Calibrating the Highway Capacity Manual Arterial Travel Time Reliability Model

Tufuor, Ernest; Rilett, Laurence R.; Zhao, Li

doi:10.1061/jtepbs.0000451

Cited by 10 publications

(26 citation statements)

References 24 publications

(26 reference statements)

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“…In summary, Table 3 shows that, on average, the HCM6 methodology underestimated the reliability of the test corridors by between 8.1% and 51.2%, depending on which reliability metric was used. This range of results is not surprising because, as discussed in previous research, reliability metrics tend to measure different components of reliability and some are very insensitive to the changes or differences in the underlying TTDs (9,15). For these reasons, the authors recommend that users first examine the underlying TTD before analyzing the reliability metrics.…”

Section: Comparison Of Ttr Metricsmentioning

confidence: 63%

“…Tufuor et al proposed a statistically-based calibration approach for the HCM6 TTR methodology and this calibration methodology was applied to the nine cases (9). Note that there are several HCM6 input parameters that may be adjusted during the calibration process.…”

Section: Calibrating the Hcm6 Ttd To Empirical Ttdmentioning

confidence: 99%

“…According to Spiegelman et al, a maximum number of iterations (K) is typically used and the value is based on prior experience (14). In this paper, K, the total number of generations, was set to 60 based on prior studies (9). If the number of iterations is less than 60 the algorithm logic passes to step 5.…”

Section: Calibrating the Hcm6 Ttd To Empirical Ttdmentioning

confidence: 99%

“…Recently, it was shown that the HCM6 approach severely underestimated the TTD and associated TTR metrics on a 1.16 mi testbed in Lincoln, NE (5,6). Subsequently, it was shown that this underestimation issue could be rectified using a calibration methodology designed specifically for the HCM6 TTR methodology (9). However, this work was done on a single, relatively short (e.g., 1.16 mi) section of arterial roadway in Lincoln, NE, and used data collected using Bluetooth technology.…”

mentioning

confidence: 99%

“…The estimated TTDs are used to calculate the corresponding TTR metrics and the differences between the HCM6 and the empirical TTR metrics are quantified. Finally, the HCM6 TTR methodology is calibrated for each of the five test corridors using an approach developed by the authors (9,10). The results are presented and discussed, and recommendations for future work are provided.…”

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confidence: 99%

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Validating and Calibrating the Highway Capacity Manual Arterial Travel Time Reliability Methodology

Tufuor

Rilett

Murphy

2021

Transportation Research Record

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The 6th edition of the Highway Capacity Manual (HCM6) introduced a methodology for estimating and forecasting arterial travel time (TT) distributions (TTD) and their associated travel time reliability (TTR) metrics. Recently, it was shown that the HCM6 severely underestimated both the TTD and the TTR metrics for a test network in Lincoln, NE, U.S. Subsequently, it was shown that the underestimation issue could be eliminated through a proposed calibration methodology. Because this validation and calibration work was done on a single, relatively short section of arterial roadway there is an open research question on whether this finding applies to longer and more congested arterial roadways. The goal of this paper is to validate and calibrate the HCM6 TTR methodology on five arterial roadway testbeds that are longer and more congested than the original testbed. Empirical data from the National Performance Management Research Data Set (NPMRDS) which is managed by INRIX was used to represent the ground truth. Similar to the original study, it was found that the HCM6 TTR methodology severely underestimated the TTDs, and their respective TTR metrics, on all five testbeds. This is problematic, because the HCM6 methodology indicates that the corridors had more reliable TT than the empirical data would suggest. It was also shown that the calibration methodology eliminated this underestimation. It is recommended that users of the HCM6 TTR methodology validate and, if necessary, calibrate the model using local empirical travel data.

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Section: Comparison Of Ttr Metricsmentioning

confidence: 63%

Section: Calibrating the Hcm6 Ttd To Empirical Ttdmentioning

confidence: 99%

Section: Calibrating the Hcm6 Ttd To Empirical Ttdmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Validating and Calibrating the Highway Capacity Manual Arterial Travel Time Reliability Methodology

Tufuor

Rilett

Murphy

2021

Transportation Research Record

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Lifetime cost analysis of concrete barriers and steel guardrails

Nemati,

Haas,

Torick

et al. 2024

Sci Rep

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This study investigates the lifetime costs associated with concrete barriers and steel guardrails. We introduce a cost analysis methodology that incorporates critical factors such as construction costs, maintenance costs, exposure risks during maintenance activities, and the costs imposed to traveling public through the increased traffic and the crash outcomes. We integrate various parameters including economic factors, road geometry, general weather condition, and traffic mix to estimate a location-dependent cost for each type of barrier accurately. A software tool, named CalBarrier, was developed during this study to carry out the calculations and the comparison of lifetime cost of aforementioned barriers. An inherent strength of this research is its reliance on recent real data extracted from various databases of California Department of Transportation (Caltrans), ensuring precision and relevance in accounting for various influential factors. Drawing insights from Caltrans practices and interviews with their personnel, this study emphasizes the intricate decision-making process involved in mitigating safety risks and reducing operational expenses. Although our data originates from California, the methodology for life cycle cost analysis, and our software are applicable for regions with different socio-economic conditions by deploying user input costs, making our findings a valuable resource for other areas facing comparable challenges.

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Arterial Roadway Travel Time Reliability and the COVID-19 Pandemic

Rilett

Tufuor

Murphy

2021

J. Transp. Eng., Part A: Systems

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This paper evaluated the effect of the COVID-19 preventive orders on arterial roadway travel time reliability (TTR). A comparative analysis was conducted to examine average travel time distributions (TTD), and their associated TTR metrics, before and during the COVID-19 pandemic. Travel time data for four urban arterial corridors in Nebraska, disaggregated by peak period and direction, were analyzed. It was found that in 2020, the average TTD mean and standard deviation values for all 16 scenarios were reduced by an average of 14.0% and 43.4%, respectively. The travel time index, the planning time index, the level of travel time reliability (LOTTR), and the buffer index metrics associated with these TTDs were reduced, on average, by 14.0%, 19.7%, 3.5%, and 35.0%, respectively. In other words, whether the test corridors were more reliable during the pandemic was a function of which TTR metric was used. The paper concludes by arguing for a fundamental change in how arterial TTR is measured and reported to different user groups.

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Calibrating the Highway Capacity Manual Arterial Travel Time Reliability Model

Cited by 10 publications

References 24 publications

Validating and Calibrating the Highway Capacity Manual Arterial Travel Time Reliability Methodology

Validating and Calibrating the Highway Capacity Manual Arterial Travel Time Reliability Methodology

Lifetime cost analysis of concrete barriers and steel guardrails

Arterial Roadway Travel Time Reliability and the COVID-19 Pandemic

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