Table 1. Literature Review
The most common approach for collecting tolls was to have the driver stop and to pay for toll collector sitting in a tollbooth. However, it is now viewed as toll collection process, this is unfeasible principally due to its adverse impact on traffic flow and its high collection costs, not to mention its effects on the environment. Different problems associated with traditional toll collection methods urged sophistication in the approach. After progressive developments resulting mostly from flawed strategies,“Electronic” Toll Collection (ETC) systems proved to suitably deal with the shortcomings. Though many different ETC schemes are in operation across the globe, the fundamental is to be able to automate vehicle identification and assess the tolls requiring no action by the driver. This research was, therefore, focused on studying the varied approaches to electronic tolling while working towards a feasible solution. The approach adopted for implementing the prototype employed Radio Frequency Identification (RFID). The basic idea was to work with RFID chips affixed at a corner of the vehicle's windshield. As the vehicle would pass through the toll junction, the chip would be scanned by RFID readers calibrated to the same frequency as the chips, mounted on either end, and an ID, unique to each chip, would be sent to the server via an on-board WiFi module. This ID would be used as an index to look up the database, fetch the associated user's details, and assess the toll accordingly. The user would also be notified of the transaction via SMS and/or email. This would allow speedy passage of vehicles eliminating the heavy congestion. As an added benefit, this would also eliminate the need for traditional book keeping by permitting authorized personnel to access daily logs anywhere, anytime. This would mean centralized control, improved audit, vehicle tracking, and more. An online portal was also provisioned, allowing users to register themselves, to check their billing history, choose appropriate payment methods, to recharge their accounts or pay their dues.
Tolled highways are some of the busiest roads in the country, not only because of high volume of traffic, but also due to the fact that they employ a tedious and an inefficient practice of manual toll collection. Electronic toll collection system is used as a technology for fast and efficient collection of toll at the toll plazas. This is possible as the vehicles passing through the toll plaza do not stop to pay toll and the payment automatically takes place from the account of the driver (Al-Deek et al., 1997). The existing system works on the principle of dividing the toll way into a number of lanes, each serviced by a toll booth. Each toll booth houses two operators, one to collect toll payments as vehicles enter the toll plaza and the other to print and hand in acknowledgment receipts as vehicles move out. Towards the end of each lane, where vehicles exit the junction and join the free flowing traffic, stands another operator who drives the barricade mechanism to obstruct the passage of vehicles until the toll is paid.
The literature review represents a general idea (Table 1) of how ETC schemes have been implemented in different parts of the world. Also it shows the gaps which are solved by the proposed system.
Table 1. Literature Review
It has been opened in December 2003, the M6 Toll is a 27 mile long three lane motorway that runs to the north of Birmingham, broadly following the alignment of the existing A38/A5 through Staffordshire, in UK. The M6 Toll operates a closed tolling system with mixed tolling. Users pay for using the road on exit at one of the four junctions with toll stations, or at one of two mainline toll plaza stations. Sensors located along the toll lanes at these payment points undertake automatic vehicle classification in order to determine how many axles the vehicle has and height of vehicle from point of first axle. The toll levied depends on vehicle classification (Khali et al., 2006). Users must pay a 50 pence monthly lease fee for the tag, and, for an additional £2 monthly administration fee, tag users can receive a monthly statement of tag use by post and have to access their statement on the dedicated website. A minimum £30 balance on the tag is necessary for the account to be initiated (Athanassiou et al., 2005).
Tang and Van Ho (2007) filed a US patent on their proposed ETC system. Their proposed system provides two lanes: one on the side and the other where overheadbased antennas are installed per lane (Reddy et al., 2016). Both antennas are used for conducting toll transactions. Of the two, the side antenna will act as a backup in case the overhead antenna fails to capture the signal emitted from the vehicles. In case of a failure, the overhead antenna will be deactivated, and the side antenna will be activated. If the side antenna also fails, then an error signal will be issued.
It is evident that toll plazas are usually bottlenecks for traffic flow and the situation is bound to worsen. The usually sought alternative to deal with this is to build additional lanes. However, this option requires a huge investment and it does not even attempt to tackle the major issue – limited throughput of manual transactions. Under such circumstances, automating the entire process, independent of human intervention, seems a much more viable alternative. Toll road operators can create conditions that are conducive to improving the flow of traffic along the road and reducing journey times for the customer by eliminating the need for toll road, users to stop and pay at a tollbooth altogether. Such schemes are in operation across the world, with the majority operating in Europe and the United States. Building up on these, the study intends to propose a feasible scheme that can be put into effect of resulting in hassle-free operation.
One aspect that demands attention here is whether to employ a hybrid or a fully automated approach. The term 'fully automated' is a catchall to describe a system that does not involve manual payment, although not all users would be expected to opt into the system and provisions would have to be made for infrequent/occasional users. For such systems, the success rate would depend large extent on how vehicles that are not equipped and enrolled for electronic tolling are dealt with together with the onus of deploying mechanisms that accurately identify violations (Crabtree et al., 2008).
The current toll collection system requires each vehicle to stop at the toll junction and pay taxes, which results in long queues and heavy congestion all throughout the day. To avoid this, we need to automate the process so as to eliminate the delays involved. RFID tags for the expressway are available at the toll plaza through a prepaid account at private bank (Umbrajkar, 2015).
The idea is to use an RFID tag, say embedded in the license plates or affixed on a corner of the windshield, and as the vehicle passes through the toll junction, the tag is scanned by RFID readers mounted on either end and an ID, unique to each tag, is then sent to the server via an on board WiFi module. Appropriate amount as per the class of the vehicle will be deducted from the user's account (Umbrajkar, 2015).
This ID is used as a primary key to look up a database, also hosted on the server, to fetch the associated user's account details and open a secure transaction in order to deduct the toll amount. All this happens in “real-time”, as the vehicle passes through the toll junction. This, therefore, allows speedy passage of vehicles eliminating the heavy congestion. Thus, this research work proposes the replacement of the currently employed tedious system with a low-cost, as well as a low-power consuming system, which not only speeds up the entire process, but also aims to eliminate traditional book keeping and provision for daily traffic analysis.
The architecture of IoT based toll collection system was shown in Figure 1.
Figure 1. Block Diagram for IoT Based Toll Collection System
The purpose of this research are as follows,
The study does not address any regulations concerning the technologies or methodologies proposed and those governing the implementation of tolls in the country. The scope is bound to the implementation of a prototype that aims to readdress the impediments in the existing toll collection system.
Automated toll collection system is an adaptation which works in a similar manner to the traditional ETC except that it employs RFID for vehicle identification (Win & Myatnwe, 2014). The in-vehicle transponder consists of a passive RFID unit that operates in the 125 KHz Radio Frequency (RF) band using Dedicated Short-range Communication (DSRC) protocols. Stored in this RFID transponder is a unique identification number, which is used as an index to a database containing the user's details. The RCU emits radio frequencies in the same RF band as the transponder to communicate with it and use its identification number to assess the toll. The RCU emits radio frequencies in the 125 KHz RF band. As the transponder (vehicle) comes in the RCU's proximity, it draws power from the signals emitted and reflects its identification code back to the RCU. The RCU decodes this information and stores it in the buffer. The identification code is then fetched from the buffer and used as an index to look up a central database.
The associated user's details are retrieved and the toll is assessed accordingly. The user is immediately notified of the transaction via SMS and/or email. The system also determines whether the vehicles passing are enrolled in the program, and gathers information for further collection or enforcement. Suppose the transaction is successful, the barricade mechanism senses the presence of the vehicle and allows it to cross the junction. However, if the transaction fails due to insufficient balance or unregistered vehicle, the vehicle is directed towards a separate lane for manual collection of toll with a service penalty.
All the data is hosted on an Amazon Web Services (AWS) Relational Database Service (RDS) instance running MySQL. This database instance is linked to the web portal as well as ATCS (Automated Toll Collection System), thereby maintaining consistency and at the same time allowing concurrent access. Users are to register themselves for the ATCS program via the web portal. Once registered, the user's details are verified, the user is assigned a unique identifier and an in-vehicle RFID unit is shipped to the user's address. Hereupon, the user simply has to maintain sufficient balance in their accounts and zip through the toll plazas without having to stop to pay the toll. The web portal also provisions the users to easily recharge their accounts, check their billing histories, and add new vehicles. For the toll operators, the portal provisions centralized control, improved audits, daily logs, and vehicle tracking.
The system also makes use of two other services from AWS: Amazon Simple Notification Service (SNS) and Amazon Simple Email Service (SES). Rather than integrating a GSM module into the system and programming it separately or dealing with the mechanics of SMTP, Amazon SNS and SES were resorted to as simple yet effective means of notifying users of their transactions.
A Raspberry Pi will serve as the heart of the system, handling all communications with the cloud server. A web portal will also be designed allowing users to view a summary of their monthly toll deductions, a facility to recharge their RFID prepaid cards, and, for the users who have opted for the 'postpaid' billing method, a provision to pay their toll bills via credit/debit cards, net banking, and a variety of different means.
This portal would also allow administrators to view daily logs and interactive analysis reports, and address user grievances. The users would also be notified immediately, via SMS and/or E-mail, of the toll amount deducted as they cross the junction.
Figure 2 represents the online portal and together with simulations of the working prototype.
Figure 2. Web Portal Login
Figures 3 and 4 explain the details of vehicle theft detection. Vehicle location details will be given by entering the vehicle number.
Figure 3. Theft Detection
Figure 4. Vehicle Location Details
For the payment of toll, online recharge can be done by entering the vehicle number and user Id. Figures 5-7 describe the details of online recharge of the account.
Figure 5. Recharge RFID Tag
Figure 6. Payment Details
Figure 7. ATCS Prototype
Figure 8 shows the details of the transaction which is done from the user's account automatically when vehicle passes through the toll. The toll amount is deducted from the user's account and it shows the remaining balance amount.
Figure 8. ATCS Transaction Alerts
Electronic toll collection provides substantial advantages over manual toll collection, including reductions in transaction times, waiting times, fuel consumption, traffic congestion, air pollution, and operational costs. The greatest benefits from ETC are achieved with open-road tolling, which minimizes traffic impact as well as the footprint of the toll plazas. This also allows leveraging the existing facilities while implementing ETC.
Another point of concern is the vulnerability of the system to skimming and eavesdropping if the communication channel between the RFID tag and the reader is not sufficiently encrypted. A major decision point, however, is determining how to deal with vehicles that are not equipped or enrolled for ETC. It either prohibit such vehicles from using this facility or set up the hybrid system for cash payments.