# Transportation Deployment Casebook/2018/Electronic Toll Collection System
## The simply description of Electronic Toll Collection system
### the technological characters

The Electronic Toll Collection (ETC) system is a kind of technology to toll in the HOV lanes and different highways but not require the car to stop. The special ETC road is only used for those drivers whose cars has vehicle mounted devices on them. The devices are also known as transponder facility. Generally, the driver need to create an account to load his money into his account and every time he passes by the ETC road, the sensors on the ETC road can detect the car with the transponder and charge by decreasing the saved money in the driver's account. The transponder facility which can create ratio waves is located on the car's windshield and the wave can be recognized by the sensors. The received wave can be transferred into the information on the internet and the amount of money will be deducted by the relevant website with the cooperation of banks.

### the advantages and the main market

The ETC system has many advantages comparing other tolling system. First, ETC special lane do not need the electric tolling booth, which means can avoid the noise made and the consumption of electricity when the gate opens and closes. Second, with ETC system, the government do not need people to take management of tolling, which can reduce the cost of human resource. Third, the most important point is the ETC system enable drivers to pay money by the vehicle mounted devices on the internet without stopping their cars. This improves the efficiency and reduces the waiting time when the clients are working and save the process of finding cash for tolling. As a result, ETC special way can be useful to tackle the congestion. So ETC system can avoid the traffic queue in congested roads. This technology is widely used in busy highways, toll roads, HOV lanes, tunnel and bridges environment to save people's time.

## the Scene Before the Advent of ETC system
### cash lanes

Before the electric tolling collection technology, government prefer the cash lanes to take charge. The government place some electric tolling booths with a gate to stop cars, where there is people working inside them. When drivers passing by the booths, he need to stop the car and find cash and give to the clients. After the confirmation of clients, the gate will be opened and drivers can get through it.

### open tolling lane

This lane is similar to the ETC special lane in some ways. This kind of tolling lane can also cashless toll. But the cars passing by must slow down to make sure the devices on the car be read, which may also lead to the congestion in some situations.

### the process of evolving

As the traffic capacity of the ETC special road is the four times of the traffic capacity of normal tolling lane. Besides, without the construction of the booths, the ETC lane can help save the traffic departments' investment, actually can save 40% construction fee. As for the operating cost, the cost for maintaining and management for ETC special lanes is much lower than that of normal lanes. So the government prefer the ETC system to save money. Drivers prefer this technology as well. With the widespread of ETC system, the drivers only need to sign up am account and save money inside it and don't need to worry about the cash problem when tolling and the congestion. ETC system is adopted by both drivers and government and gradually replaces the traditional tolling methods.

## The Invention of the ETC System
### component

The ETC system has two basic components: the RSU and OBU. The RSU is the road side units, like the sensors located in the ETC lanes. This unit is hung directly on the entrance of the ETC road, 5.5 meters over the ground. And the OBU is the on board unit, which is located on the inside windshield, like a vehicle-mounted devices and transponders which can send radio waves and be connected with the internet ( the account of the driver).

### the basic technology

The invention of the ETC system need many complicated technology. The three most important technology is:

### the technical facility
## The Market Development and the policy in birthing stage

The biggest problem faced is how to promote the ETC system. This system is the latest technology and it was not known and adopted by public. So how make make the ETC system popular and wide spread was a problem.

## The Growing Stage of ETC system
### America

In America, the most important ETC system is E-Zpass system. The system includes 23 electric tolling collection networks in total, but those networks accounts for 43% the average flow rate per month.

### Japan

In Japan, the government has applied ETC system to all highway all over the country. The elective tolling point is more than 2000 now and the ETC system user has been more than 40000000.

### China

Up to June 2011, there are more 22 provinces using ETC system with 1505 thousands users. And on 1/5/2013, the government decided to apply ETC system into all military cars. And according to the statistics in 2017, there are 28 province using ETC system and the number of the users who had account for ETC has reached 50000 thousand.

## Some Problem and Re-invent Part for ETC
### some problem

The privacy is one of the problem. As the road side unit and the sensors with ETC system can record the position of the cars. Many bad people may use the ETC system to get the position of specific people's position and predict his going， which his really dangerous and make a threat to the public privacy.

### solution and re-invent parts

So it is really significant to redesign the security part of the ETC system to avoid some information stolen. What is more, a system can be written that tolls without reading the information of the driver. With this system , the ETC system can be much safer.

## Quantitative Part

number of users with time :
| year | the number of users (10 thousand) |
| 2009 | 68 |
| 2012 | 510 |
| 2013 | 600 |
| 2014 | 1300 |
| 2015 | 2515 |
| 2016 | 3200 |
| 2017 | 5000 |
| | Passengers | S(t) = K/[1+exp(-b(t-t$_0$)] | | Y=LN(Passengers/(K-Passengers)) | Y=LN(Passengers/(K-Passengers)) | Y=LN(Passengers/(K-Passengers)) | k = | |
| Year | carried (thousands) | Predicted Passengers (thousands) | K | 7000 | 8000 | 9000 | 10000 | 10500 |
| 2009 | 68 | 71 | | -4.624395946 | -4.759152784 | -4.877887908 | -4.984009441 | -5.033125579 |
| 2012 | 510 | 437 | | -2.543607084 | -2.686913351 | -2.812233554 | -2.923583166 | -2.974929146 |
| 2013 | 600 | 781 | | -2.367123614 | -2.512305624 | -2.63905733 | -2.751535313 | -2.803360381 |
| 2014 | 1300 | 1357 | | -1.47810191 | -1.639743262 | -1.778856064 | -1.900958761 | -1.95683922 |
| 2015 | 2515 | 2254 | | -0.578465692 | -0.77974429 | -0.947219014 | -1.090628214 | -1.155291978 |
| 2016 | 3200 | 3504 | | -0.171850257 | -0.405465108 | -0.594707108 | -0.753771802 | -0.824723538 |
| 2017 | 5000 | 5000 | | 0.916290732 | 0.510825624 | 0.223143551 | 0 | -0.09531018 |
When k = 10000, the R square equals to 99.1372%, which is the highest. So we choose k= 10000 as the saturation status level, so we can also estimate b as 0.61722 ( using the equation Y = b X + c and Y = LN (number of users/(K-number of users))
as k = 10000, and t0 = 2017 ( for in 2017 , the user of the ETC is 5000)
in this way, we can draw the graph for S(t) = K/[1+exp(-b(t-t0)]

## Reference :

* ↑ https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1078&context=ktc_researchreports
* ↑ http://www.baike.com/wiki/ETC
* ↑ http://www.e-zpassiag.com/
* ↑ Balasch, Josep (October 2010). "Privacy-Preserving Road Charging". Katholieke Universiteit Leuven
* ↑ http://www.chyxx.com/industry/201706/532553.html
* ↑ http://t.cj.sina.com.cn/articles/view/6456330623/180d3c97f001004b3z