 20th century, transportation engineers and researchers used manual counting procedures to collect and analyze data on traffic patterns. For example, the urban planner Charles Mulford Robinson used manual traffic counts to determine the effectiveness of traffic regulations in American cities during the early 1900s.

Manual traffic counting was conducted at intersections or other key locations, with individuals recording the number of vehicles that passed by over a specific period. This information could be used to help plan road infrastructure expansion or improvements, as well as understand the relationship between the layout of the city and the prevailing traffic patterns.

Mechanical Devices

As traffic volumes increased and more detailed data was required, manual counting became time-consuming and inefficient. In response, inventors developed mechanical devices to automate traffic counting. One of the earliest traffic counting devices was the trafficometer, patented by J.L. Schlatter and J.M. Morley in 1911. This device used a series of rotating disks that would turn each time a vehicle passed over a rubber tube stretched across a roadway. The device allowed for the collection of more detailed data, such as the total number of vehicles that passed over a selected time frame or the peak hour of traffic.

Electromagnetic Counters

Advancements in electronics and materials soon allowed for new traffic counting technologies to be developed. In 1948, Charles W. Bachman and Thomas F. Merrill, engineers at General Electric, invented the electromagnetic traffic counter, a device that used magnetic fields to sense passing metallic vehicles. This system offered greater accuracy and a more permanent installation, as the magnetic sensors were typically embedded in the roadway.

Video-Based Traffic Counting

With the increasing availability and affordability of video recording devices, video-based traffic counting and monitoring began to be popular in the latter part of the 20th century. This involves capturing video footage of a roadway and analyzing the video to determine vehicle volumes and other traffic metrics. Initially, video analysis was done manually, but it soon became automated with the development of specialized software and computer algorithms.

Advanced Technologies

Today, traffic counting employs a wide range of sophisticated technologies, including passive infrared sensors, inductive loops, ultrasonic detectors, and radar-based systems. However, the increasing importance of advanced traffic management systems, such as intelligent transportation systems (ITS), has spurred the adoption of integrated data collection technologies.

These integrated approaches take advantage of the wealth of real-time traffic data available from traffic signals, traffic cameras, cellphone data, and GPS information. By combining these data sources, transportation officials can make more informed decisions about road capacity, flow patterns, congestion and other traffic-related issues.

Conclusion

Over the history of traffic counting, our understanding of traffic behavior has improved substantially. The continuous evolution of technology has allowed for more accurate, efficient, and detailed counts that enable better planning and management of transportation networks. As cities and transportation systems grow ever more complex and interdependent, accurate and timely traffic counting data will remain an essential tool for effective transportation planning and management.