01558240

Component

https://doi.org/10.3141/2483-16

Trucks are not always addressed explicitly in planning studies and operational analyses, even though they are a very important part of the nation’s economic engine. Most planning studies account for trucks as a percentage of the total traffic flow. The Highway Capacity Manual (HCM) converts trucks into autos through the use of a passenger car equivalency (PCE) factor. If the PCE is 2, then a truck is assumed to be equivalent to two autos. However, trucks are beginning to receive more attention, including that in the context of capacity assessments. A recent research effort focused on developing a level-of-service assessment for trucks and for enhancing the way that the impact of trucks is taken into account on freeways, arterials, and roundabouts. This paper focuses on the roundabout aspects of that research. The three roundabout-related objectives in the project were (a) to refine the PCE values used to convert trucks into auto equivalents for the flow on roundabout approaches, (b) to recalibrate the capacity equation so that it more appropriately accounts for trucks, and (c) to develop ways to estimate truck speeds so that travel times through the roundabout could be computed. The results of these analyses are presented as well as the methodology and data employed.

01587923

15-5322

English

pp 140–147

2015

Transportation Research Record: Journal of the Transportation Research Board

9780309369268

Print

Figures (6) ; Photos; References (16) ; Tables (4)

Calibration; Highway capacity; Methodology; Passenger car equivalence; Roundabouts; Traffic flow; Travel time; Trucks

Highway Capacity Manual

Highways; Motor Carriers; Operations and Traffic Management; Planning and Forecasting; I72: Traffic and Transport Planning

TRIS, TRB, ATRI

Dec 30 2014 1:47PM

• A German Approach to Freeway Facility Evaluation
• Average Delay at Unsignalized Intersections for Periods with Variable Traffic Demand
• Calibrating VISSIM for the German Highway Capacity Manual
• Effect of an Upstream Traffic Signal on the Capacity of a Downstream Two-Way Stop-Controlled Intersection
• Evaluation of Methodologies for Analyzing Freeway Ramp Weaving
• Field-Derived Freeway Passenger Car Equivalents for Congested Conditions
• Generalized Effects of On-Street Parking Maneuvers on the Performance of Nearby Signalized Intersections
• Generating Scenarios of Freeway Reliability Analysis: Hybrid Approach
• Generic Speed–Flow Models for Basic Freeway Segments on General-Purpose and Managed Lanes in Undersaturated Flow Conditions
• Methodology to Compute Travel Time of a Roundabout Corridor
• On the Treatment of Trucks for Analysis of Freeway Capacity
• Planning-Level Methodology for Freeway Facilities
• Relationship of Lane Width to Capacity for Urban Expressways
• Risk-Taking Behavior of Left-Turners in Gap Acceptance and Its Effects on Capacity Estimation at Signalized Intersections
• Updated Commercial Truck Speed Versus Distance–Grade Curves for the Highway Capacity Manual
• Vehicular Traffic Capacity at Unsignalized Crosswalks with Probabilistic Yielding Behavior