01558203

Component

https://doi.org/10.3141/2483-17

The freeway reliability methodology proposed for the Highway Capacity Manual, which is based on SHRP2 L08 methodology, produces an approach to scenario generation that can result in several thousand scenarios to be evaluated to estimate travel time reliability. This large number of scenarios can result in cumbersome user input, a demanding computational burden, and more important, extensive challenges posed when trying to error-check and interpret individual scenarios or to calibrate the model on the basis of real-world observations. This paper presents a novel scenario-generating methodology that accounts for multiple operating conditions. The objective of the proposed approach is to increase the quality of each scenario to make it more representative of the expected congestion patterns on the freeway. This paper shows that the new approach estimates reliability performance measures more accurately than current methods, while reducing the number of scenarios significantly. Thus, the new approach results in a more direct interpretation of results, while simultaneously relaxing many assumptions in the present approach to scenario generation and decreasing biases and errors. The proposed approach uses three core mathematical schemes: (a) a deterministic mathematical model for demand generation and scheduled work zones, (b) a Monte Carlo simulation for incident and weather events, and (c) an optimization algorithm to maximize similarities between the generated set of scenarios and the population of all scenarios. A comparison of results between the proposed method and the SHRP 2 Project L08 approach confirms that the proposed approach yields a higher level of accuracy in matching observed freeway reliability performance measures.

01587923

15-5000

English

pp 148–159

2015

Transportation Research Record: Journal of the Transportation Research Board

9780309369268

Print

Figures (3) ; References (15) ; Tables (1)

Forecasting; Freeways; Highway capacity; Mathematical models; Reliability; Traffic congestion; Traffic forecasting; Travel time

Highway Capacity Manual

Highways; 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
• 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
• 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