Development and Calibration of a Global Geometric Design Consistency Model for Two-Lane Rural Highways, Based on the Use of Continuous Operating Speed Profiles

Camacho, Esteban; Javier, Francisco

doi:10.4995/thesis/10251/48543

Cited by 4 publications

(7 citation statements)

References 43 publications

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“…The new safety performance function was compared with several safety performance functions calibrated from the consistency parameters proposed by Polus and Mattar-Habib (2004), Garach et al (2014), andCamacho-Torregrosa (2015). As a result, the new model showed the lowest AIC value and a closer relationship with the observed crashes.…”

Section: Discussionmentioning

confidence: 99%

“…The new consistency model has been compared with the global consistency models developed by Polus and Mattar-Habib (2004), Garach et al (2014), andCamacho-Torregrosa (2015).…”

Section: Comparison With Previous Global Consistency Modelsmentioning

confidence: 99%

“…Selected road segments must be homogeneous because the results depend on its selection (Cafiso et al 2010;Camacho-Torregrosa 2015;Resende and Benekohal 1997). There are three different complementary criteria to determine them:…”

Section: Introductionmentioning

confidence: 99%

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New Consistency Model Based on Inertial Operating Speed Profiles for Road Safety Evaluation

Llopis-Castelló¹,

Bella²,

Torregrosa³

et al. 2018

J. Transp. Eng., Part A: Systems

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Road crashes are mainly caused by three concurrent factors: infrastructure, vehicles, and human factors. The interaction between infrastructure and human factors leads to the concept of geometric design consistency, which can be defined as how drivers' expectations and road behavior fit. This paper presents a new global consistency model based on the difference between the inertial operating speed profile (V i ) and the operating speed profile (V 85 ). The first is calculated as the weighted average speed of the previous road section and represents drivers' expectations, whereas the second represents road behavior. A set of 71 homogeneous two-lane rural road segments located in Italy were used in the calibration of the model. As a result, a safety performance function based on this new consistency model was proposed to estimate the number of crashes on an entire road segment. Finally, the new model was compared with previous global consistency models, concluding that the new consistency parameter better explains the phenomenon than the previous ones. Therefore, the new consistency model is a useful tool for engineers that allows estimation of the number of crashes and incorporates road safety into the geometric design of both new two-lane rural roads and improvements to existing highways.

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Section: Discussionmentioning

confidence: 99%

“…The new consistency model has been compared with the global consistency models developed by Polus and Mattar-Habib (2004), Garach et al (2014), andCamacho-Torregrosa (2015).…”

Section: Comparison With Previous Global Consistency Modelsmentioning

confidence: 99%

See 1 more Smart Citation

New Consistency Model Based on Inertial Operating Speed Profiles for Road Safety Evaluation

Llopis-Castelló¹,

Bella²,

Torregrosa³

et al. 2018

J. Transp. Eng., Part A: Systems

View full text Add to dashboard Cite

show abstract

“…Finally, Camacho-Torregrosa ( 8 ) developed another global consistency model considering two operational parameters: the average operating speed and the average deceleration rate. In addition, this study highlights the importance of using homogeneous road segments.…”

mentioning

confidence: 99%

“…Furthermore, the selection of the road is critical for the application of global consistency models. The road segments must be homogeneous, since the length along which the a priori expectancies of drivers are acquired plays a major role ( 8 , 13 , 18 ).…”

mentioning

confidence: 99%

Time-Based Calibration of the Inertial Operating Speed to Enhance the Assessment of the Geometric Design Consistency

Llopis-Castelló

Bella

Torregrosa

et al. 2018

Transportation Research Record: Journal of the Transportation R

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Road crashes are mainly caused by three concurrent factors: infrastructure, vehicle, and human factors. The interaction between the infrastructure and human factors leads to the concept of geometric design consistency. Recently, a global consistency model was developed based on the difference between the inertial operating speed profile and the operating speed profile. The first was defined as the weighted average operating speed of the previous road section based on distance, and represents drivers’ expectancies, whereas the second represents road behavior. However, drivers’ expectancies are related to short-term memory which declines gradually and depends on time. Thus, a time-based inertial operating speed would allow a more accurate estimation of the phenomenon. This research analyzes different periods of time and weighting distributions to identify how drivers’ expectancies should be estimated. A set of 71 homogeneous road segments located in Italy were considered in the study. As a result, 25 seconds and a convex parabolic distribution should be used to calculate the inertial operating speed profile. This new way of estimating drivers’ expectancies showed better results than those obtained based on distance. Finally, the proposed consistency model was compared with the previous models and was found to be able to assess more accurately the geometric design consistency. Therefore, the proposed consistency model is a useful tool for engineers to estimate the number of crashes so that they can incorporate road safety considerations into the geometric design of either new two-lane rural roads, or improving the existing ones.

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Comparison of the highway safety manual predictive method with safety performance functions based on geometric design consistency

Llopis-Castelló

Findley

García

2020

Journal of Transportation Safety & Security

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Road safety is a major public health concern in our society. Effective road design and accurate safety analyses must be a component of programs focused on reducing and eliminating roadway injuries and deaths. Various methodologies exist to determine the expected number of crashes on rural two-lane rural roads. This research compares different procedures which allow for the estimation of the number of crashes on homogeneous road segments. In this effort, a total of 27 two-lane rural road sections located in North Carolina were considered, resulting in 59 homogeneous road segments composed of 350 horizontal curves and 375 tangents along 150 km of road. Four methods were applied to the selected roadways: the HSM predictive method, two jurisdiction-specific Safety Performance Functions (SPFs), and a SPF which includes a consistency parameter. This research found that the use of SPFs which incorporate a consistency parameter allows highway engineers to consider human factor impacts on road safety assessment. The use of a consistency parameter can also simplify the crash estimation process. Analysis methods which only included local geometric variables provided unreliable results due to the calibration of only the specific road elements instead of their relationship with other road elements along homogeneous road segments.

show abstract

Development and Calibration of a Global Geometric Design Consistency Model for Two-Lane Rural Highways, Based on the Use of Continuous Operating Speed Profiles

Cited by 4 publications

References 43 publications

New Consistency Model Based on Inertial Operating Speed Profiles for Road Safety Evaluation

New Consistency Model Based on Inertial Operating Speed Profiles for Road Safety Evaluation

Time-Based Calibration of the Inertial Operating Speed to Enhance the Assessment of the Geometric Design Consistency

Comparison of the highway safety manual predictive method with safety performance functions based on geometric design consistency

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