Pan Lu

Pan Lu
North Dakota State University | NDSU · Transportation and Logistics

PhD

About

119
Publications
22,557
Reads
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1,012
Citations
Citations since 2017
95 Research Items
975 Citations
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2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
Additional affiliations
January 2015 - July 2017
North Dakota State University
Position
  • Professor (Assistant)
January 2010 - present
North Dakota State University
Position
  • Professor (Associate)
Description
  • TL 782. Highway Planning and Logistics. TL 783. Transportation Systems II. TL 731. Logistics Decision Analysis. TL 753. Transportation System Modeling.
Education
August 2005 - January 2011
North Dakota State University
Field of study
  • Transportation and Logistics

Publications

Publications (119)
Article
Full-text available
Highway rail grade crossings (HRGCs) are critical spatial locations that are of utmost importance for transportation safety because traffic crashes at these locations are often catastrophic. Compared with traditional regression models, the decision tree is more advanced in its ability to handle large data sets, deal with missing values, and not req...
Article
Full-text available
Highway-rail grade crossings (HRGCs) are where a roadway and railway intersect at the same level. Safety at HRGCs has been identified as a high-priority concern among transportation agencies, but there has been little research on the effects of HRGC geometric parameters on their safety performance. This paper evaluates the effects of HRGC geometric...
Article
Safety is a major concern of transportation planners and engineers in their design of highway rail grade crossings (HRGCs). Safety agencies rely on prediction models to allocate their crossing safety improvement resources. The prediction accuracy performance of those models is under-researched. This paper performs model forecasting accuracy compari...
Article
This paper proposes a machine learning approach, the random survival forest (RSF) for competing risks, to investigate highway-rail grade crossing (HRGC) crash severity during a 29-year analysis period. The benefits of the RSF approach are that it (1) is a special type of survival analysis able to accommodate the competing nature of multiple-event o...
Article
Full-text available
Considerable research has focused on roadway accident frequency analysis, but relatively little research has examined safety evaluation at highway-rail grade crossings. Highway-rail grade crossings are critical spatial locations of utmost importance for transportation safety because traffic crashes at highway-rail grade crossings are often catastro...
Article
The objective of this study is to quantify the impact of overweight traffic on asphalt pavement life using machine learning method for survival analysis. Traffic data and field distress measurements were collected from the long-term pavement performance (LTPP) database. A random survival forest algorithm was used to establish predictive models of l...
Article
Full-text available
With climate change and the resulting rise in temperatures, wildfire risk is increasing all over the world, particularly in the Western United States. Communities in wildland–urban interface (WUI) areas are at the greatest risk of fire. Such fires cause mass evacuations and can result in traffic congestion, endangering the lives of both citizens an...
Article
Controlling CNT dispersion has been the key challenge for CNT nanocomposites. This study investigated the dispersion, mechanical and piezoresistive properties of CNT reinforced cementitious composites using carboxymethyl cellulose (CMC) treatment by comparing with three other existing mixing methods, including direct mixing, surface treatments usin...
Article
During the past several years, the COVID-19 pandemic has had pronounced impacts on traffic safety. Existing studies found that the crash frequency was reduced and the severity level was increased during the earlier "Lockdown" period. However, there is a lack of studies investigating its impacts on traffic safety during the later stage of the pandem...
Article
The global COVID-19 pandemic has had a great impact on transportation across the United States. However, there is a lack of studies investigating the pandemic’s impact on vehicular traffic at the later stage of the pandemic. Therefore, this paper studies the change of freeway traffic patterns in two metropolitan counties in the State of Utah at the...
Article
Full-text available
The reported financial losses from railroad accidents since 2009 have been more than US$4.11 billion dollars. This considerable loss is a major concern for the industry, society, and the government. Therefore, identifying and ranking the factors that contribute to financial losses from railroad accidents would inform strategies to minimize them. To...
Article
This study aims to use traditional regression model and machine learning method to analyse the impact of traffic loading on pavement performance. Pavement condition data were obtained from pavement management systems (PMS) and axle loads of truck traffic were collected at weigh-in-motion (WIM) stations. Support vector regression (SVR) method was se...
Article
Ground-level ozone (GLO) has been widely recognized as a critical air pollutant that has the potential to induce various adverse environmental and health effects. To eliminate its hazardous impacts, the development of an accurate and effective approach to forecast the upcoming pollution concentration levels is in urgent need. Recent studies show th...
Conference Paper
Traffic density has increased exponentially in recent years, and real-time traffic flow monitoring has become necessary for areas with high-density traffic flow. It is essential to measure the number of vehicles in the road networks in order to optimize the traffic management. However, estimating traffic volume efficiently and accurately is still a...
Article
Federal Railroad Administration strictly regulates the inspection frequency of all track classes to ensure timely identification of rail defects including irregular gage which is a devastating rail geometry defect. Conventional rail inspection methods are both costly and labor-intensive, whereas existing novel technologies can be expensive and most...
Article
Around one-third of the U.S. rail network is owned and operated by shortlines (Class II and III railroads). The infrastructure conditions of these railroads are marginal, and their revenue and number of employees are insufficient. To conduct proper and timely infrastructure management, it is critical for shortlines to establish a reliable and cost-...
Article
Full-text available
Pavement condition data is important for providing information on the current state of the network and determining the needs of preventive maintenance or rehabilitation treatments. However, the condition data set is often incomplete for various reasons such as measurement errors and non-periodic inspection intervals. Missing data, especially when m...
Article
Full-text available
Transportation agencies build statistical models and predict the average crash frequency to identify hazardous road sections and make informed decisions to reduce crashes. In this paper, safety performance models (SPFs) were built and evaluated considering various pavement and roadway characteristics, including pavement friction, which is seldom av...
Article
Full-text available
It is expensive to scale existing methods of road condition monitoring for more frequent and network-wide coverage. Consequently, defects that increase ride roughness or can cause accidents will go undetected. This paper presents a method to enable network-wide, continuous monitoring by using low-cost GPS receivers and accelerometers onboard regula...
Article
Full-text available
The scientific advancements in the vehicle and infrastructure automation industry are progressively improving nowadays to provide benefits for the end-users in terms of traffic congestion reduction, safety enhancements, stress-free travels, fuel cost savings, and smart parking, etc. The advances in connected, autonomous, and connected autonomous ve...
Article
Full-text available
Pavement distresses are induced by mechanistic responses in pavement structure subjected to dynamic loads of moving vehicles. Pavement surface evenness deteriorates as pavement distresses propagate, which results in dynamic axle loads and faster pavement deterioration. It is vital to consider the dynamic axle load spectra to predict pavement deteri...
Article
Predicting the structural performance of railroad structures is a constant challenge. Numerical models are the most common technique, lately, to predict the performance of many mechanical structures including railroad trackbeds. This paper presents a detailed quantitative validation of a recently developed numerical model, known as the ADYTrack, fo...
Article
Full-text available
Accurate accident prediction for highway-rail grade crossings (HRGCs) is critically important for assisting at-grade safety improvement decision making. Numerous machine-learning methods were developed focusing on predicting accidents and identifying contributing physical and operational characteristics. A more advanced deep learning-based model is...
Article
Deteriorated track infrastructure can lead to significant consequences, such as derailment incidents, loss of revenue-service hours, reduced train operation speed, and even failure of the business. The Federal Railroad Administration (FRA) requires thorough and timely rail track inspections to keep trains operating safely. Approaches using advanced...
Article
Full-text available
Deteriorated sections decide the bearing capacity of beams. Because reinforced concrete beams are nonhomogeneous materials and often have variable sections along the beam, it is a challenge to precisely measure flexural rigidity of damage or repaired sections. This paper proposes a resonance-based non-destructive approach to identify section flexur...
Article
Introduction: Highway-rail at-grade crossings (HRGCs) are critical locations where a railway and a roadway intersect with one another. Crashes at those locations often result in fatalities and economic and social damages due to the impacts on both road and rail users. The main purpose of countermeasures at HRGCs is to permit safe and efficient rai...
Article
Carbon nanotubes (CNTs) when used as additives in cementitious materials are known to enable the piezo-responses making them smart materials. The piezo-responses can potentially be used to monitor the applied forces, stress, and the resulting performances of the associated materials. An effective and reproducible method for smart cementitious mater...
Article
Full-text available
Pavement maintenance and rehabilitation (M&R) records are important as they provide documentation that M&R treatment is being performed and completed appropriately. Moreover, the development of pavement performance models relies heavily on the quality of the condition data collected and on the M&R records. However, the history of pavement M&R activ...
Article
Full-text available
The platform of a microscopic traffic simulation provides an opportunity to study the driving behavior of vehicles on a roadway system. Compared to traditional conventional cars with human drivers, the car-following behaviors of autonomous vehicles (AVs) and connected autonomous vehicles (CAVs) would be quite different and hence require additional...
Article
Full-text available
Tracks are critical and expensive railroad asset, requiring frequent maintenance. The stress from heavy car axle loads increases the risk of deviations from uniform track geometry. Irregularities in track geometry, such as track warping, can cause an excessive harmonic rocking condition that can lead to derailments, traffic delays, and associated f...
Conference Paper
Full-text available
Pavement condition monitoring is important for scheduling maintenance activities. Approaches to gathering pavement condition data can vary from visual inspection techniques to using advanced pavement profilers. Common shortcomings of these include high costs and high skill requirements. Another method is to use accelerometer data collected from sma...
Article
Road network requires timely maintenance to keep pavement surface in good condition for reduction of fuel consumption with the limited budget. This study focused on development of pavement preservation strategies in the road network considering multi-objective optimization of agency cost and environmental impact (in terms of CO2 emission). Field da...
Conference Paper
Full-text available
The railroad industry plays a crucial role in stimulating the economic growth of a nation. Therefore, monitoring the conditions of railroad is vitally essential for ensuring railroad safety. Railroad maintenance systems have integrated advanced technologies to help inspectors detect and localize anomalies that can cause casualties and financial los...
Article
Full-text available
This paper proposes a mathematical model, the competing risks method, to investigate highway-rail grade crossing (HRGC) crash frequency and crash severity simultaneously over a 30-year period. The proposed competing risks model is a special type of survival analysis to accommodate the competing nature of multiple outcomes from the same event of int...
Article
Full-text available
The remarkable mechanical properties and piezo-responses of carbon nanotubes (CNT) makes this group of nanomaterials an ideal candidate for use in smart cementitious materials to monitor forces and the corresponding structural health conditions of civil structures. However, the inconsistency in measurements is the major challenge of CNT-enabled sma...
Article
Full-text available
Highway-rail grade crossing (HRGC) crashes continue to be the major contributors to rail causalities in the United States and have been intensively researched in the past. Data-mining models focus on prediction while dominant general linear models focus on model and data fitness. Decision makers and traffic engineers rely on prediction models to ex...
Article
Full-text available
Cracking in concrete pavements is a major concern for their performance, especially the existence of the internal bottom-up cracks. These cracks may induce water penetration in-pavement structure and foundation, resulting in-pavement degradation. Early detection of the hidden cracks in concrete pavements can expedite timely maintenance, which impro...
Article
Full-text available
Wood transportation costs have significant impacts on timber investment returns. To optimize transportation costs, the practical design of the route network is necessary for log trucks that ship wood material from timberlands to wood mills. Road conditions resulting from various road maintenance policies dramatically affect speed limits, log-truck...
Article
Fuel efficiency is an important consideration in evaluating public-sector investments in multimodal corridors. Two approaches are typically used in corridor studies to forecast railroad diesel fuel consumption: (1) system-average efficiency factors, and (2) detailed analytical estimates derived from train performance calculators. The former method...
Article
Full-text available
Passenger Car Equivalent (PCE) is essential for transportation engineering to assess heavy vehicles’ (HV) impact on highway operations and capacity planning. Highway Capacity Manual 2010 (HCM 2010) used PCE values and percent of heavy vehicles to account the impacts on both highway planning and operation, however, PCE values in the latest version o...
Article
This article focused on quantifying environmental impact of asphalt pavement preservation at construction and use stage using life-cycle assessment (LCA) approach. Preservation treatments considered in the analysis include thin overlay, chip seal, and crack seal that are typically used by highway agencies. At construction stage, there are significa...
Article
Full-text available
The non-proportionally damped system is very common in practical engineering structures. The dynamic equations for these systems, in which the damping matrices are coupled, are very time consuming to solve. In this paper, a modal perturbation method is proposed, which only requires the first few lower real mode shapes of a corresponding undamped sy...
Article
Based on the basic principle of Ritz vector superposition in structural dynamics, a semi-analytical method was proposed to solve the shear lag effect of a simply supported box girder with varying depth. In this method, the modes of vibration and its derivative of the uniform Euler beams, which had the same span and boundary conditions, were assumed...
Article
Based on the basic principle of Ritz vector superposition in structural dynamics, a semi-analytical method was proposed to solve the shear lag effect of a simply supported box girder with varying depth. In this method, the modes of vibration and its derivative of the uniform Euler beams, which had the same span and boundary conditions, were assumed...
Article
The mode perturbation method (MPM) is suitable and efficient for solving the eigenvalue problem of a nonuniform soil deposit whose property varies with depth. However, results of the MPM do not always converge to the exact solution, when the variation of soil deposit property is discontinuous. This discontinuity is typical because soil is usually m...
Article
Full-text available
Frequent network-wide monitoring of the condition of roadways and railways prevent fatalities, injuries, and financial losses. Even so, agencies cannot afford to inspect vast transportation networks using present methods. Therefore, the idea of using low-cost sensors aboard connected vehicles became appealing. However, low-cost sensors introduce ne...
Article
Full-text available
Weight data of vehicles play an important role in traffic planning, weight enforcement, and pavement condition assessment. In this paper, a weigh-in-motion (WIM) system that functions at both low-speeds and high-speeds in flexible pavements is developed based on in-pavement, three-dimensional glass-fiber-reinforced, polymer-packaged fiber Bragg gra...
Article
Full-text available
A continuous condition monitoring system to detect and localize railroad track irregularities is achievable with inertial sensors onboard revenue service trains. However, the inaccurate geospatial position estimates of GPS receivers and the non-uniform sampling of inertial sensors adds noise and reduces signal strength. Consequently, the signal-to-...
Technical Report
Full-text available
A model of investment in basic track components is estimated from 1985-2008 data for Class I railroads. Network size is measured in miles of road (MOR), while traffic is measured in revenue gross ton-miles (RGTM). In addition to MOR and RGTM, the model includes railroad indicator and time variables. The purpose of the railroad variables is to captu...
Article
Full-text available
Soil mixtures with various materials such as scraps of rubber tire, iron powder, and synthetic fibers have been widely used in civil engineering for experimental research or infrastructure construction and maintenance. However, these materials are not only expensive, but may also result in environmental concerns. In recent years, sawdust, because o...
Conference Paper
Full-text available
Regular maintenance of railroad tracks is not only essential for the proper functioning of the railway, but also significantly improves ride quality, reduces track damage, and increases track life. Deviations from the designed track geometry can result in poor ride quality and possible derailments. This research investigates the potential use of lo...
Article
Full-text available
Railroad companies spend a significant portion of their revenue on track inspections to maintain safety and maximize operational efficiency. Deviations from the designed track geometry over time could lead to poor ride quality and possible derailments. The existing approaches to track inspections are expensive and laborious. The use of low-cost sen...
Article
In this paper, train-vehicle crash risk at highway-rail grade crossings (HRGCs) is analyzed with a neural network (NN) model to return meaningful rankings of crash-contributory-variable importance based on different criteria, but also to produce dependent nonlinear contributor-crash curves with all other contributors considered for a specific contr...
Technical Report
Full-text available
Federal track safety regulations require railroads to inspect all tracks in operation as often as twice weekly. Railroad companies deploy expensive and relatively slow methods using human inspectors and expensive automated inspection vehicles to inspect and monitor their rail tracks. The current practices are not only expensive and decrease rail pr...
Article
在MTS815岩石力学试验系统上对饱和泥岩进行不同振动频率下的变幅分级循环荷载试验,研究了荷载循环次数、动应力幅值以及振动频率对泥岩滞回曲线特性、阻尼比及动弹性模量变化规律的影响;根据不同震级的等效循环次数理论,提出了可用于泥岩场地地震反应分析的非线性动力参数,并且通过不同的振动频率研究其对泥岩的非线性动力参数的影响.试验结果表明:在常幅循环加载阶段,泥岩的阻尼比与动弹性模量都随着循环次数的增加而收敛于稳定值;在变幅分级循环加载阶段,阻尼比与动弹性模量都随动应力幅值的增加而增加.轴向应变大于5×10~(-4)后,随着震级的增大,阻尼比与动弹性模量变小,变化速率变缓.随着振动频率的增大,泥岩的动弹性模量-动应变曲线上移,阻尼比-动应变曲线基本不变.
Article
Full-text available
Class I railroads operate more than 191,000 kilometers of rail line in the United States, in which they have invested $196 billion. Although these railroads are privately owned, they are regulated by the US Surface Transportation Board (STB). Some of the cost factors used by the STB in decision making are based on data from 68 to 80 years ago. Thes...
Technical Report
Full-text available
This research seeks to investigate crash severity predicting models and contributing factor explorations through the application of data mining models. There are 21 variables found to be associated with commercial truck injury severities. The importance analysis indicates the variable relative important levels for contribution. The top 11 variables...
Article
Full-text available
Prediction of bridge component condition is fundamental for well-informed decisions regarding the maintenance, repair, and rehabilitation (MRR) of highway bridges. The National Bridge Inventory (NBI) condition rating is a major source of bridge condition data in the United States. In this study, a type of generalized linear model (GLM), the ordinal...
Conference Paper
Full-text available
Positive train control (PTC) is a system that combines sensors, communications, and actuators to stop a train automatically before certain types of accidents occur. The PTC implementation requirements are part of a 2008 congressional mandate. Information about PTC benefits and costs are from reports between 2004 and 2010. Since then, the complexiti...