01558191

Component

https://doi.org/10.3141/2483-14

The influence of trucks on highway performance has always been of interest. However, planning studies today tend to assume that a certain percentage of the traffic stream is trucks (e.g., 5%) and to make adjustments accordingly. The Highway Capacity Manual (HCM) converts trucks into passenger car equivalents by using a passenger car equivalent factor. For the HCM, however, this situation is changing. This paper describes changes to the basic freeway section methodology that are being developed to better address truck-related issues. Specifically, new models predict the space mean speeds of autos and trucks in mixed traffic streams for a variety of road grades. Also presented is a capacity adjustment factor that allows conversion of capacity values for auto-only conditions to be transformed into equivalent capacity values for mixed traffic conditions. The methodologies are presented, their development is described, and examples are given to illustrate how the procedure works.

01587923

15-4999

English

pp 120–129

2015

Transportation Research Record: Journal of the Transportation Research Board

9780309369268

Print

Figures (8) ; Photos; References (16) ; Tables (3)

Freeways; Highway capacity; Methodology; Passenger car equivalence; Trucks; Vehicle mix

Highway Capacity Manual

Highways; Motor Carriers; Operations and Traffic Management; Planning and Forecasting; I73: Traffic Control

TRIS, TRB, ATRI

Dec 30 2014 1:40PM

• 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 in Roundabout Analyses
• 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