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Article On BRT Spread around the World: Analysis of Some Particular

Salvatore Trubia 1 , Alessandro Severino 2,*, Salvatore Curto 1, Fabio Arena 1 and Giovanni Pau 1

1 Faculty of Engineering and Architecture, Kore University of Enna, 94100 Enna, Italy; [email protected] (S.T.); [email protected] (S.C.); [email protected] (F.A.); [email protected] (G.P.) 2 Department of and Architecture, University of Catania, 95123 Catania, Italy * Correspondence: [email protected]

 Received: 31 August 2020; Accepted: 22 September 2020; Published: 20 October 2020 

Abstract: The goal of civil engineering has always been the research and implementation of methods, technologies, and infrastructures to improve the community’s quality of life. One of the branches of civil engineering that has the strongest effect on progress is . The quality of transport has a profound economic and social impact on our communities regarding trade (freight transport) and livability ( systems). However, is not the only way to improve the features above-mentioned, especially public transport, considering that it is usually beneficial to enhance and repurpose vehicles with appropriate adjustments to offer more efficient services. Other perspectives that influence public transport systems are the costs and times of design and construction, maintenance, operating costs, and environmental impact, especially concerning CO2 emissions. Considering these issues, among the various types of existing public transport systems, those of the so-called (BRT) offer worthwhile results. The BRT system is a type of public transport operated by bus on reserved lanes, and it is significantly profitable, especially from an economic point of view, in areas where there are existing bus routes. Nonetheless, for the construction of works minimization, it is closely linked to other features that improve its usefulness, depending on the vehicles’ quality such as capacity, but above all, the propulsion or driving autonomy that would guarantee high efficiency. This paper introduces an analysis of some BRT systems operating worldwide, presenting the background, general technical features, and the correlation with autonomous vehicles.

Keywords: BRT; mass transit; autonomous vehicles; public transport; smart city

1. Introduction The implementation of a public transport system in a city is not a usual event. This is why, before construction begins, every component and feature has to be designed to ensure its efficiency for long periods. For these reasons, both for existing mass transit systems and new ones, the perspective of maintenance and retraining appears fundamental. It is worth considering that with existing and a few adjustments, like what Bus (BRT) requires, an efficient service would be guaranteed, and offers a convenient solution for city administrations. The BRT public transport system was introduced in 1974 in (). The reasons that led the administrators and technicians to make this choice were economic—reduced funds to construct a rail system—and social—because of the population increase in the city—requiring a public transport system with high capacity vehicles. After Curitiba, BRT spread worldwide, especially in Bogotà, with the implementation of “TransMilenio” in the 1990s. Such a system still represents a model for all public transport arrangements, and mostly

Infrastructures 2020, 5, 88; doi:10.3390/infrastructures5100088 www.mdpi.com/journal/infrastructures Infrastructures 2020, 5, 88 2 of 13 it also showed how BRT is efficient for complex urban layouts. Before 1990, BRT operated only in eighteen cities, while, nowadays, it is active in 173 cities and serves 34,026,459 daily [1] (Table1).

Table 1. Global (BRT) data.

Regions Passengers per Day Number of Cities Length (km) 491,578 (1.44%) 5 (2.89%) 131 (2.52%) 9,471,593 (27.83%) 44 (25.43%) 1625 (31.26%) Europe 1,613,580 (4.74%) 44 (25.43%) 875 (16.84%) 21,032,465 (61.81%) 55 (31.79%) 1829 (35.19%) Northern America 981,043 (2.88%) 20 (11.56%) 627 (12.06%) 436,200 (1.28%) 5 (2.89%) 109 (2.09%)

The benefits of a typical BRT system consist of dedicated lanes and proper vehicles and stations. Such a layout guarantees a significant advantage in terms of intermodality and interoperability. If such features are accessible to other specific vehicles, like emergency ones, then, due to reserved lanes, the congestion phenomena could be avoided for the public transport system and ordinary traffic, for instance, when users attracted by the efficiency of BRT give up using their private vehicles. Commonly BRT is considered an upgrade of existing bus mass transit systems that emulate rail systems but with reduced costs and construction times. For example, the construction costs for a single kilometer of BRT are only 52% of the costs of a system and 8% of those of massive rail system construction [2]. A strategy that is commonly used to appeal to citizens consists in stations or creating reserved lanes in places where there are parking areas for private vehicles. In this way, private vehicle users are more likely to find themselves caught up in congestion and less likely to find a parking place, thereby encouraging people to prefer the use of public transport systems. Some comparative data between BRT systems and more traditional transport systems are shown in Table2.

Table 2. Comparison of the public transport systems parameters.

Capital Costs Type of Transit Mode Capacity (pphpd) Operating Speed (km/h) (Million US$/km) Standard bus - 3180–6373 10–30 BRT Up to 15 Up to 55,710 18–40+ LRT 13–40 Up to 30,760 18–40 Heavy rail system 40–350 52,500–89,950 20–60

Generally, when a new mass transit system has been implemented, the area where it is located must be subjected to requalification works, producing a relevant cost increase. Such a case appears conveniently when the local administration decides to create so-called transit-oriented development (TOD) areas to maximize public transport use. These places are characterized by people living near transit hubs, so there would be the need to invest in activities close to these areas [3], making an essential requalification with significant consequences in terms of property value increase. The main aim of this paper was to review some of the BRT systems operating worldwide. The following subsections will present the background, general technical features, and the correlation with autonomous vehicles. This last section represents a viable distinguishing trait of the review carried out in this paper. The discussion examines the perspectives concerning autonomous vehicles and how they can enhance and influence mass transit and, mainly, BRT systems, in a positive way, creating meaningful profits for communities. Infrastructures 2020, 5, 88 3 of 13 Infrastructures 2020, 5, x FOR PEER REVIEW 3 of 13 2. General Technical Aspects 2. General Technical Aspects To achieve the high efficiency of a BRT system, regardless of new construction or existing mass To achieve the high efficiency of a BRT system, regardless of new construction or existing mass transit upgrades, several aspects must be taken into account to minimize future interventions. As transit upgrades, several aspects must be taken into account to minimize future interventions. As for for any other infrastructure, the design phase represents the central part of the implementation of any other infrastructure, the design phase represents the central part of the implementation of a a public transport system. This is why, before drawing the physical elements of a BRT system, it is public transport system. This is why, before drawing the physical elements of a BRT system, it is necessary to carry out in-depth studies about city urban assets, a demand analysis of potential users, necessary to carry out in-depth studies about city urban assets, a demand analysis of potential users, the identification of critical points, analysis of existing mass transit systems, and corridor selection [4,5]. the identification of critical points, analysis of existing mass transit systems, and corridor selection Once the design phase has been concluded, it is possible to begin building and installing the following [4,5]. Once the design phase has been concluded, it is possible to begin building and installing the main elements that characterize a BRT system: following main elements that characterize a BRT system: Running lanes; • Running lanes; • Vehicles; • Vehicles; • Stations; • Stations; • ITS, information, and control systems. • ITS, passenger information, and control systems. Running lanes represent the mainmain characteristiccharacteristic ofof BRTBRT systems,systems, forfor economiceconomic reasons.reasons. Their construction generally amounts to 50% of infrastruc infrastructureture costs; concerning their asset and dimensions that stronglystrongly aaffectffectthe the e efficiencyfficiency of of the the BRT BRT service, service, usually usually the the standard standard width width of aof BRT a BRT runway runway is 3.5 is m,3.5 asm, shown as shown in Figure in Figure1. However, 1. However, this width this is width reduced is reduced to 3 m to to guarantee 3 m to guarantee a lower speed, a lower decreasing speed, accidentdecreasing risks accident for safety risks reasons. for safety Regarding reasons. theRegard lane’sing position the lane’s ina position road section, in a road it is preferablesection, it tois locatepreferable them to at locate the edges. them at In the this edges. way, passengersIn this way, do passengers not need do to crossnot need the to street cross to the reach street the to station. reach Thisthe station. is why lanesThis is are why often lanes located are often in the located middle in of the the middle road section of the only road when section that only part when of the that itinerary part isof withoutthe itinerary stops. is The without construction stops. The of barriers construction at the edges of barriers of the at lanes the isedges a solution of the that lanes guarantees is a solution only publicthat guarantees service vehicles. only public However, service the vehicles. absence Howeve of barriersr, the proves absence useful of barriers when, inproves the case useful of accidentswhen, in orthe dangerous case of accidents situations, or otherdangerous vehicles situations, need a recovery other vehicles place, or need to facilitate a recovery access place, to ambulances or to facilitate that needaccess to to avoid ambulances congested that areas. need Nevertheless, to avoid congested in that case,areas. the Nevertheless, lane must maintain in that acase, correct the widthlane must that allowsmaintain the a presencecorrect width of more that than allows one th vehicle.e presence of more than one vehicle.

Figure 1.1. General Bus Rapid Transit (BRT)(BRT) corridorcorridor section,section, u.m.u.m. == meters.

For these reasons, running lane dimensionsdimensions are strongly aaffectedffected by vehiclevehicle characteristicscharacteristics that mainly depend on two parameters: size and propulsion. The first first is related to driver labor costs per passenger, user comfort,comfort, service capacity, andand frequency.frequency. InIn contrast,contrast, thethe secondsecond hashas consequencesconsequences concerning emissionsemissions and and environmental environmental impact. impact. In In lower-demand lower-demand corridors, corridors, it is suggestedit is suggested thatlarge that buseslarge buses are avoided are avoided to reduce to reduce waiting waiting times times for users. for users. It has It has been been noted noted that that typical typical BRT BRT effi efficiencyciency is attributedis attributed to vehicles, to vehicles, but the but operation the operation quality is quality significantly is significantly affected by stations.affected Suchby stations. infrastructures Such mayinfrastructures be configurated may be in configurated several diff erentin several ways different according ways to theiraccording role. to Generally, their role. it Generally, is possible it tois distinguishpossible to distinguish open stations open (preferred stations (preferred for stops) orfor closedstops) stations,or closed andstations, their and size their depends size depends on lines andon lines user and quantity. user quantity. Stations Stations are positioned are positioned in relation in relation to the adjacent to the adjacent urban layout, urban butlayout, the but system the system is optimized if they are close to pedestrian areas due to safety reasons. The processing speed does not depend only on vehicles, stations, or runways, because it is the exchange of information that Infrastructures 2020, 5, 88 4 of 13 is optimized if they are close to pedestrian areas due to safety reasons. The processing speed does Infrastructures 2020, 5, x FOR PEER REVIEW 4 of 13 not depend only on vehicles, stations, or runways, because it is the exchange of information that guarantees a correct and timely operation.operation. Such ch characteristicsaracteristics relate mainly to two contexts: user information and operators and systems information. The The first first is fundamental to allow passengers to choose betweenbetween the the BRT BRT system’s system’s services services concerning concerning their needs.their needs. The second The onesecond affects one the affects operation the operationof the entire of the system, entire so system, it essential so it essential to communicate to communicate accidents, accidents, vehicles, vehicles, and route and data. route The data. public The publictransport transport system issystem equipped is equipped with high with efficiency high ITefficiency and electronic IT and telecommunication electronic telecommunication devices, the devices,so-called the intelligent so-called transport intelligent systems transport (ITS), systems to ensure (ITS), such to capabilities. ensure such These capabilities. devices allowThese real-time devices allowtraffic datareal-time and communicationtraffic data and network communication control. Withnetwork regard control. to technological With regard characteristics, to technological there characteristics,are several types there of traareffi severalc light types systems, of satellite light navigators, systems, satellite or speed navigators, detectors; or moreover, speed detectors; thanks moreover,to recent , thanks to recent sensor innovations, device systems sensor have device been systems implemented have been that implemented can be installed that bothcan be in installedvehicles andboth in in infrastructure vehicles and (stations, in infrastructure lanes). Nonetheless, (stations, lanes). the accuracy Nonetheless, and precisionthe accuracy of all and the precisiondecisions of in all the the design decisions phase in andthe design concerning phase the and aspects concerning above-mentioned the aspects above-mentioned can be complicated can be to complicatedavoid delays to at 100%,avoid whichdelays forat 100%, users representwhich for the users most represent significant the inconvenience. most significant Such inconvenience. events occur Suchfor several events reasons, occur for and several not always reasons, attributable and not always to public attributable transport systems.to public Thesetransport depend systems. on variable These dependparameters on variable that are impossibleparameters to that predict. are impossible The case of to a predict. BRT system The thatcase basesof a BRT its e systemfficiency that on reservedbases its efficiencylane intersections on reserved represents lane intersections the most critical represents point. Forthe safetymost critical reasons, point. BRT For vehicles safety are reasons, constrained BRT vehiclesto operate are maneuvers constrained (valid to operate also for maneuvers non-public (va transportlid also vehicles) for non-public of deceleration, transport braking, vehicles) and of deceleration,acceleration, respectively,braking, and before, acceleration, in correspondence, respectively, and afterbefore, the in . correspondence, The aggregation and after times the intersection.for such maneuvers The aggregation create the times delay, for as such shown maneuvers in Figure 2create. the delay, as shown in Figure 2.

Figure 2. VehicleVehicle delay at intersection.

Strategies to manage and maximize such discom discomfortfort are are various, so the prioritization of of BRT vehicles at intersections can be managed passively, with the absence of signal priority and operating according toto aa pre-defined pre-defined schedule. schedule. Consequently, Consequently, it is it possible is possible to achieve to achieve a vehicle a vehicle detection detection strategy strategyboth in an both active in andan adaptiveactive and way adaptive with the way aim towith detect the in aim real-time to detect BRT in and real-time traffic vehicles. BRT and However, traffic vehicles.it is commonly However, preferred it is commonly to use transit preferred signal to priority use transit due tosignal its e ffipriorityciency. due With to recentits efficiency. innovations, With recentmany otherinnovations, solutions many have other been so studied.lutions Onehave of been them studied. consists One of implementing of them consists an algorithmof implementing named anTSPAT algorithm (Transit named Signal TSPAT Priority (Transit for Actuated Signal Timing),Priority for which Actuated was tested Timing), on a which real scenario was tested (intersection on a real scenarioin Isfahan, (intersection Iran) with Verkehrin Isfahan, In Städten-SIMulationsmodellIran) with Verkehr In Städten-SIMulationsmodell (VISSIM) traffic simulation. (VISSIM) Such traffic study simulation.objects were Such the “Freiburg study objects intersection” were the in Isfahan,“Freiburg where intersection” there is a BRT in Isfahan, station, andwhere in the there street, is a where BRT station,it is wider, and there in the are street, two BRT where runways it is wider, positioned there are at the two edges BRT thatrunways carry positioned buses in opposite at the edges directions. that carry buses in opposite directions. The results of the algorithm above-mentioned showed a more positive trend regarding off-peak hours. For off-peak hours in both for BRT system operation and environmental-economic impact, outputs were all positive. In these cases, delays were reduced by 51% with a reduction in air pollutants and fuel consumption, respectively, by 6.9% and 6.5%, and Infrastructures 2020, 5, 88 5 of 13

The results of the algorithm above-mentioned showed a more positive trend regarding off-peak hours. For off-peak hours in both for BRT system operation and environmental-economic impact, outputs were all positive. In these cases, delays were reduced by 51% with a reduction in air pollutants and fuel consumption, respectively, by 6.9% and 6.5%, and average speed increased by 78%. In contrast, peak hours of positive outcomes saw a 21% reduction in delays, the average speed increased by 26%, average fuel consumption increased by 2%, and air pollutants by 2.9% [6]. In conclusion, it has to be underlined that among the several parameters that affect the BRT system configuration, the demand analysis is the most significant. This planning phase provides the number of users, so, according to these data, the BRT system will assume various assets. The BRT configuration solutions referring to the number of passengers are shown in Table3.

Table 3. Typical BRT configuration according to demand level.

Transit Passengers per Hour per Direction Type of BRT Solution Simple bus priority, normally without physical segregation, Less than 2000 possible part-time . Segregated median busway used by direct services reducing 2000 to 8000 the need to transfer. Segregated median busway used by trunk services requiring 8000 to 15,000 transfers but benefiting from fast and operating speeds. Transit priority at intersections. Segregated median busway, with overtaking at stops; possible 15,000 to 45,000 use of express and stopping services. Use of separation at some intersections and some form of signal priority at others. This level of demand is very rare on existing bus systems. It is possible, however, to design a BRT system that would serve up to even 50,000 passengers per hour per direction. This can be Over 45,000 achieved with full segregation, double busway, a high proportion of express services and multiple stops. This capacity could also be handled by spreading the load through two or more close corridors.

3. Bus Rapid Transit (BRT) and Autonomous Vehicles The most important innovations that affect the transport and automotive sectors nowadays are represented by autonomous vehicles whose equipment can replace driver intervention. To highlight several autonomous vehicle types that have been implemented, it is possible to refer to the classification, depicted in Figure3, established by SAE (Society of Automotive Engineers). There are six levels of classification: from level zero to level two, there are vehicles with full manual control (level zero) and those with some features that allow driver assistance and partial automation (level one and level two); then level three to level five indicates vehicles that are equipped with the so-called ADAS (Advanced Driver-Assistance System) that permits autonomous performances. In these cases for a third and fourth level, a driver is required. The vehicles operate autonomously only in some circumstances, while, for level five, the vehicle can achieve full autonomy [7]. Among several benefits that would be provided by autonomous vehicles, the main ones are related to safety, considering that a high-tech system would manage driving maneuvers with shorter reaction times compared to human drivers, but also to public transport services that would achieve high efficiency due to the accuracy of the IT systems. With regard to public transport, it has to be pointed out how the ADAS operation would be more relevant for road vehicles such as buses instead of rail vehicles (, ) because while this one is hooked to a platform (predetermined trajectory), the trajectory of autonomous road vehicles would be utterly dependent on ADAS. Infrastructures 2020, 5, 88 6 of 13 Infrastructures 2020, 5, x FOR PEER REVIEW 6 of 13

FigureFigure 3. 3. VehicleVehicle automation automation levels. levels.

TakingTaking into into account account the the advantages advantages that that autonomous autonomous vehicles vehicles could could give give to to a a BRT BRT system, system, many many companiescompanies have have launched launched tests tests with with autonomous autonomous bu busesses like, like, for for instance, instance, the the East East Japan Japan Railway Railway Company’sCompany’s (JR (JR East’s) East’s) Bus Bus Rapid Rapid Transit Transit (BRT) (BRT) lines lines [8], [8], aiming aiming to to analyze analyze self-driving self-driving technologies technologies whenwhen applied applied to to bus bus transit transit primarily primarily focusing focusing on on aspects aspects such such as as keeping keeping in in lane lane and and speed speed control, control, whichwhich stronglystrongly affaffectect BRT BRT effi efficiencyciency or theor buses’the buses’ decision decision capabilities capabilities when managing when managing several scenarios. several scenarios.The cooperation The cooperation of an efficient of an system efficient like BRTsystem and like the technologicalBRT and the technological capability of ADAS capability would of provideADAS wouldan ultimate provide low-cost an ultimate solution low-cost for critical solution traffi forc issues critical and traffic emissions issues reduction and emissions in cities, reduction especially in cities,considering especially that consider it is expecteding that that it is in expected 2050, more that than in 2050, two-thirds more than of the two-thirds world’spopulation of the world’s will populationlive in cities will [9 ].live Examples in cities [9]. of autonomousExamples of autonomous bus services bus consist services mainly consist of autonomous mainly of autonomous minibuseswith a capacity with a of capacity a maximum of a ma ofximum 15 people. of 15 Theypeople. operate They operate in several in several contexts contexts like , like hospitals, parks, parks,universities, universities, , airports, and public and . public However, roads. Ho withwever, such with reduced such capacity, reduced it capacity, would be it complicated would be complicatedto implement to a implement BRT system a thatBRT is system mainly that valued is mainly for its valued high capacity for its high buses. capacity Therefore, buses. to guaranteeTherefore, a tohigh guarantee capacity a system, high capacity the solution system, would the besolution to use would a high numberbe to use of a minibuses high number that of are minibuses already able that to aredrive already on a publicable to road, drive and on toa public operate road, them and in reservedto operate lanes, them thus in reserved ensuring lanes, a significant thus ensuring efficiency a significantconsidering efficiency that with considering a high quantity that of with vehicles, a high the quantity waiting timeof vehicles, would bethe decreased waiting time due towould the high be decreasedfrequency due and to flexibility. the high Crucially,frequency toand ensure flexibility. the correct Crucially, operation to ensure of an the autonomous correct operation BRT system, of an autonomousthe infrastructures BRT system, will need the toinfrastructures be upgraded will with ne ITSed andto be sensors upgraded able with to allow ITS and the followingsensors able types to allowof communications: the following V2Itypes (vehicles of communications: to infrastructure), V2I (vehicles V2V (vehicle to infrastructure), to vehicle), and V2V V2X (vehicle (vehicle to to vehicle),everything) and [ 10V2X]. In(vehicle Figure 4to, iteverything) is possible to[10]. see In an Figure autonomous 4, it is possible bus that to works see an on autonomous a street in California. bus that works on a street in California. Infrastructures 2020, 5, 88 7 of 13 Infrastructures 2020, 5, x FOR PEER REVIEW 7 of 13

Figure 4. Example of an autonomous .

The fact that autonomous minibuses are alreadyalready operating, despite the higher capacity of autonomous buses, can be attributed to their dimensions,dimensions, safety, maintenance, and other complex reasons. Moreover, there are several tests of highhigh capacitycapacity and articulatedarticulated buses equipped with ITS and sensors that allow them to operate autonomously. A test of this kind was carried out with with a a -ART-RA-IN [[11].11]. One such 18 m long bus was fully equipped and tested on a 385 m long private road in Arganda del Rey (). To control speed and brakes, an electronically connected II/O/O board waswas used. At the same time, the was equipped with a 24-volt DC motor (150 watts) that also had an incremental optical encoder (2000 ppr) and a gear reduction box box (74:1). (74:1). Finally, obstacleobstacle detectiondetection waswas allowed, thanks to two Laser Imaging Detection and Ranging Ranging (LIDAR) (LIDAR) systems (LMS-221(LMS-221 and and LMS-291). LMS-291). The The average average speed speed during during the the test test was was between between 10 km 10/h km/h and 25 and km 25/h. Inkm/h. comparison, In comparison, 60 km /60h waskm/h reached was reached only in only a straight in a straight section. section. It has It been has observedbeen observed that the that main the challengemain challenge for autonomous for autonomous systems systems in such casesin such is represented cases is represented by the high by mass the and, high consequently, mass and, theconsequently, greater inertia, the greater which isinertia, why the which main is observations why the main showed observations longitudinal showed and laterallongitudinal maneuvers and oflateral breaking maneuvers and acceleration. of breaking Test and results acceleration. showed Te thatst results the maximum showed errorthat the that maximum exceeded error trajectory that trackingexceeded was trajectory at least 35tracking cm on was curves at withleast a35 reduced cm on radius, curves while with thea reduced all trajectory radius, error while was atthe least all 10trajectory cm. It canerror be was assumed at least that 10 such cm. errorsIt can arebe assumed considered that acceptable, such errors taking are considered into account acceptable, the bus’s elevatedtaking into dimensions account the [12 bus’s] (Figure elevated5). dimensions [12] (Figure 5). Beyond performance, another esse essentialntial benefit benefit linked to a potential BRT autonomous system is with regardregard to to capacity capacity increase. increase. This This achievement achievement is a consequenceis a consequence of the headwayof the reduction reduction between buses,between which buses, is allowedwhich is thanks allowed to thethanks CACC to the (cooperative CACC (cooperative adaptive cruise adaptive control). cruise This control). system This can perceivesystem can sudden perceive changes sudden in changes the speed in ofthe adjacent speed of vehicles adjacent faster vehicles than faster a human than driver.a human In driver. this way, In takingthis way, into taking account into thataccount vehicles that vehicles will be able will tobe brakeable to promptly, brake promptly, the required the required safety distancesafety distance while theywhile are they moving are moving will be will shorter be shorter compared compared to that to of that the human-driven of the human-driven vehicles. vehicles. Together Together with shorter with headway,shorter headway, this will this form will the form so-called the so-called platooning, plat andooning, with thisand asset,with thethis BRTasset, system the BRT will system increase will its capacity,increase its emulating capacity, that emulating of rail transit that of systems rail transit [13 ].systems [13]. Infrastructures 2020, 5, 88 8 of 13 Infrastructures 2020, 5, x FOR PEER REVIEW 8 of 13

FigureFigure 5. 5.(a ()a Tested) Tested articulated articulated bus,bus, ((bb)) innerinner road dimensions, ( (c) )bus bus trajectory trajectory analysis. analysis.

4. BRT4. BRT Systems Systems Applications Applications TheThe reduced reduced cost–benefit cost–benefit ratio ratio of implementingof implementing BRT BRT systems systems represents represents a significant a significant turning turning point forpoint several for communities,several communities, not only not in termsonly in of terms livability, of livability, but also but economic also economic gain, since gain, cities since also cities consider also theconsider urban redevelopment the urban redevelopment brought by BRT brought systems by toBRT increase systems their to international increase their attractiveness international with consequentattractiveness positive with implicationsconsequent positive from a touristimplicatio pointns from of view. a tourist A typical point exampleof view. A of typical BRT’s example benefits in a developingof BRT’s benefits country in a is developing represented country by the is represen caseted inbyPakistan, the Lahore a citycase ofin atPakistan, least eleven a city millionof at inhabitantsleast eleven where million a BRT inhabitants system waswhere activated a BRT system in 2013. was It activated operates in 2013. a reserved It operates lane locatedin a reserved on a 27 kmlane long located corridor on witha 27 km an operationallong corridor speed with ofan 26operational km/h and speed 25 stations, of 26 km/h and managesand 25 stations, a quantity and of 180,000manages daily a quantity passengers of 180,000 [14,15]. daily With passengers regard to performance, [14,15]. With regard due to to a fleetperformance, of sixty-four due buses,to a fleet there of is a headwaysixty-four ofbuses, three there minutes. is a headway In terms of of three Lahore’s minute benefits,s. In terms the of population Lahore’s benefits, density the passed population from 268 personsdensity/acre passed to 299 from persons 268 persons/acre/acre due to to the 299 increase persons/ inacre new due construction to the increase in areas in new close construction to stations. in areasIn conclusion,close to stations. from an economic point of view, there were investments of almost $140 million, creatingIn 800 conclusion, new employees from an economic [16,17]. In point , of view, the there city were of Lahore investments (Figure of6 )almost is not $140 the onlymillion, case creating 800 new employees [16,17]. In Pakistan, the city of Lahore (Figure 6) is not the only case where BRT has provided significant benefits from an economic point of view and an environmental where BRT has provided significant benefits from an economic point of view and an environmental one. For instance, Multan’s BRT system was studied to evaluate the skills and performances of hybrid one. For instance, Multan’s BRT system was studied to evaluate the skills and performances of hybrid energy-based buses. Based on DEA (data envelopment analysis), the efficiency range of 21 stations InfrastructuresInfrastructures2020 2020, 5, 5 88, x FOR PEER REVIEW 9 of9 13 of 13

energy-based buses. Based on DEA (data envelopment analysis), the efficiency range of 21 stations (except(exceptInfrastructures one one for for 2020 the the, 5 hybrid, xhybrid FOR PEER bus bus REVIEW system) system) waswas almostalmost eq equalual to to 1, 1, where where the the only only exception exception was was at9 ata of stop a13 stop wherewhere the the value value was was 0.77 0.77 [18 [18].]. energy-based buses. Based on DEA (data envelopment analysis), the efficiency range of 21 stations (except one for the hybrid bus system) was almost equal to 1, where the only exception was at a stop where the value was 0.77 [18].

FigureFigure 6.6. Lahore BRT BRT system. system.

TakingTaking into into account account thethe data about aboutFigure South South 6. Lahore America, America, BRT considering system. considering that that it is itthe is continent the continent where where the theBRT BRT system system was was first first established, established, it is it still is still the theone one in which in which there there are more are more significant significant examples examples of ofsuch such travelTaking networks; networks;into account moreover, moreover, the data it about hosts it hosts South and and is America, also is alsothe consideringoften-cited the often-cited systemthat itsystem is that the actscontinent that as actsa model where as a atthe model an atinternational anBRT international system waslevel, level,first for established, instance, for instance, the it is the“TransMilenio”still “TransMilenio”the one in which of Bogotà ofthere Bogot are()à more(Colombia) significant [19]. [The19 examples]. success The success of of TransMileniosuch travel networks; is related moreover,to the optimal it hosts outcomes and is alsoin terms the often-cited of profits duringsystem thethat first acts years as a model that covered at an of TransMilenio is related to the optimal outcomes in terms of profits during the first years that theinternational expenses oflevel, planning for instance, and servicethe “TransMilenio” provision easily of Bogotà with (Colombia)privately-operated [19]. The buses.success Such of covered the expenses of planning and service provision easily with privately-operated buses. Such advantagesTransMilenio led is to related the implementation to the optimal outcomesof other interesting in terms of BRTprofits systems during in the Colombia, first years like that the covered one in advantages led to the implementation of other interesting BRT systems in Colombia, like the one in Barranquillathe expenses [20,21]. of planning This metropolitan and service area provision had significant easily withurban privately-operated segregation and inequalitybuses. Such that [20,21]. This metropolitan area had significant urban segregation and inequality that alsoadvantages affected ledthe totransportation the implementation systems of (Figureother interesting 7). Due to BRT the systems rapid economic in Colombia, and likeurban the growth,one in alsothereBarranquilla affected was a therelevant [20,21]. transportation increase This metropolitan in systemscongestion area (Figure phenomen had7 ).significant Duea attributed to theurban rapid to segregation the economic quantity and of and privateinequality urban vehicles. growth,that thereAalso trunk-feeder was affected a relevant the BRT transportation increase service inwas congestion activatedsystems (Figure to phenomena manage 7). Due such attributed to athe situation, rapid to theeconomic connecting quantity and Barranquilla of urban private growth, vehicles. and A trunk-feederSoledadthere was along a relevant BRT a 14 servicekm increase corridor was in with activatedcongestion exclusive to phenomen manage right-of-way.a such attributed aThis situation, system,to the quantity connecting named of “Transmetro”, private Barranquilla vehicles. was and SoledadalsoA trunk-feedercharacterized along a 14 BRT kmby severalservice corridor wasfeeder with activated routes exclusive (190to manage right-of-way.km). One such of a the situation, This advantages system, connecting namedof Transmetro Barranquilla “Transmetro”, is the and free was alsoserviceSoledad characterized offered along for a by14 vehicles severalkm corridor moving feeder with from routes exclusive the (190 feeder right-of-way. km). to Onetrunk of route. This the advantagessystem, To demonstrate named of Transmetro“Transmetro”, how BRT systems is was the free serviceattractalso ocharacterized ffprivateered for investment, vehicles by several moving this feeder type from routesof BRT the (190 feedersystem km). tois One trunkcharacterized of the route. advantages To by demonstrate a public-private of Transmetro how partnership is BRT the systemsfree attractwhereservice private the offered public investment, for part vehicles deals this moving with type operational from of BRT the systemfeeder and toorganizational is trunk characterized route. To aspects demonstrate by a public-privatewhile privatehow BRT companies partnershipsystems attract private investment, this type of BRT system is characterized by a public-private partnership wheremanage the delivery public part service deals [22]. with operational and organizational aspects while private companies where the public part deals with operational and organizational aspects while private companies manage delivery service [22]. manage delivery service [22].

Figure 7. Baranquilla’s BRT system. FigureFigure 7. 7. Baranquilla’sBaranquilla’s BRT BRT system. system. Infrastructures 2020, 5, 88 10 of 13 Infrastructures 2020, 5, x FOR PEER REVIEW 10 of 13

North America has one of of the the most most recently recently inau inauguratedgurated BRT, BRT, for for example, example, Albuquerque Albuquerque (USA), (USA), which is a city with 560,218560,218 inhabitants. It is characterized by two priority lanes 20.2 km and 21.97 km long, respectively, each one with twentytwenty stations and serves 8100 daily passengers. It is not the most comprehensive system in the USA. It is usefuluseful to note that its peak frequency reaches eight bus/hourbus/hour [[23].23]. Moreover, Moreover, the highest use of BRT system systemss is not not always always linked linked to to the the size size of of continents. continents. has several cities with significantl significantlyy lower passenger numbers than European ones. In Europe, BRT is most widespread in France, being activeactive in 21 cities and with a total extension of 342 km, respectively 47.72% and 39.09% of all Europe. France’s most comprehensive system is in Lille (67 km), while the most recent is in Le Mans [23]. [23]. Considering Considering its extension in Africa, BRT was not taken up as much as in other countries since it is is only only established established in in five five cities. cities. However, However, in in Dar-es-Salaam, Dar-es-Salaam, the most recently inaugurated system dates from 2016 and consists of just one corridor that is 21 km long, but with the highest number of daily passengerspassengers in Africa, equal to 180,000. In Oceania, BRT is mainly used in , where it has an extension of 90 km and operates in three cities: Adelaide, , and the metropolitan area of . The BR BRTT system in Adelaide (Fig (Figureure8 8)) isis thethe smallestsmallest one with justjust oneone 1212 kmkm corridor. corridor. However, However, it it is is one one of of the the first first to beto be implemented implemented globally, globally, and and its line its lineis mainly is mainly characterized characterized by the by -guided the track-, bus, a system a system composed composed of a specificof a specific platform platform where where only onlythe bus the can bus drive. can drive. This typeThis of type intervention of intervention has been has used been to used avoid to the avoid introduction the introduction of private of vehiclesprivate vehiclesaltogether altogether [24]. [24].

Figure 8. Adelaide’s BRT system.

5. Discussion Discussion Considering whatwhat has has been been discussed discussed in previous in previous sections, sections, it is valuable it is tovaluable note that to the note combination that the combinationof autonomous of autonomous vehicles and vehicles BRT public and transportBRT public systems transport would systems bring would many bring benefits. many The benefits. mere Theapplication mere application of driverless of driverless vehicles would vehicles guarantee would guarantee every citizen every the citizen ability th toe move ability freely to move in the freely city, inreducing the city, the reducing number the of number vehicles of by vehicles at least by 80%. at least The potential80%. The successpotential of success this strategy of this is strategy based on is basedthe concept on the of concept vehicle of sharing vehicle by sharing users, by which users, must which be promotedmust be promoted and facilitated and facilitated mainly from mainly an fromeconomic an economic point of view,point and of view, subsequently, and subsequently, with intermodal with intermodal platform implementation. platform implementation. It is well known It is wellthat automationknown that is automation not a new conceptis not a in new metropolitan concept in public metropolitan transport public operation. transport Therefore, operation. their Therefore,application their to potential application BRT to systems potential with BRT autonomous systems with vehicles autonomous would vehicles not require would lengthy not require delays, lengthyconsidering delays, that considering globally, in that 2016, globally, there were in 2016, already there 37were cities already with automated37 cities with automated systems metro [25]. systemsFurthermore, [25]. Furthermore, it is estimated itthat is estimated the spread that of the autonomous spread of vehiclesautonomous will occurvehicles quickly, will occur facilitated quickly, by facilitatedexisting automation by existing systems automation and systems technological and te innovations.chnological innovations. Nowadays, Nowadays, the same thing the same cannot thing be cannotassumed be forassumed BRT systems. for BRT Thissystems. situation This cansituation be thoroughly can be thoroughly explained explained with a comparison with a comparison between betweencase studies case in studies in andIstanbul Cairo. and In Cairo,Cairo. theIn Cair BRTo, system the BRT was system proposed was asproposed a solution as a to solution redevelop to redevelopthe inner city the thatinner was city characterized that was characterized by a high population by a high density population of at leastdensity 21,700 of personsat least /sq.km,21,700 persons/sq.km,thus heavily inclined thus heavily to congestion. inclined Itto alsocongestion. aimed to It providealso aimed an etoffi providecient connection an efficient with connection growing with growing communities settled in the periphery. BRT was regarded as an additional solution achievable in three years and with low costs. However, the project was not realized due to a lack of Infrastructures 2020, 5, 88 11 of 13 communities settled in the periphery. BRT was regarded as an additional solution achievable in three years and with low costs. However, the project was not realized due to a lack of user trust in the bus sector and skepticism regarding the placement of reserved lanes in an area subject to congestion. In Istanbul, due to a demographic increase of 38.3% and a high number of private vehicles in circulation (4.17 million private vehicles registered), there was a serious problem linked to congestion phenomena. Accordingly, a BRT system was developed by dedicating two lanes of the city’s main to buses, thus ensuring a considerable daily capacity (30,000 passengers per hour in peak hours) with headways of 20 s. It is important to remark that the first 18.5 km long stretch of the BRT line was implemented in 2007 in just 77 days. Analyzing such cases, considering that both cities are similar in terms of demographics and , it appears that, while for Cairo the lack of user trust has blocked development, in Istanbul, where the BRT system was implemented in a context of innovation and significantly as a solution to the continuous deferrals of the realization of LRT systems, BRT has achieved excellent results. For these reasons, taking into account that in some communities such as Cairo, BRT was not successful, the application of driverless systems would make it more attractive, especially considering that there are already autonomous vehicles (level 4) capable of operating in mixed traffic. Thus, the BRT system’s operational context with reserved lanes and right-of-way would be perfectly suitable [26–30].

6. Conclusions This paper has offered an examination of some BRT systems developed worldwide, summarizing the background, general technical peculiarities, and the relationship with autonomous vehicles. Considering that, in infrastructure and civil engineering, efficiency is not the only requirement but is necessary to guarantee economic advantages, minimal environmental impacts and flexibility must be taken into account carefully. The BRT is a public transport system that reflects the requirements above-mentioned. It has developed mainly in South America, where it was implemented for the first time. Taking into account the positive implications, it has spread globally, especially in Europe. Among the innovations that have most strongly characterized BRT systems as part of the automotive sector is undoubtedly the advent of autonomous vehicles, which would amplify the already efficient and robust performance of the aforementioned public transport systems, even if only in relation to the precisions of maneuvers, and the consequent possibility to reduce the safety distances between vehicles while traveling, thus increasing their frequency. ADAS systems are now used more often for minibuses with a maximum capacity of around 15 people. Therefore, it is possible to use them in a BRT system, the advantage of which is also its high capacity. This implication could be relevant even for small communities. Nevertheless, ADAS systems have been tested with excellent results, even in high capacity and bi-articulated buses. BRT can be an upgrading solution for existing bus line systems that allow contexts with limited economic means to guarantee high-efficiency services, with significant positive implications both in economic and livability terms.

Author Contributions: The authors contributed equally to this work. All authors have read and agreed to the published version of the manuscript. Funding: This research received no external funding. Acknowledgments: This work was related to the D.D. 407 of 27 February 2018 “AIM—Attrazione e Mobilitaà Internazionale” issued by the Italian Ministry of Education, University, and Research in the implementation of Action I.2 “Mobilitaà dei Ricercatori” Asse I—PON &I 2014–2020, taking into account the written amendment procedure of the PON R&I 2014–2020, pursuant to articles 30 and 90 of Regulation (EU) 1303/2013 started on 21 February 2018 as well as the relevant implementation regulations. Conflicts of Interest: The authors declare no conflict of interest. Infrastructures 2020, 5, 88 12 of 13

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