Performance based standards II

High Capacity Transport (HCT) is part of Sweden’s attempts towards a more efficient transport system. HCT vehicles are heavier and/or longer than conventional heavy vehicles and can carry more load per vehicle, resulting in less fuel consumption and emissions. In Sweden the legal length and weight limits for heavy vehicles are 25.25 m and 64 t. Also, from April 2018, heavier vehicles up to 74 t have been allowed on parts of the road network with a new bearing capacity named BK4. Introduction of vehicles longer than 25.25m is currently under consideration. In the neighboring country, Finland, the weight limit for heavy vehicles was increased to 76 t in 2013, and longer HCT vehicles up to 34.5 m are allowed on most of the road network since 2019. After allowing HCT vehicles in Sweden, regulations concerning heavy vehicles access to road network have been modified and a PBS based regulation for 74 t vehicles have been introduced. PBS stands for performance based standards, under which the required performance from the vehicles is regulated, instead of limiting their length or weight. The purpose of the PBS II project has been to contribute to further development of the PBS scheme in Sweden and to support its implementation. One important aspect which required further investigation was the effect of tire characteristics on the performance of the HCT vehicles. Also, the assessment procedure of the HCT vehicles and a corresponding tool for it, demanded further developments. These issues have been addressed in the PBS II project, resulting in standard tire models for assessment of HCT vehicles, as well as an improved open access PBS tool.High Capacity Transport (HCT) är en del av Sveriges strävan mot ett effektivare transportsystem. HCT-fordon är tyngre och/eller längre än konventionella tunga fordon och kan bära mer last per fordon vilket resulterar i mindre bränsleförbrukning och utsläpp. I Sverige är de lagliga längd- och viktgränserna för tunga fordon 25,25 m och 64 ton. Från 2018 har även tyngre fordon upp till 74 t tillåtits på delar av vägnätet med en ny bärighet som heter BK4. Introduktion av fordon längre än 25,25 m övervägs i nuläget. I grannlandet Finland höjdes viktgränsen för tunga fordon till 76 ton år 2013 och längre fordon på upp till 34,5 m är tillåtna på större delen av vägnätet sedan 2019. Efter införandet av HCT-fordon i Sverige har reglerna för tunga fordons tillträde till vägnätet ändrats och en PBS-baserad föreskrift för 74 tons fordon har införts. PBS står för “performance based standards” eller prestandabaserade kriterier på svenska. Vid ett PBS-system specificeras kriterier för prestandanivåer som ett fordon måste uppfylla istället för att sätta gränser för fordonets längd eller vikt. Syftet med PBS II projektet har varit att bidra till vidareutvecklingen av PBS-systemet i Sverige och att stödja dess genomförande. En viktig aspekt som krävde ytterligare undersökning var effekten av däckens egenskaper på HCT-fordons prestanda. Dessutom fanns det behov av att vidareutveckla metoder och verktyg för bedömning av HCT fordon. Dessa frågor har studerats i PBS II-projektet och har resulterat i standarddäcksmodeller för bedömning av HCT-fordon, samt ett fritt tillgängligt och förbättrat PBS-verktyg

Steering Based Lateral Performance Control of Long Heavy Vehicle Combinations

In this thesis the lateral performance of heavy vehicle combinations, specifically longer combination vehicles, is discussed. The use of longer combination vehicles is promoted by their positive impact on the traffic congestion problem, as well as their economic and environmental benefits due to reduced fuel consumption and emissions. However, from a safety perspective, there are concerns about their impact on the traffic. In a heavy vehicle combination maneuvering at high speeds, lateral motions get amplified at the towed units, which causes trailer swing and large path deviation and side slip. These amplified motions are dangerous for any nearby cars as well as the vehicle combination itself and can lead to instability. The main goal of the research presented in this thesis is to develop control strategies for improving the lateral performance of heavy vehicle combinations at high speeds by suppression of amplified motions at the towed units. As a starting point, the heavy vehicle accidents are investigated and the relevant critical maneuvers are identified. Subsequently, the lateral performance of heavy vehicle combinations in the identified critical maneuvers is investigated by simulations to obtain a better understanding of the causes behind rearward amplification of motions in heavy vehicle combinations and to specify the control objectives. Accordingly, a generic controller for improving the lateral performance of heavy vehicle combinations by active steering of the towed units is developed. The developed controller is verified for various heavy vehicle combinations by simulation, with respect to the identified critical maneuvers. The verification results confirm the effectiveness of the controller and show significant reductions in yaw rates, side slip and path deviation of the towed units of the heavy vehicle combinations, up to 70%. Additionally, the robustness of the controller is evaluated by extensive analysis of its performance in various driving conditions and presence of parameter uncertainties for a sample heavy vehicle combination. Furthermore, the controller is implemented on a truck-dolly-semitrailer test vehicle and verified in a series of single and double lane changes. The experimental results approve the simulation outcomes. The developed controller can be easily implemented on steerable trailers; since it utilizes common sensors for steering input, speed and yaw rates and does not require large computing capacity. The significant improvements obtained by the developed controller can promote the use of longer combination vehicles in traffic, which will result in a reduction of traffic congestion problem, as well as substantial environmental and economic benefits

On Lateral Stability of Heavy Vehicle Combinations - Linking Accident Analysis and Vehicle Dynamics

One of the hazardous motions of heavy trucks is lateral instability which can be defined as deviation from driver intended path due to skidding of the vehicle. Lateral instability is associated with 9% of heavy trucks involved in traffic accidents, which represents a considerable figure when translated to real accidents. For instance in the US, this can be translated into about 36000 traffic accidents each year which could have been mitigated or even prevented.The objective of the research presented in this thesis is to develop reality-based lateral stability control strategies for heavy trucks. By reality-based it is meant that the control strategy should be designed to reduce heavy trucks accidents due to lateral instability andshould be evaluated in the same scope. To fulfill this objective, an analysis of heavy truck accidents based on the Large Truck Crash Causation Study database was conducted. Accident scenarios were studied and a category of critical maneuvers causing loss of control was identified. Based on the accident analysis results, relevant existing test maneuvers were adapted for trucks and compared; the sine with dwell maneuver was selected as the most suitable test for evaluation of lateral stability of heavy trucks. Furthermore, some performance measures were proposed based on a series of field tests.As the first insight into the development of lateral stability control strategies for heavy trucks, Rear Axle Steering (RAS) for a single unit truck was investigated. It was shown that by RAS, considerable safety benefits and enhancement in driver comfort can be gained

Steering Based Lateral Performance Control of Long Heavy Vehicle Combinations

In this thesis the lateral performance of heavy vehicle combinations, specifically longer combination vehicles, is discussed. The use of longer combination vehicles is promoted by their positive impact on the traffic congestion problem, as well as their economic and environmental benefits due to reduced fuel consumption and emissions. However, from a safety perspective, there are concerns about their impact on the traffic. In a heavy vehicle combination maneuvering at high speeds, lateral motions get amplified at the towed units, which causes trailer swing and large path deviation and side slip. These amplified motions are dangerous for any nearby cars as well as the vehicle combination itself and can lead to instability. The main goal of the research presented in this thesis is to develop control strategies for improving the lateral performance of heavy vehicle combinations at high speeds by suppression of amplified motions at the towed units. As a starting point, the heavy vehicle accidents are investigated and the relevant critical maneuvers are identified. Subsequently, the lateral performance of heavy vehicle combinations in the identified critical maneuvers is investigated by simulations to obtain a better understanding of the causes behind rearward amplification of motions in heavy vehicle combinations and to specify the control objectives. Accordingly, a generic controller for improving the lateral performance of heavy vehicle combinations by active steering of the towed units is developed. The developed controller is verified for various heavy vehicle combinations by simulation, with respect to the identified critical maneuvers. The verification results confirm the effectiveness of the controller and show significant reductions in yaw rates, side slip and path deviation of the towed units of the heavy vehicle combinations, up to 70%. Additionally, the robustness of the controller is evaluated by extensive analysis of its performance in various driving conditions and presence of parameter uncertainties for a sample heavy vehicle combination. Furthermore, the controller is implemented on a truck-dolly-semitrailer test vehicle and verified in a series of single and double lane changes. The experimental results approve the simulation outcomes. The developed controller can be easily implemented on steerable trailers; since it utilizes common sensors for steering input, speed and yaw rates and does not require large computing capacity. The significant improvements obtained by the developed controller can promote the use of longer combination vehicles in traffic, which will result in a reduction of traffic congestion problem, as well as substantial environmental and economic benefits

Hållbar, smart parkeringskoordinering för uppkopplade och autonoma fordon

Traffic induced by parking-spot seekers is a growing challenge and constitutes a considerable portion of the traffic in city centers. New opportunities to solve this problem are emerging by connected vehicles and infrastructure. For instance, ultrasonic and magnetic sensors are already mounted on the ceiling of many parking lots to detect the availability of a parking spot. These sensors can provide parking spot availability information in real-time. Further, traffic-aware smart sensors which can detect the movement of individual vehicles are also available in many city and highway areas. This report suggests an algorithm for a cloud-based parking service that exploits these streams of data to choose the best parking lot in a given parking area. The parking seeking problem is subject to a range of criteria that may include user, municipality and parking operator preferences. Users may have some preferences with respect to walking distance to destination. Municipalities prefer to spread the traffic to reduce congestion in the urban core. Parking operators seek to maximize parking lot utilization in order to increase the revenue on real-estate investments. To solve this problem, an optimization algorithm based on multicriteria decision making process is used. The proposed SmartPark algorithm employs a discrete Markov-chain model to demystify the future state of a parking lot. The algorithm features three modular sections: • First, a search process is triggered to identify the expected arrival time periods to all parking lots in the targeted parking area. This process utilizes smart pole data streams reporting congestion rates across the targeted parking area. • Then, a predictive analytics phase uses consolidated historical data about past parking dynamics to infer a state transition matrix, showing the transformation of available spots in a parking lot over short periods of time. • Finally, this matrix is projected against similar future seasonal periods to predict the actual vacancy of a parking lot at the arrival time.Trafik som består av sökande efter parkeringsplats är ett växande problem och utgör en avsevärd del av trafiken i stadskärnor. Nya möjligheter att lösa detta problem kommer dock finnas när fordonen är uppkopplade till infrastrukturen. Till exempel, ultraljudsensorer och magnetiska sensorer är redan monterade i taket på många parkeringshus för att detektera tillgängligheten av en parkeringsplats, och dessa sensorer kan ge information om lediga parkeringsplatser i realtid. Vidare, smarta sensorer för trafikmätning, som också kan se förflyttning av enskilda fordon, finns redan i många städer och på motorvägar. Denna rapport föreslår en algoritm till en molnbaserad parkeringstjänst som använder ovanstående typ av data för att välja den bästa parkeringen i ett visst parkeringsområde. Lösningen på problemet att välja bästa parkering omfattar en rad kriterier som kan inkludera preferenser från användare, kommuner och parkeringsbolag. Användare kan till exempel ha vissa preferenser med avseende på gångavstånd till destinationen, kommuner kan föredra att sprida trafiken för att minska trafikstockningarna i stadskärnan och parkeringsbolag försöker maximera parkeringars utnyttjandegrad för att öka avkastningen på fastighetsinvesteringar. För att lösa detta parkeringsproblem användes en optimeringsalgoritm baserad på en beslutsprocess med flera kriterier. Den föreslagna SmartPark algoritmen använder en diskret Markov-kedjemodell för att prognosticera det framtida tillståndet för en parkeringsplats. Algoritmen innehåller tre modulära delar: • Först används en sökprocess för att identifiera de förväntade ankomsttiderna på alla parkeringsplatser i det önskade parkeringsområdet. Denna process använder data från smarta stolpar som mäter trafik och trängsel inom parkeringsområdet. • Sedan görs en prediktiv analys med hjälp av sammanställda historiska data över tidigare parkeringsanvändning för att skapa en matris som visar förändringen av tillgängliga platser på en parkeringsplats över kortare tidsperioder. • Till sist används matrisen tillsammans med data om säsongsvariationer för att prediktera ledigheten av en parkeringsplats vid tiden för den beräknade ankomsten

Study of Heavy Truck Accidents with Focus on Manoeuvres Causing Loss of Control

An analysis of heavy truck accidents based on the Large Truck Crash Causation Study database with respect to loss of control is presented. Heavy truck accidents were analysed with regard to the accident type, loss ofcontrol type, critical manoeuvre, vehicle combination type and different road characteristics. Three critical manoeuvres were identified as the most commonmanoeuvres causing loss of control. Based on the accident analysis results, relevant existing test manoeuvres were adapted for trucks and compared to determine a suitable test for evaluation of yaw stability of heavy trucks on a dry and level road. The comparison was conducted on a 5DOF tractor-trailer model in Matlab-Simulink

Study of Heavy Truck Accidents with Focus on Manoeuvres Causing Loss of Control

An analysis of heavy truck accidents based on the Large Truck Crash Causation Study database with respect to loss of control is presented. Heavy truck accidents were analysed with regard to the accident type, loss ofcontrol type, critical manoeuvre, vehicle combination type and different road characteristics. Three critical manoeuvres were identified as the most commonmanoeuvres causing loss of control. Based on the accident analysis results, relevant existing test manoeuvres were adapted for trucks and compared to determine a suitable test for evaluation of yaw stability of heavy trucks on a dry and level road. The comparison was conducted on a 5DOF tractor-trailer model in Matlab-Simulink

Prestandabaserade kriterier för tunga fordon med vikt och/eller dimensioner som överskrider de angivna gränserna i direktivet 96/53/EC : en förstudie för CEDR

This report includes the gathered information in a CEDR pre-study, with the objective to list the relevant safety, manoeuvrability, infrastructure and environment related criteria for longer and/or heavier vehicles. Furthermore, research areas that should be further investigated for development of a harmonized performance based standards for assessing longer and/or heavier vehicles access to a road network, are identified.Denna rapport innehåller samlad information från en CEDR förstudie med målet att lista relevanta säkerhets-, manövrerbarhets-, infrastruktur- och miljörelaterade kriterier för längre och/eller tyngre fordon. Dessutom identifieras forskningsområden som bör utredas ytterligare för att utveckla harmoniserade prestandabaserade kriterier för bedömning av längre och/eller tyngre fordons tillgång till ett vägnät.CEDR = Conference of European Directors of RoadsKriterier för fordon och infrastruktur (PBS) för fordonståg med mått och vikt som överstiger direktiv 96/53/E

Low speed performance based standards for the Nordic countries

Performance based standards (PBS) is an effective regulator policy which can address variation complexity in vehicle combinations. This paper investigates aspects of using computer simulation and mathematical models to assess the performance of vehicle combinations in low speed manoeuvring, and in particular roundabouts. A set of 22 vehicle combinations, including existing conventional heavy vehicles as well as prospective high capacity vehicles, is used to study the effects of turn angle and road surface conditions on the friction demand and swept path measures. Simulation results suggest that the friction demand measure is dependent on the available grip. This makes it hard to interpret and may not be suitable in the PBS framework. The swept path measure is relatively unaffected by friction levels, and can hence be calculated with simple and robust expressions not considering the road interaction. However, turn angle affects the swept path measure considerably, and should be addressed when designing the PBS scheme implementation into the legislations

Prestandabaserade kriterier för tunga fordon med vikt och/eller dimensioner som överskrider de angivna gränserna i direktivet 96/53/EC : en förstudie för CEDR

This report includes the gathered information in a CEDR pre-study, with the objective to list the relevant safety, manoeuvrability, infrastructure and environment related criteria for longer and/or heavier vehicles. Furthermore, research areas that should be further investigated for development of a harmonized performance based standards for assessing longer and/or heavier vehicles access to a road network, are identified.Denna rapport innehåller samlad information från en CEDR förstudie med målet att lista relevanta säkerhets-, manövrerbarhets-, infrastruktur- och miljörelaterade kriterier för längre och/eller tyngre fordon. Dessutom identifieras forskningsområden som bör utredas ytterligare för att utveckla harmoniserade prestandabaserade kriterier för bedömning av längre och/eller tyngre fordons tillgång till ett vägnät.CEDR = Conference of European Directors of Roads</p