2. 外语
  3. Intelligent Transport System Today, there are many ways to travel around a large metropolitan area, for work or pleasure. Yo

Intelligent Transport System Today, there are many ways to travel around a large metropolitan area, for work or pleasure. Yo

admin2010-08-21  29
问题                                  Intelligent Transport System
    Today, there are many ways to travel around a large metropolitan area, for work or pleasure. You could walk, although the range is admittedly low. You could bicycle, but you still do a lot of work, and it’s dangerous. You could drive a car, which takes concentration and sobriety and a license. You could ride a bus, and let someone else drive. You could take a train, and let a computer drive you. Or you could fly, and wait a long time for the plane to take off and land.
    All modes of transportation have advantages, and disadvantages. However, in recent decades, the single system that has won over all others is the private automobile. This allows you to go from your starting point to your destination point, with your complete control, at a reasonable speed in a reasonable time. Unfortunately, apart from the pollutants created by the vehicle itself, the fact that so many other people seem to enjoy its perceived freedom causes major traffic jams, and the requirement for traffic control devices.
    Too many people using too little road space at the same time causes traffic jams. It is most profound on large grade separated roads, that have limited access. There have been various solutions tried out, including high occupancy vehicle lanes, ramp metering, or road widening. Unfortunately, they simply don’t solve the problem of lack of capacity.
    Traffic control devices impose certain controls on the flow of traffic. Most common are traffic lights. These meter the flow of traffic between two or more roads so that at no time is any vehicle in conflict with any other. However, they also impose that traffic comes to a complete stop, requiring vehicles to stop and then start again. This not only slows vehicles down, but also is the prime cause of wasted energy in urban settings.
    Unfortunately, cities are very reluctant to spend money. Therefore any future transport system has to be cheap for cities. This implies that current infrastructure is kept as much as possible, or improved. Using roads, the prime infrastructure available today would mean the form factor for vehicles would stay the same, but each individual vehicle could be made more intelligent.
    So for tomorrow, we need to design a transport system that uses roads or a very slight improvement on roads to provide a high capacity system that provides service for everyone. This could be achieved by implementing the following eight systems, each of which provides more of a burden on the car manufacturer, but would eventually provide a system, which is automatic, safe and efficient.
    Firstly, all cars should have intelligence brakes and cruise control. These would remove the driver from the responsibility of having to follow along behind somebody. By pressing a button, the driver would give control of the distance between his car and the car in front. If the car in front slowed down, you would not have to wait for the brake lights to light up, the driver to see them, Wen press the brake pedal the right amount, and continuously monitor the distance. Instead the car would be programmed to continuously monitor the distance to the car in front and instantly alter its speed to match and maintain the distance.
    By speeding up the feedback circuit, you can close the distance of cars, and therefore increase the capacity. You also remove driver error so reducing the number of accidents. Also, cars could communicate locally with each other and ware ahead of time that following cars need to slow down.
    Next, you need to remove the driver from the responsibility of steering the vehicle. Having complex vision systems on a car seems over the top as they not only dramatically increase the cost of the car, but also the complexity of the control software. Instead you could build detector into the front of the car that detect the middle of a lane of traffic. The car would try and keep the vehicle in that lane. Junctions could be built by having the centerline split. The operator or route planning software would decide which of the two or more signals to follow.
    Separating lanes of automatic cars from those driven by humans especially on high speed highways, would give an incentive to not only purchase an automatic car but also to purchase the road space which it uses. Since these separate lanes would have not only fast moving traffic but also safer traffic, they could be marked and sold by cities to create a revenue stream to allow the building of more augmented roads.
    Having a device in the car that does route planning is a great help for people who don’t know the way around your city. But what if you lived in the city for many years? It’s not going to be that much use, is it? By linking route planning with real time information on traffic levels in the city, you can quickly divert your journey to use the most efficient roads. This information could be relayed to vehicles using broadcast radio. Roadside sensors that determine the flow of traffic on a road would detect the speeds.
    The ability to remove the parking requirements from near a building would allow more compact cities, which are better pedestrian environments. However, people don’t like to walk from a parking structure that is a long way from their destination. The solution is to allow the car to drop off the passengers where required and then drive itself to the nearest parking structure that is known to have a space.
    By automatically controlling the speed and location of all traffic, you can’ make junctions work very efficiently. At the moment, some traffic has to stop, and when it resumes, the cars spread out into a large disperse volume. Instead you could move each group of cars as a packet, adjusting its speed so that it arrives at an intersection at just the right time so that it never has to stop. This could be achieved by changing the speed of a section of road so those cars slow down gradually. The speeds of road segments would be set by nearby junction computers each linked to the other. This would create a holistic traffic control system. If one section lost power, the system would revert to a normal junction.
    When a group of people move from one location to another, it would make sense to allow them to travel together instead of having to each use a separate vehicle. On demand group transport would allow the request of a large vehicle which can automatically move people from one location to another. These vehicles would be stored at strategic locations, and then sent to the requesting site as quickly as possible. Vehicles could be booked in advance, and you pay by the time used in minutes, not the distance traveled or destination.
    At the other end is the replacement of the taxi. This would be similar to the group transport but for smaller groups. Again these vehicles would be stored at strategic locations, so that people don’t have to wait very long. Again they are hired by the minute of use. Since you are no longer required to own your own vehicle, the total number of vehicles required in the whole system is reduced, and therefore the number of parking spaces required. Given a fully demand driven transport system, you would never need to find another parking space in your life.
    After the above is implemented, you have on demand private or group transport vehicles driving themselves from point to point without the need to stop at junctions, wait for traffic jams on freeways, or get lost along the way.
Traffic lights are the most common traffic control devices.
选项 A、Y
B、N
C、NG
答案A
解析 文章第四段中提到交通指示灯是最常见的交通控制装置。
转载请注明原文地址:https://kaotiyun.com/show/gsz7777K
0

大学英语六级

相关试题推荐
随机试题
最新回复(0)