This chapter uses trucking firm-level information to address the paucity of multivariate analysis accounting for the safety effect of various types of truck driver compensation and firm financial performance. Using negative binomial regression models, we find that small firms with high liquidity are correlated with better safety performance. Likewise, small firms that devote a higher share of their revenues to labor expenses tend to have better safety outcomes. Although the dataset is limited in many ways, these associations suggest that small firms may be particularly sensitive to...
In this paper, we study the routing of commercial electric trucks through an application of distributionally robust optimization (DRO) for route planning and dispatch. This approach aims to minimize total cost of operation for the fleet, and considers the variability in energy consumption due to uncertain road conditions, traffic, weather and driving behavior. Furthermore, we augment the distributionally robust energy minimizing vehicle routing problem by learning the energy efficiency distribution over a horizon. We show that convergence to the true distribution is achieved while learning...
The Freeway Service Patrol (FSP) is an incident management program implemented by Caltrans, the California Highway Patrol and local partner agencies to quickly detect and assist disabled vehicles and reduce non-recurring congestion along the freeway during peak commute hours. The first FSP program was piloted in Los Angeles, and was later expanded to other regions by state legislation in 1991. As of June 2018, there were fourteen participating FSP Programs operating in California, deploying 328 tow trucks and covering over 1,823 (centerline) miles of congested California freeways. The...
Freeway service patrols (FSPs) are a popular means of incident management and control. The authors address the question of the correct placement of FSP tow trucks as a scarce resource allocation problem. They present a methodology for determining where to place FSP tow trucks so as to maximize the expected reduction in congestion. They illustrate this approach using the I-880 database.
An algorithm for real-time estimation of truck traffic in multilane freeways was proposed. The algorithm used data from single loop detectors--the most widely installed surveillance technology for urban freeways in the United States. The algorithm worked for those freeway locations that have a truck-free lane and exhibit high lane-to-lane speed correlation. These conditions are met by most urban freeway locations. The algorithm produced real-time estimates of the truck traffic volumes at the location. It also can be used to produce alternative estimates of the mean effective vehicle length...
An algorithm for real time estimation of truck traffic in multi-lane freeway is proposed. The algorithm uses data from single loop detectors-the most widely installed surveillance technology for urban freeways in the US. The algorithm works for those freeway locations that have a truck-free lane, and exhibit high lane-to-lane speed correlation. These conditions are met by most urban freeway locations. The algorithm produces real time estimates of the truck traffic volumes at the location. It can also be used to produce alternative estimate of the mean effective vehicle length, which can...
This paper describes the methodology and findings for developing improved passenger car equivalent (PCE) factors for trucks at signalized intersections on the basis of field data and simulation modeling. The Highway Capacity Manual 2010 (HCM 2010) assumes a single PCE value of 2.00 for trucks at traffic signals. The proposed truck PCE values are sensitive to the proportion of trucks, truck type, and intersection’s approach grade. It is recommended that the current HCM 2010 approach of computing the heavy vehicle and grade effects on saturation flow rates independently be replaced with a...
This report presents the results of its performance assessment of the feasibility of applying cooperative vehicle- highway automation systems (CVHAS) to bus transit and freight movements in the metropolitan Chicago area. CVHAS are systems that provide driving control assistance or fully automated driving and are based on information about the vehicle's driving environment that can be received by communication from other vehicles or from the infrastructure, as well as from their own on-board sensors. The Chicago Central Area is equipped with rail transit, commuter rail and bus transit...
The Highway Capacity Manual is a major reference for evaluating the capacity and quality of service of road facilities. However, it holds the assumption that lanes perform equally, which can result in inaccuracies in performance estimation. The main purpose of this research is to develop a series of models for estimating flows and speeds by lane for various types of freeway segments, including basic, merge, and diverge types. These models consider the demand-to-capacity ratio, the presence of trucks, grade, and the presence of upstream and downstream ramps. To predict lane performance...
Cooperative adaptive cruise control (CACC) systems have the potential to improve traffic flow and fuel efficiency, but these effects are challenging to estimate. This paper reports the development of a micro-simulation model to represent these impacts for heavy trucks using CACC when they share a freeway with manually driven passenger cars. The simulation incorporates automated truck-following models that have been derived from experimental data recorded on heavy trucks driven under CACC, adaptive cruise control (ACC), and conventional cruise control (CC). The simulation includes other...
