Expert: the so-called bar of iron does not meet basic scientific principles and technical standards
Recently, a known original inventions "bar of iron" (also known as the "straddling bus") occupy a lot of news focus. Alleged means to solve the urban traffic congestion, "inside the race car," which can carry more than more than 1000 passengers, caused widespread public discussion, setting off a boom.
Media reports, bar iron is a large-capacity width height tram, using a high efficiency and low carbon technologies, combining the advantages of BRT and subway as one of the new invention. Bar rail running above Road, consists of two layers, the upper passenger, lower traffic, greatly improves the efficiency of transport, to solve the urban traffic congestion.
However, the iron concept popular in Pakistan at the same time, the writer as urban transport practitioners who wish to think from the point of view of industry, talk about the bar iron innovations need to follow basic scientific principles.
First of all, need the correct value orientation of technology innovation. Starting point for bar iron is "as the way to the car." City transport resource limitation to the only priority, the resources allocated to the key aspects of the principal contradiction – public transport, to solve traffic problems. Concept of bar iron made is good and most of our limited road space to car traffic, rather than suppress car travel, are used to relieve traffic jams can hardly be made.
Second, the technological innovations required to meet basic scientific principles and technical standards. Bus many of the basic parameters of iron does not meet basic standards. Total height 4.5~4.7 meters of bar iron, lower car passage height of 2.2 meters, the upper passenger space height of 2.3~2.5 m. This size does not meet the minimum safety requirements. Car passage height 2.2 m satisfied with speeds below 5 km garage height requirements. Under the design speed of 50~60 km, 2.2 m headroom and no car driver was driving. In the design specification, even the non-motor vehicle road clearance height requires 3.5 meters, not to mention the vehicle? 5 and above a small passenger cars (vans) that is more wide of the mark. Second, space at iron upper design did not meet the basic needs of their customers. Pakistan railway length of 54 meters, 7.8 meters wide, the area of about 350 square metres of space for carrying passengers. Even so, taking into account the seating, the corridor space requirements, BA Fe host up to around 600-700, it is difficult to meet their "capacity of 1200-1400 passengers" in the first place. Third, this wide-body Super bus model is hard to meet the structural safety of vehicle stability requirements. Assuming Palestinian vehicles are only calculated at 600 people containing (but not inventor claims that 1000~1200 people), weight up to 35~37 tonnes, plus the weight of the body, it is estimated that close to 40 tons. BA rail trains, these 40-ton wide-body around its center of gravity height of 3 meters from the ground. Only supported by steel body shell is very thin on both sides, traveling at 30 kilometers above the speed under dynamic load impact, almost unable to guarantee the security and stability of the vehicle structure. Four is, Pakistan railway vehicles 4.5~4.7 metres high it is difficult to have both already existing overpasses and pedestrian overpasses and many dozens of even hundreds of roadside trees on city streets to promote the use of, or will lead to a lot of demolition, destruction of urban history, landscape and culture. In addition, the bar iron giant body does not meet the turning radius, crossing clearance and other regulatory requirements.
Of course, the public's aspirations and passions of innovation should be encouraged and protected. However, innovation needs to follow the most basic scientific principles, need to be fully demonstrated and rigorous scientific computing and not an event, and cannot be divorced from reality. At present, give priority to developing public transport, promote green travel is easing traffic congestion, the fundamental way to achieving sustainable urban transportation and way out.
(Author of Nanjing urban and traffic planning and Design Institute)
(Editors: Xu Zhiwen UN643)
2016-08-04 15:34:21
Integrated
专家：所谓巴铁不符合基本科学原理和技术标准
近日，一项被称为中国原创重大发明“巴铁”（又称“立体巴士”）占据了不少新闻的焦点。据称这种交通工具能够解决城市交通拥堵，“肚子里面能跑小汽车”，上面还能承载1000多名乘客，引起了公众的广泛讨论，掀起了一番热潮。
媒体报道，巴铁是一种大运量宽体高架电车，采用了高效低碳新技术，将BRT和地铁等优点融为一体的全新发明。巴铁运行时凌驾于道路之上，分上下两层，上层载客，下层可通车，大大提高了运输效率，从而有效解决城市交通拥堵。
然而，在巴铁概念火爆的同时，笔者作为城市交通从业人员希望从行业的角度进行一番思考，谈一谈巴铁创新发明需要遵循哪些基本科学原理。
首先，技术创新需要正确的价值取向。巴铁的出发点仍在于“为小汽车让路”。城市交通资源的有限性决定了只有分清主次、把资源分配给主要矛盾的主要方面——公共交通，才能有效解决城市交通问题。巴铁概念的提出，是把最有利又有限的路面空间让小汽车通行，而非从根本上抑制小汽车出行需求，也就很难作用于缓解交通拥堵。
其次，技术创新需要符合基本科学原理和技术标准。巴铁的许多基本参数还不满足基本的标准要求。巴铁总高度只有4.5~4.7米，下层小汽车通行高度2.2米，上层乘客空间高度2.3～2.5米。一是这个尺寸不符合最起码的交通安全要求。小汽车通行高度2.2米只满足速度5公里以下的车库高度要求。在50~60公里设计时速下，2.2米净空高度没有哪个小车司机敢开车行驶。国内外设计规范中，连非机动车道路的净空高度都要求3.5米，何况机动车呢？对5座及以上的小客车（面包车）那就更不靠谱了。二是巴铁上层空间的设计也不满足乘客基本空间的需要。巴铁长度达到54米，宽7.8米，可用于承载乘客的空间面积约为350平方米。即便如此，考虑到座位、走廊空间等要求，巴铁最多可承载600—700人左右，很难满足其“容纳1200-1400名乘客”的初衷。三是，这样的宽体超大客车车型很难满足车辆结构安全稳定要求。假定巴铁车辆仅按600人载员计算（而不是发明者宣称的1000～1200人），载员重量就高达35~37吨，加上车体自重，估计接近40吨。这40吨的宽体巴铁车厢其重心距离地面高度达3米左右。而仅靠两侧很薄的车体钢壳支撑，在30公里以上车速行驶中动载冲击下，几乎无法保证其车辆结构的安全稳定。四是，巴铁4.5～4.7米高度的车辆很难在既有已经存在立交桥、人行过街天桥以及有许多几十甚至上百年行道树的城市道路上推广使用，不然将导致大量拆迁，破坏城市历史、景观和文脉。此外，巴铁的巨型车体也不满足转弯半径、过街设施净空等规范要求。
当然，公众的发明创新愿望和激情应该鼓励和保护。但是，发明创新都需要遵循最基本的科学原理，需要充分论证和严密的科学计算，不能一蹴而就，更不能脱离实际。目前，优先发展公共交通、倡导绿色出行仍是缓解交通拥堵、实现城市交通可持续发展的根本途径和出路。
（作者系南京市城市与交通规划设计研究院院长）
(责任编辑：徐志文 UN643)
2016-08-04 15:34:21
综合