Truck Configurations Research Articles

Overview of Global Long-Distance Road Transportation of Industrial Roundwood

The aim of the study was to provide a comprehensive overview of global long-distance road transportation of industrial roundwood. The study focused on the maximum gross vehicle weight (GVW) limits allowed with different timber truck configurations, typical payloads in timber trucking, the road transportation share of the total industrial roundwood long-distance transportation volume, and the average long-distance transportation distances and costs of industrial roundwood. The study was carried out as a questionnaire survey. The questionnaire was sent to timber transportation logistics experts and research scientists in the 30 countries with the largest industrial roundwood removals in Europe, as well as selected major forestry countries in the world (Argentina, Australia, Brazil, Canada, Chile, China, Japan, New Zealand, South Africa, Türkiye, the United States of America and Uruguay) in February 2022, and closed in May 2022. A total of 31 countries took part in the survey. The survey illustrated that timber trucking was the main long-distance transportation method of industrial roundwood in almost every country surveyed. Road transportation averaged 89% of the total industrial roundwood long-distance transportation volume. Timber truck configurations of 4 to 9 axles with GVW limits of around 30 tonnes to over 70 tonnes were most commonly used. The results indicated that higher GVW limits allowed significantly higher payloads in timber trucking, with the lowest payloads at less than 25 tonnes, and the highest payloads more than 45 tonnes. The average road transportation distance with industrial roundwood was 128 km, and the average long-distance transportation cost in timber trucking was €11.1 per tonne of timber transported. In the entire survey material, there was a direct relationship between transportation distance and transportation costs and an inverse relationship between maximum GVW limits and transportation costs. Consequently, in order to reduce transportation costs, it is essential to maximise payloads (within legal limits) and minimise haul distances. Several measures to increase cost- and energy-efficiency, and to reduce greenhouse gas emissions in road transportation logistics, are discussed in the paper. On the basis of the survey, it is recommended that up-to-date statistical data and novel research studies on the long-distance transportation of industrial roundwood be conducted in some countries in the future.

County Transportation Officials’ Perceptions of Timber Transportation Economic Importance, Infrastructure Impact, and Weight Limits in Georgia, USA

Log truck gross vehicle weight (GVW) limits in the US state of Georgia are among the lowest of any timber-producing state in the US and are far below GVW limits in countries such as Australia, Canada, Finland, and Sweden. In the state of Georgia, log trucks travel on county and state roads between harvest sites and forest industry mills. Most county roads were not constructed to support heavy trucks and so log trucks may damage these roads, even at the low GVW limits allowed in Georgia. Local governments sometimes enact timber harvesting ordinances to constrain timber transportation and often oppose efforts to increase GVW limits. The purpose of this study was to document local transportation officials’ perceptions of timber harvesting and transportation and to measure their support or opposition to alternative log truck weights and configurations. A telephone survey of county transportation superintendents or their equivalent was conducted in Georgia during the summer of 2020. Forty-three county officials responded to the survey, yielding a response rate of 43%. Ninety-eight percent of respondents reported that timber harvesting was important to their local economy, and 86% agreed that local governments were cooperative with log truck owners. County officials were concerned about damage from overweight log trucks and mud on public roads. The average preferred GVW and tandem axle weight limits were approximately 10% lower than the existing limits. County officials opposed six- and seven-axle 45,359 kg (100,000 lbs) GVW configurations but did support allowing log trucks to operate on interstate highways at current state weight limits. Findings suggest that logging businesses and mills should focus on improving compliance with weight laws, improving the condition of log trucks, and maintaining or improving relationships with the public and local government officials.

The impact of truck platooning action on asphalt pavement: a parametric study

ABSTRACT Partially/fully self-driven trucks in platoon configurations promise to increase transport efficiency, reduce fuel consumption/gas emissions and improve road safety through the use of connectivity technologies and automated driving support systems. However, truck platooning means the introduction of new types of loads on pavements which are characterised by: multiple loads, generated by the multi-axle configurations of the different trucks forming the platoon, traffic channelisation by the reduction of the lateral deviation of the trucks, and reduced inter-truck time gaps, which may reduce the self-recovery capacity of asphalt concrete materials, reducing the pavement service life. In this context, this study presents a parametric analysis carried out to evaluate a pavement structure subjected to several platoon truck configurations. The results of the study indicated that to keep the same pavement structural response as for individual trucks, it is possible to act on the following parameters in the platoon configuration: traffic distribution along the year and along the time of the day (avoiding traffic at higher temperatures), percentage of platoon penetration in the daily and annual traffic, level of loading of the trucks, number of trucks in platoon configuration, wandering, and inter-truck time-gaps/distances.

Fatigue Life Predictions for a European Pavement Test Section Subjected to Individual and Platoon Truck Configurations

Truck platooning for the transportation of loads is a strategy recently proposed by the automotive sector to cope with traffic congestion, fuel consumption, and operational costs. This new way of configuring trucks changes the typical pressures pavements structures experience. For this reason, the research efforts of the pavement sector should be aligned with the automotive sector to propose road-friendly platoon configurations. This is one of the objectives of the European project ENSEMBLE. ENSEMBLE, as indicated by its acronym, works on ENabling SafE Multi-Brand pLatooning for Europe. In this context, the present study presents a real scale test done in the Applus IDIADA facilities to evaluate the fatigue behavior of a pavement structure subjected to individual and platoon truck configurations. The effects of parameters such as traffic distribution through the year and by time of day, percentage of platoons, truck loads, number of trucks in platoon configuration, lateral wandering, and inter-truck distances were evaluated. The study’s findings revealed that the reduced rest times between trucks in the platoon configuration reduce the recovery time of the asphalt layers, increasing the fatigue damage to the pavement at high temperature conditions. This underlines the need for further research to allow the proper implementation of truck platoons. For example, research is needed to define strategies to make truck platoon configurations more pavement-friendly and analyze the costs associated with the changes in the required road maintenance/rehabilitation treatments, among others.

Impact of mountainous interstate alignments and truck configurations on rollover propensity

Introduction: Combined horizontal and vertical alignments are frequently utilized in mountainous interstates in Wyoming. The roll stability of trucks on these challenging terrain conditions is of great concern for transportation officials. The impact of curve characteristics combined with truck configurations has not been considered in the literature due to data availability issues related to the weight and Center of Gravity (CG) payload height of trucks. Method: High-fidelity vehicle dynamics simulation modeling is employed to investigate the rollover propensity of trucks navigating curves of varying geometric design and truck characteristics. A multinomial regression model was then developed to further quantify the impact of these key factors and the effect of their interactions on rollover safety margins. Results: It was shown that complying with the assigned speed limits of the curved roadways is not enough to navigate a curve without experiencing a rollover under some circumstances. The CG payload height and the operating speeds have the highest impact on the safety margins of a truck rollover. Steeper downgrades would amplify the impact of the gross weight of a truck. Tighter curves would also raise the impact of the truck configurations. Conclusions: This study assessed the curve speed limits and revealed that the exciting approach to assigning safe speed limits should be modified according to the aforementioned factors. For the first time, findings from this study shed light on the direction and magnitude of the impact of the truck configurations coupled with curve features that contribute to truck rollover safety margins. Practical Applications: This study revealed the impact of truck configurations on the roll stability of trucks and pointed out critical cases that should be treated very cautiously by drivers. This assists transportation agencies in assigning more appropriate speed limits of curved roadways according to truck conditions.

Deep Ensemble Neural Network Approach for Federal Highway Administration Axle-Based Vehicle Classification Using Advanced Single Inductive Loops

The Federal Highway Administration (FHWA) vehicle classification scheme is designed to serve various transportation needs such as pavement design, emission estimation, and transportation planning. Many transportation agencies rely on Weigh-In-Motion and Automatic Vehicle Classification sites to collect these essential vehicle classification counts. However, the spatial coverage of these detection sites across the highway network is limited by high installation and maintenance costs. One cost-effective approach has been the use of single inductive loop sensors as an alternative to obtaining FHWA vehicle classification data. However, most data sets used to develop such models are skewed since many classes associated with larger truck configurations are less commonly observed in the roadway network. This makes it more difficult to accurately classify under-represented classes, even though many of these minority classes may have disproportionately adverse effects on pavement infrastructure and the environment. Therefore, previous models have been unable to adequately classify under-represented classes, and the overall performance of the models is often masked by excellent classification accuracy of majority classes, such as passenger vehicles and five-axle tractor-trailers. To resolve the challenge of imbalanced data sets in the FHWA vehicle classification, this paper constructed a bootstrap aggregating deep neural network model on a truck-focused data set using single inductive loop signatures. The proposed method significantly improved the model performance on several truck classes, especially minority classes such as Classes 7 and 11 which were overlooked in previous research. The model was tested on a distinct data set obtained from four spatially independent sites and achieved an accuracy of 0.87 and an average F1 score of 0.72.

Assessment of commercial truck driver injury severity based on truck configuration along a mountainous roadway using hierarchical Bayesian random intercept approach

For the last decade, disaggregate modeling approach has been frequently practiced to analyze truck-involved crash injury severity. This included truck-involved crashes based on single and multi-vehicles, rural and urban locations, time of day variations, roadway classification, lighting, and weather conditions. However, analyzing commercial truck driver injury severity based on truck configuration is still missing. This paper aims to fill this knowledge gap by undertaking an extensive assessment of truck driver injury severity in truck-involved crashes based on various truck configurations (i.e. single-unit truck with two or more axles, single-unit truck pulling a trailer, semi-trailer/tractor, and double trailer/tractor) using ten years (2007–2016) of Wyoming crash data through hierarchical Bayesian random intercept approach. The log-likelihood ratio tests were conducted to justify that separate models by various truck configurations are warranted. The results obtained from the individual models demonstrate considerable differences among the four truck configuration models. The age, gender, and residency of the truck driver, multi-vehicles involvement, license restriction, runoff road, work zones, presence of junctions, and median type were found to have significantly different impacts on the driver injury severity. These differences in both the combination and the magnitude of the impact of variables justified the importance of examining truck driver injury severity for different truck configuration types. With the incorporation of the random intercept in the modeling procedure, the analysis found a strong presence (24%–42%) of intra-crash correlation (effects of the common crash-specific unobserved factors) in driver injury severity within the same crash. Finally, based on the findings of this study, several potential countermeasures are suggested.

Safe Platooning Headways on Girder Bridges

Truck platooning—digitally linking two or more trucks to travel in a closely spaced convoy—is an emerging technology with the potential to save fuel and reduce labor. A framework is described to determine how much a platoon permit load might be increased above Federal Bridge Formula B legal limits, given strict control over the load characteristics and operational tactics. Soon, platoons are expected to advance not only with respect to traffic operations but also in their ability to weigh and report axle weight and spacing, functioning as mobile weigh-in-motion vehicles. Consequently, platoon live load statistics (bias and coefficient of variation) can differ from code assumptions, and are perhaps controllable, which poses a significant opportunity with respect to operational strategies. A parametric study is presented that examined safe headways between platooning trucks, considering different girder spacings, span lengths, numbers of spans, types of structure, truck configurations, numbers of trucks, and adjacent lane loading scenarios. The Strength I limit state was evaluated for steel and prestressed concrete I-girder bridges optimally designed using load and resistance factor design. Reliability indices, β, were calculated for each load case based on Monte Carlo simulation. Summary headway guidance was developed and is presented here to illustrate potential safe operational strategies for varying truck weights and platoon live load effect uncertainties.

Retrospective Longitudinal Study of the Impact of Truck Weight Regulatory Changes on Operating Gross Vehicle Weights

Three primary policy changes on truck size and weight occurred in Canada over the past five decades: the 1974 Western Canadian Highway Strengthening Program, the 1988 Roads and Transportation Association of Canada Memorandum of Understanding on Heavy Vehicle Weights and Dimensions, and ongoing special permitting of longer combination vehicles. These regulatory changes influenced the gross vehicle weight (GVW) of the predominant truck configurations operating on principal Canadian highways. Using a unique time-series of truck weight data, this retrospective longitudinal study contributes insights about the magnitude and timing of the impacts of truck weight regulatory changes on operating GVWs that address current knowledge gaps and persistent uncertainties in models used to predict and evaluate truck weight regulatory changes. The analysis reveals that carriers hauling heavy (i.e., weigh-out) commodities adapt immediately to increases in GVW limits if there is no need to purchase new vehicles. When a regulatory change coincides with the introduction of a new, more productive vehicle configuration, the uptake of the new vehicle lags behind the regulatory change by a few years. Finally, configurations exhibit different GVW distributions and responses to increased GVW limits depending on whether the configurations are well suited for hauling weigh-out or cube-out commodities. This differential response demonstrates how regulations facilitate fleet diversity within the trucking industry’s approach to the road freight transport task.

Use of modelling to compare the impact of roadside drying of Pinus radiata D.Don logs and logging residues on delivered costs using high capacity trucks in Australia

Forest biofuel delivered costs are generally uncompetitive with fossil fuels. Drying forest biofuel can potentially reduce delivered costs through weight reductions and net calorific value increases.The study examined the impact of roadside drying (RD) and use of high-volumetric capacity trucks on delivered costs of Pinus radiata pulp-logs and logging residue (LR) chips supplying a gasification plant. Five truck configurations: 6-axle semi-trailers; 9-axle B-doubles; proposed high-volumetric (HV) capacity versions of these trucks (HV semi-trailers and B-doubles); and 11-axle pocket road trains (PRT), were investigated across six supply areas using a forest biomass supply chain tool.Without RD all truck configurations were weight limited transporting logs, and all (except HV semi-trailers and B-doubles) were volume limited transporting LR chips. Post-RD all truck configurations were volume limited transporting logs or LR chips, (except HV B-doubles transporting logs).RD considerably reduced delivered costs: PRT (22%), B-doubles (24%), semi-trailers (25%) for logs and PRT (28%), B-doubles (29%), semi-trailers (30%) for LR chips. Delivered cost differences between truck configurations reflected transport cost differences.Without RD, truck trips transporting log were directly related to truck weight capacity. Additional volumetric capacity enabled HV semi-trailers and B-doubles to transport 6% and 4% more LR chips than standard versions, respectively, with equivalent truck trip reductions. RD weight reductions were: logs (33%); LR chips (53%), with consequent reductions in truck trips. PRTs required fewest truck trips to transport logs and LR chips without RD and the second fewest for logs post-RD due to their high weight and volumetric capacities.

The influence of gross vehicle weight (GVW) and transport distance on timber trucking performance indicators – Discrete event simulation case study in Central Finland

ABSTRACT Today, timber trucks of gross vehicle weight (GVW) up to 76 tonnes are allowed to operate on Finnish roads from roadside landings to mills. Reducing trucking costs and exhaust gas emissions have been the dominant reasons for the increased GVWs of timber trucks. A discrete-event simulation (DES) method was used to compare the impact of the truck and payload size, trucking distance, and timber assortment lengths on trucking performance indicators (e.g., productivity, energy efficiency, and costs of trucking) in the procurement area of a case logistic company operating in Central Finland. The studied truck sizes were 68, 76 and 84 t, of which the 76-t trucks dominate timber trucking in Finland. Over a transport distance of approx. 105 km with an average assortment length of 4.2 m, 76-t trucks had 9% higher and 12% lower productivity (m3/100 km), 1% lower and 4% higher fuel consumption (l/m3) and 4% lower and 6% higher trucking cost (€/m3) compared to 68- and 84-tonner options, respectively. The improvement in regards to previous indicators was clearly bigger for the 76-tonner than the 68-tonner if the trucked wood assortments were lengthened to 5.0 m. The differences in cost and fuel efficiency as well as annual trucking volumes were increased as a function of the trucking distance, when comparing the truck configurations with different GVWs and payloads. To conclude, the tendency of the size increase in GVWs in timber trucking in Finland can be justified in light of the study results.

Gaussian Mixture Model to Characterize Payload Distributions for Predominant Truck Configurations and Body Types

AbstractThis article develops and applies a Gaussian mixture modeling approach to characterize payload distributions and calculate mean payloads for the 14 predominant axle configuration–body type ...

Automatic generation of truck configurations for bridge load ratings in the state of North Carolina

This paper describes a methodology to automatically generate truck configurations based on state statutes that regulate axle weights of legal vehicles. Axle weights of legal vehicles are generally used to load rate bridge structures. The particular methodology described in this paper is based on the North Carolina General Statute. The paper also describes the functionality of the computer program that generates truck configurations based on the statute. The computer program constituted a deliverable to the North Carolina Department of Transportation (NCDOT) under grant FHWA/NC/2017–07.

Reliability Assessment of Steel Bridges for Specialized Hauling Vehicles

Specialized hauling vehicles (SHVs) are short heavy trucks within the legal weight limits but induce higher load effects than routine commercial loads. The Manual for Bridge Evaluation (MBE) adopted a series of single-unit trucks (SUs) to represent this type of vehicle. However, the SUs were introduced without rigorous reliability-based analysis due to the lack of data on SHVs. With the availability of vast amounts of data on weigh-in-motion (WIM) truck weights and configurations, the reliability of steel bridges under the SHVs should be evaluated in a more robust and quantitative manner. Through the utilization of WIM data, the authors quantified the SHVs in terms of percentages of SHVs among all truck traffic, daily average counts of SHVs, and number of axles. The gross vehicle weights (GVWs) and typical configurations of SHVs were investigated. In addition, their load effects were determined and normalized by the corresponding SUs. The maximum live loads corresponding to a return period of 5 years were also extrapolated using normal probability paper (NPP). To evaluate the effectiveness of current load-rating procedures for SHVs, the authors investigated the relationship between the load-rating factors and the corresponding reliability indices for existing bridges using the developed live load parameters based on the WIM data. Results indicated that the current live load factors were not able to provide a uniform and appropriate reliability index at different average daily truck traffic (ADTT) scenarios. This paper thus proposes new live load factors and weight adjustments of SU trucks to provide an adequate and uniform safety margin for the evaluation of steel bridges.

A MECHANISTIC-EMPIRICAL IMPACT ANALYSIS OF DIFFERENT TRUCK CONFIGURATIONS ON A JOINTED PLAIN CONCRETE PAVEMENT (JPCP)

Until the last decade, the 1993 American Association of State Highway and Transportation Officials (AASHTO) design guide has been traditionally used for the design of flexible and rigid pavements in the USA and some parts of the world. However, because of its inability to meet the new traffic and material challenges, a Mechanistic Empirical Pavement Design Guide (MEPDG) was introduced based on an NCHRP 1-37 A study conducted in 2004. This study used the MEPDG software and associated models to determine, through comparative truck damage analysis, the effects of nine different truck configurations on a 12 inch-jointed plain concrete pavement (JPCP). The study recorded truck damages at the end of each analysis period (40 years) and comparatively analyzed the relative pavement damage in terms of fatigue cracking, faulting, and surface roughness. The results indicated that the most critical damage to the concrete pavement was caused by truck cases with high and uneven load distribution and relatively smaller size axles group (e.g. tandem). Other key findings included the following; (1) increase in damage when the truckloads were shifted between the same size axles, (2) decrease in truck damage when the truckloads were shifted from tandem axle to quad axles, and (3) no change in truck damage when the axle spacing was increased between wheels of a quad axle.

Battery Dimensioning and Life Cycle Costs Analysis for a Heavy-Duty Truck Considering the Requirements of Long-Haul Transportation

The use of heavy-duty battery electric trucks for long-haul transportation is challenging because of the required high energy amounts and thus the high capacity of traction batteries. Furthermore a high capacity battery implies high initial costs for the electric vehicle. This study investigates the required battery capacity for battery electric trucks considering the requirements of long-haul transportation in Germany and compares the life cycle costs of battery electric trucks and conventional diesel trucks in different transportation scenarios. The average consumption is simulated for different battery electric truck configurations on the main German highways and transportation scenarios incorporating battery charging during driver rest periods. The results show that in average case the required battery would restrict the payload to only 80% of a usual diesel truck payload that might be acceptable considering the statistical payload use. The life cycle costs in the examined scenarios also considering the charging infrastructure show that battery electric trucks can already perform on the same costs level as diesel trucks in certain scenarios.

Regulations governing the operation of longer combination vehicles in Canada

The permits governing longer combination vehicle (LCV) activity in Canada aim to leverage LCV productivity advantages relative to other truck configurations while subjecting LCV operations to stringent regulatory controls. As of 2016, nine of the 13 provinces and territories permit LCV operations on a 17 000 km highway network. This article synthesizes LCV regulations in these jurisdictions within five categories: (i) carrier permit requirements, (ii) truck size and weight limits, (iii) equipment requirements, (iv) operating conditions, and (v) driver qualifications. While jurisdiction-specific differences remain, the synthesis reveals regulatory uniformity at the regional level. The article identifies how these regulations influence highway design, operations, and management decisions concerning the accommodation of LCV performance characteristics, the spatial and temporal control of LCV operations, the eligibility of drivers and carriers to operate LCVs, and opportunities for regulatory harmonization. As LCV activity increases, the need to formally consider the characteristics of LCVs within these decisions becomes more apparent.

WIM-Based Live-Load Model for Advanced Analysis of Simply Supported Short- and Medium-Span Highway Bridges

The accuracy of bridge system safety evaluations and reliability assessments obtained through refined structural analysis procedures depends on the proper modeling of traffic load effects. While the live-load models specified in AASHTO procedures were calibrated for use in combination with approximate analysis methods and load-distribution factors commonly used in the United States, these existing models may not produce accurate results when used in association with advanced finite-element analyses of bridge structures. This paper proposes a procedure for calibrating appropriate live-load models that can be used for advanced analyses of multigirder bridges. The calibration procedure is demonstrated using actual truck data collected at a representative set of weigh-in-motion (WIM) stations in New York State. Extreme value theory was used to project traffic-load effects to different service periods. The results are presented as live-load models developed for a 5-year typical rating interval and for a 75-year design life. The outcome of the calibration indicates that maximum traffic-load effects can be calculated using finite-element models with the help of a single truck for short to medium one-lane multigirder bridges and two side-by-side truck configurations for multilane bridges. The proposed analysis trucks have axle configurations of the standard AASHTO 3-S2 and Type 3 legal rating trucks with appropriate factors to amplify their nominal weights. The amplification factors reflected the presence of overweight trucks in the traffic stream and the probability of multiple presence. The proposed live-load models are readily implementable for deterministic refined analyses of highway bridges and for evaluating the reliability of bridges at ultimate limit states considering the system’s behavior.

Estimation of Average Payloads from Weigh-in-Motion Data

Average payloads define the ton-to-truck conversion factors that are critical inputs to commodity-based freight forecasting models. However, average payloads are derived primarily from outdated, unrepresentative truck surveys. With increasing technological and methodological means of concurrently measuring truck configurations, commodity types, and weights, there are now viable alternatives to truck surveys. In this paper, a method to derive average payloads by truck body type and using weight data from weigh-in-motion (WIM) sensors is presented. Average payloads by truck body type are found by subtracting an estimated average empty weight from an estimated average loaded weight. Empty and loaded weights are derived from a Gaussian mixture model fit to a gross vehicle weight distribution. An analysis of truck body type distributions, loaded weights, empty weights, and resulting payloads of five-axle tractor trailer (FHWA Class 9 or 3-S2) trucks is presented to compare national and state-level Vehicle Inventory and Use Survey (VIUS) data and the WIM-based approach. Results show statistically significant differences between the three data sets in each of the comparison categories. A challenge in this analysis is the definition of a correct set of payloads because the WIM and survey data are subject to their own inherent misrepresentations. WIM data, however, provide a continuous source of measured weight data that overcome the drawback of using out-of-date surveys. Overall, average payloads from measured weights are lower than those for the national or California VIUS estimates.

Using systematic indices to relate traffic load spectra to pavement performance

The application of truck axle load spectra in the Mechanistic Empirical Pavement Design Guide (MEPDG) has brought great advancement in pavement design through quantifying pavement accumulated damage due to individual axle loads. However, how to relate the truck axle load volume and spectra directly to pavement performance remains a practical challenge for pavement engineers. This paper presents a systematic index approach to this issue that characterizes three aspects of traffic loading to pavement performance: volume, load, and damage. Four summary indices were investigated in this study: cumulative truck volume (CTV), cumulative truck load (CTL), equivalent single axle load (ESAL), and relative pavement performance impact (RPPI). The involved concepts and calculation procedures were first introduced, followed by a numerical evaluation analysis of 30 axle load spectra, 18 vehicle class distributions, 2 truck configurations, and 2 pavement types. To demonstrate how these summary indices could be used, a case study was presented. Overall results suggested that the systematic indices introduced in this study had a clear relationship with pavement performance, so it could be used to assist engineers in many ways such as comparing different load spectra, communicating between engineers, and understanding the relationship between traffic and pavement performance for a specific design at any point in time.