ITS and toll

By International Road Dynamic

Intelligent Transportation Systems (ITS) is perhaps not the first thing that springs to mind when you are searching for change as you pull up to a toll booth. But increasingly, toll systems are being examined as a solution not only for funding roads, but also for the enforcement of weight regulations and data collection purposes that are crucial to the operation of a modern transportation infrastructure system. The economies realized when one operation produces results can serve multiple purposes yields high returns from the efficient use of resources.

The Evolution of Toll Collection
The roadways, bridges, tunnels and interchanges that make up a country’s road transportation infrastructure are vital to the economic and social prosperity of that nation. The development and preservation of a safe and efficient highway system is therefore, an essential function of all organizations, both commercial and governmental, that are involved in transportation. Let’s examine how toll systems have evolved to become a significant part of the ITS picture.

Tolls and Revenue Generation
The first and most traditional role of tolls is as a method of collecting funds to pay for a section of road. This function is almost as old as road building itself; as soon as roads became something more permanent than a trail, there had to be a way of paying for them and collecting a fare from the users was simple to implement and seen as fair by the users.
Things didn’t change a lot for the next few millennia. The development of the automobile brought the need for more and better roads, but the collection method was essentially the same: a person at a toll gate collected money from the user traveling on a section of roadway. But as the vehicle density increased on highways in the 1950s, this manual process became a major bottleneck impeding the flow of traffic. The solution was automatic coin collectors. Based on mechanical coin sorters used in banks, these speeded up the collection process and reduced congestion to a manageable level.

The next step ahead was to eliminate the need for cash (or the equivalent tokens) by providing some form of Electronic Toll Collection (ETC). In its simplest form, the mechanical coin collector was merely replaced by an electronic scanner capable of reading a prepaid fare medium such as bar coded tickets, a magnetic stripe card, or a Smart Card; the system still relied on a human to match the fare to the vehicle. The advantages were twofold: for the user, it provided the convenience of not having to carry around cash or tokens; the seller gained the benefits of electronic accounting and was freed from the inconvenience of handling large sums of small denomination funds.

A parallel development occurring at approximately the same time as ETC was automatic vehicle classification. This was made possible with the addition of a variety of sensors such as inductive loops for sensing vehicle presence, piezo-electric and piezo-resistive sensors for detecting axles, infrared detectors to sense vehicle dimensions and imaging systems to provide pictures. Fares based on vehicle class could now be automatically selected by the system as vehicles entered the toll lanes.

When ETC was combined with automatic vehicle classification, the toll collection system became completely automated. The development of Dedicated Short Range Communications (DSRC) radio transponders for ETC allowed both the vehicles identification and the fare transaction to be carried out without the vehicle stopping. At first this just meant better throughput at typical multi lane toll plaza, but it was soon also incorporated into toll systems that could perform the toll transaction transparent to the user as their vehicle entered or exited the road system at normal highway speed. Advanced ETC such as DSRC tags has also allowed toll collection agencies a variety of options: toll tags can either be sold with a prepaid sum on account and the fare deducted on each use or toll tag can be tracked for a period of time and an invoice issued for the amount of use during the billing period. Compliance checks and identification of users without DSRC tags was performed using License Plate Reader (LPR) video imaging sub-systems.

The most recent developments have involved using satellite transponders to track and identify vehicles anywhere on a national road system. This system allows invoiced tolling based on the exact roads used and distance traveled. In essence, every road becomes a toll road. The system does require nearly 100 % of the users to have a satellite transceiver, so mandatory registration, (similar to the current license plate system) is obligatory. As the main requirement for variable toll rates applies to heavy vehicles, the system, at least initially, has been used only with commercial vehicles. 

Tolls and Data Collection
With the advent of ECT, automatic vehicle classification and the computerized accounting that accompanied it, data collection became an immediate by product of the system. The only hurdle to this application was developing a pathway for accessing the data between the organization performing the toll collection and the one who could use the data for infrastructure policy and planning purposes.

Tolls and Enforcement
It was established fairly early in the research into wear and tear on roadway infrastructure that the deterioration caused by any given vehicle is directly proportional to the weight of each axle of that vehicle. In fact the rate of wear was found to increase approximately as a fourth power exponential function of weight; i.e. a doubling in weight increases wear by a factor of 16.
Two consequences are immediately apparent from this fact:
1. It is essential that highway infrastructure be protected from overloading of vehicles.
2. A fair and equitable method of “user pay” in term of the cost of consumption of highway infrastructure must be based on axle weights.

The traditional method for enforcement of weight regulations has been inspection stations with static weigh scales located adjacent to major highways. These have the drawbacks of being expensive to build and operate, easily avoidable by violators and, as truck traffic has increased, unable to cope with the volume of commercial vehicles using the highway. The piece of the ITS puzzle that provided a solution to these problems was Weigh-In-Motion (WIM). WIM is relatively economical, unobtrusive and allows every vehicle to be weighed and classified at highway speeds with no disruption to traffic flow.

When integrated with an ETC using a communications link (either DSRC or satellite) WIM provides a seamless system for vehicle identification, toll collection, data collection and enforcement of regulations all in one package.

An Example History in Toll System Development
Let’s take a look at a real life toll system development history that roughly follows the process described above. International Road Dynamics (IRD) is an ITS company whose roots go back to the early days of the theory and implementation of first practical Weigh-In-Motion systems in the mid 1970s. From this it has grown into the supplier with the most installed WIM systems in the world. So how did it find itself in the toll business?

In the early 1990s, IRD had developed the Dynax Treadle, an axle sensor used in vehicle classification with a very high accuracy rate, good reliability and that was able to operate independent of vehicle speed. They had also the Single-Dual s tire width sensor. Both types of sensor were used in IRD’s WIM systems. These products were selected for use as sensors in toll lanes by contractors installing toll systems.  This soon led to requests to act as a sub-contractor to supply and install sensors on toll systems in the United States.

In the mid 1990s IRD became the primary supplier for a toll system in South America and developed a software system to perform automatic vehicle classification for a toll plaza environment using the inputs from its sensors. Soon after this, IRD began supplying toll systems in Asia.

In response to the need for a sophisticated software package for managing a toll system, IRD developed the iToll (integrated Toll) system in 2002. iToll was capable of performing the control functions, record keeping and administration operations needed to operate a toll plaza. Video image recording was added in 2004 as a way to aid vehicle identification. iToll incorporated early forms of ETC using bar code and Smart Card transactions in 2003. In 2006 DSRC tags were included in the ETC options, allowing flow through toll plazas.

 
Toll Plaza India
In 2007 WIM@Toll was introduced, integrating WIM technology into the sensor package. IRD manufactures a number of types of WIM scales, including single load cell, bending plate and slow speed scales, offering the customer a variety of WIM options to meet the particular requirements of their toll system. With the inclusion of WIM and DSRC, IRD now had a system that could automatically collect tolls based on weight, perform data collection and carry out enforcement of overweight regulations. 

To date IRD has installed over 8600 WIM lanes and 2900 toll lanes worldwide, including 1360 lanes of WIM@Toll.

So with a fully integrated ITS toll system, agencies in charge of road transportation infrastructure have a tool that will:
1. Collect the traffic data needed to plan future infrastructure policy
2. Enforce weight regulations that are vital to the preservation of the infrastructure
3. Collect the funds necessary to pay for the building and maintenance of the infrastructure

That’s a lot of mileage from one process.

Contact details:
Joe Clavelle, VP International Business
T: +1 (306) 653-6600, E: joe.clavelle@irdinc.com, W: www.irdinc.com