Autonomous Rail Rapid Transit
Autonomous Rail Rapid Transit (ART, ) is a LiDAR guided articulated bus system for urban passenger transport. Developed by CRRC Zhuzhou Institute Co Ltd, it was unveiled in Zhuzhou in Hunan province on 2 June 2017. The product has been described as a crossover between a bus and a tram and is commonly called a "trackless tram". Its external appearance, composed of individual, fixed sections joined by articulated gangways, resembles a rubber-tyred tram, although it combines the flexibility of a bi-articulated bus with the capacity of light rail or tram. Although the system is labelled  as "autonomous" in English, the models produced so far all feature a driving position with a steering wheel and the systems in operation all have a driver. Description. An ART bus with three carriages is approximately long and costs approximately 15 million yuan (US$2.2 million) to build. It can travel at a speed of and can carry up to 300 passengers. A five-carriage bus provides space for 500 passengers. A four carriage model was introduced in 2021 which can carry 320 passengers. Two buses can follow each other at close proximity without being mechanically connected similar to multiple  unit train control. The entire ART has a low-floor design from a space frame with bolted-on panels to support the weight of passengers. It is built as a bi-directional vehicle, with driver's cabs at either end allowing it to travel in either direction at full speed. The long ART lane was built through downtown Zhuzhou and inaugurated in 2018. It had lanes which are at least wide and has a minimum turning radius of . Both of which are comparable to or better than buses and light rail. Sensors and batteries. The ART is equipped with various  optical and other sensors to allow the vehicle to automatically follow a route defined by a virtual track of markings on the roadway. A steering wheel also allows the driver to manually guide the vehicle, including around detours. A "Lane Departure Warning System" helps to keep the vehicle in its lane and automatically warns, if it drifts away from the lane. A "Collision Warning System" supports the driver on keeping a safe distance with other vehicles on the road and if the proximity reduces below a given level, it alerts the driver by a warning sign. The "Route Change Authorization  is a navigation device, which analyzes the traffic conditions on the chosen route and can recommend a detour to avoid traffic congestion. The Electronic Rearview Mirrors" work with remotely adjustable cameras and provide a clearer view than conventional mirrors including an auto dimming device to reduce the glare. The ART is powered by lithium–titanate batteries and can travel a distance of per full charge. The batteries can be recharged via current collectors at stations. The recharging time for a trip is 30 seconds, and for a trip, 10 minutes. Benefits and limitations. A 2018 academic assessment said Trackless Trams  - like ART - are likely to replace both light-rail and bus rapid transit due to their ability to mimic the best qualities of each (low cost and ease of installation of BRT, low emission and high capacity of light-rail) while avoiding their respective defects (pollution and noise of BRT, high installation costs and disruption during construction of light-rail). Despite these apparent advantages, as of July 2021 there are only a limited number of planned systems. This may be as: -The system is not autonomous -The system is not rail based, hence has the ride qualities of a bus  -The vehicles can get stuck in road traffic, hence is not true rapid transit. -As a "gadgetbahn", the vehicles cannot be bought through true competitive tender. Having no permanent track enables flexible operations according to traffic conditions, e.g. by suggesting detours in the case of road traffic accidents or ongoing construction work. The vehicle based system interacts with an intelligent signal communication feature enabling priority pass at traffic lights. The railless system provides low construction and maintenance cost, because there are no railway tracks to maintain. Using quick charge batteries reduces the need for overhead lines en route between  the stations and produces no exhaust gases within urban areas. A significant advantage is the lower swept path in turns, thus requiring less clearance, due to the multi-axle hydraulic steering technology and bogie-like wheel arrangement. The minimum turning radius of is similar to buses. Since the ART is a guided bus system, ruts and depressions will be worn into the road by the accurate alignment of the large number of wheels. Reinforcement of the roadway to prevent problems and avoid future maintenance may be as disruptive as the installation of rails of a light rail system. The suitability  of the system for winter climate has been considered but not yet been proven on ice and snow. The higher rolling resistance of rubber requires more energy for propulsion than light rail. The ability to bypass other vehicles stopped at stations would allow express services, similar to some bus rapid transit systems. This is not possible with light-rail systems without significant extra infrastructure and is thus not used. The video for a proposed line in Sydney shows vehicles performing such an manoeuvre. A few abandoned proposals for light-rail lines have been revived as ART proposals because of its  lower projected costs. However a different report - by the Australian Railways Association which supports light rail - said there were reliability issues with ART installations, implying the initial suggested capital cost savings were a false economy. A November 2020 proposal for a trackless tram system in the City of Wyndham, near Melbourne, used a cost of $AU23.53M per kilometre for roadworks, vehicles, recharge point and depots. Recently completed light rail systems in Australia have had costs of between $AU80M and $AU150M per kilometre. The Government of New South Wales had considered the system as an  alternative to light rail for a line to connect Sydney Olympic Park to Parramatta. However concerns were raised that there was only one supplier for the technology and also the development of "long articulated buses" was "too much in its preliminary phase" to meet the project deadlines. Instead the plan is to build a light-rail line which will connect to another light-rail already under construction, which will mean passengers will not have to change vehicles. Despite this there are still proposals to use the technology elsewhere in Sydney and in a number of locations in Australia. The Auckland  Light Rail Group, in its studies of trackless trams for the City Centre to Mangere line, found that trackless trams would have a lower capacity than claimed. The official specifications for the ARRT assume a standing density of 8 passengers per square meter, whereas many Western transit systems have more typical standing densities of 4 passengers per square meter. Based on this the 32m long ARRT would more realistically have a capacity of 170 passengers, rather than the claimed 307. Proposed systems. Substantive proposals, including vehicle testing, have been made by relevant authorities for the following systems. Suggested applications  are not listed.