Investigating the relationship between run-off-the-road crash frequency and traffic flow through different functional forms

This paper discusses the issue of statistical analysis of traffic flow in different regions of Poland. Such analysis allows us to identify “valuable (sensitive) areas” whose damage or blockage may provoke considerable disturbances or even a stoppage of traffic flow in the examined road network. The results of the studies indicate that the road network in Poland has the properties of a scale-free network. The distribution of the examined variables does not have a normal character, whereas the relationship between the number of nodes and the number of connections is a power-law feature.

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Safety Effects of Horizontal Curve Reliability Index

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198120930715 ◽

2020 ◽

Vol 2674 (9) ◽

pp. 627-636

Author(s):

Scott Himes ◽

Eric Donnell

Keyword(s):

Reliability Index ◽

Horizontal Curve ◽

Mass Model ◽

Crash Frequency ◽

Horizontal Curves ◽

Run Off ◽

Single Vehicle ◽

Green Book ◽

Total Curve ◽

The Relationship

Recent advancements in analytical processes have used probabilistic approaches to examine the efficacy of the point mass model (and other Green Book models) to develop reliability-based approaches for geometric design. However, there has been minimal research establishing the link between reliability measures and substantive safety (expressed through crash frequency). The objective of this paper is to use empirical data supporting the calculation of reliability index for existing horizontal curves and to estimate the relationship between reliability index and crash frequency. Other horizontal curve-related characteristics that may have an impact on crash frequency on horizontal curves for rural two-lane highways and rural freeway facilities are controlled for in the evaluation. The safety analysis showed that the wet pavement reliability index was significantly associated with crash frequency for total curve-related crashes, single-vehicle run-off-road crashes, rollover crashes, truck-related crashes, and weather-related crashes. The relationship was strongest for the reliability index in its continuous form, meaning that the effect is continuous across the range of wet pavement reliability that was observed.

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Research on Closed Residential Area Based on Balanced Distribution Theory

E3S Web of Conferences ◽

10.1051/e3sconf/20183803001 ◽

2018 ◽

Vol 38 ◽

pp. 03001

Author(s):

Si Lan ◽

Ni Fang ◽

Hai Peng Lin ◽

Shi Qi Ye

Keyword(s):

Traffic Flow ◽

Residential Area ◽

Distribution Model ◽

The Road ◽

Resistance Model ◽

Balanced Distribution ◽

Residential Quarters ◽

Opening And Closing ◽

The Impact ◽

The Relationship

With the promotion of the street system, residential quarters and units of the compound gradually open. In this paper, the relationship between traffic flow and traffic flow is established for external roads, and the road resistance model is established by internal roads. We propose a balanced distribution model from the two aspects of road opening conditions and traffic flow inside and outside the district, and quantitatively analyze the impact of the opening and closing on the surrounding roads. Finally, it puts forward feasible suggestions to improve the traffic situation and optimize the network structure.

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Impact of Congestion and Traffic Flow on Crash Frequency and Severity: Application of Smartphone-Collected GPS Travel Data

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/2659-05 ◽

2017 ◽

Vol 2659 (1) ◽

pp. 43-54 ◽

Cited By ~ 8

Author(s):

Joshua Stipancic ◽

Luis Miranda-Moreno ◽

Nicolas Saunier

Keyword(s):

Traffic Flow ◽

Traffic Congestion ◽

Quebec City ◽

Crash Severity ◽

Crash Frequency ◽

Crash Data ◽

Instrumented Vehicles ◽

Minor Injuries ◽

The Impact ◽

The Relationship

Mobility and safety are the two greatest priorities within any transportation system. Ideally, traffic flow enhancement and crash reductions could occur simultaneously, although their relationship is likely complex. The impact of traffic congestion and flow on road safety requires more empirical evidence to determine the direction and magnitude of the relationship. The study of this relationship is an ideal application for instrumented vehicles and surrogate safety measures (SSMs). The purpose of this paper is to correlate quantitative measures of congestion and flow derived from smartphone-collected GPS data with collision frequency and severity at the network scale. GPS travel data were collected in Quebec City, Quebec, Canada, and the sample for this study contained data for more than 4,000 drivers and 20,000 trips. The extracted SSMs, the congestion index (CI), average speed ( V), and the coefficient of variation of speed (CVS) were compared with crash data collected over an 11-year period from 2000 to 2010 with the use of Spearman’s correlation coefficient and pairwise Kolmogorov–Smirnov tests. The correlations with crash frequency were weak to moderate. CI was shown to be positively correlated with crash frequency, and the relationship to crash severity was found to be nonmonotonous. Higher congestion levels were related to crashes with major injuries, whereas low congestion levels were related to crashes with minor injuries and fatalities. Surprisingly, V was found to be negatively correlated with crash frequency and had no conclusive statistical relationship to crash severity. CVS was positively correlated with crash frequency and statistically related to increased crash severity. Future work will focus on the development of a network screening model that incorporates these SSMs.

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Hubungan Volume, Kecepatan Dan Kepadatan Dengan Model Greenshields, Greenberg, Dan Underwood Pada Ruas Jalan Luar Kota Kawasan Gunung Geurutee

Jurnal Arsip Rekayasa Sipil dan Perencanaan ◽

10.24815/jarsp.v2i4.14945 ◽

2019 ◽

Vol 2 (4) ◽

pp. 286-293

Author(s):

Ari Juanda ◽

Muhammad Isya ◽

Noer Fadhly

Keyword(s):

Traffic Flow ◽

Model Equation ◽

Volume Density ◽

Coefficient Of Determination ◽

Mountainous Area ◽

The Road ◽

Traffic Conditions ◽

Relationship Of ◽

The Relationship ◽

The City

In Indonesia, Karl-L Bang research in 1994 on the relationship between traffic parameters was included in the Indonesian Road Capacity Manual 1997. The research has undergone many changes between 1994 and 2018 in the growth of traffic that may affect traffic flow and volume, speed and density all urban roads, roads outside the city in an area, In Aceh studies have also been conducted into the relationship between traffic parameters on different roads. On this basis, it is very necessary to know the characteristics of traffic flows that occur on the Banda Aceh - Meulaboh section 65 + 450 is located in Aceh Jaya Regency, in the province of Aceh. Given that this road is located in an extremely mountainous area, where there are many very steep curves and ravines and rocks on the cliff side of the road. Analysis using models Greenshields, Greenberg, and Underwood. The results of the study show that the Greenshields model is the most satisfying compared to the Greenberg model and the Underwood model with a coefficient of determination (R2) greater than 0.88. The model is in accordance with the traffic conditions on the Outer City Road. Then the traffic flow obtained can not reach optimum conditions, namely in a stable traffic flow condition. The relationship between speed and density (S-D) with the model equation is S = 36,525 - 0,815 D; The volume-density (V-D) relationship with the model equation is V = 36,525 D - 0,815 D2; The relationship of volume - speed (V-S) with the model equation is V = 44,835 S - 1,228 S2

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Analisis Kecepatan Rata-Rata Lalu Lintas Di Ruas Jalan Pilau Akibat Kendaraan Berbelok

Media Ilmiah Teknik Sipil ◽

10.33084/mits.v9i2.2324 ◽

2021 ◽

Vol 9 (2) ◽

pp. 129-136

Author(s):

Nirwana Puspasari

Keyword(s):

Traffic Flow ◽

Primary Data ◽

The Road ◽

Smooth Flow ◽

Road Section ◽

A Value ◽

Traffic Data Collection ◽

Average Travel Time ◽

On The Road ◽

The Relationship

Often we encounter several obstacles that cause traffic concentration at several points on a road segment which causes traffic movement to slow down and even stop. Concentration of traffic flow occurs at intersection points, such as one at the Pilau-Keruing intersection, where traffic moving on the Pilau road is forced to slow down when the traffic flow from Keruing road turns right to cut the flow. Therefore, it is very important to know the effect of turning movement on the smooth flow of traffic. Data collection was carried out by sending several surveyors to the field to obtain secondary and primary data. Furthermore, the analysis of road performance using the 1997 Indonesian Road Capacity Manual. The average space speed obtained from the graph of the relationship between DS and vlv is vlv=28 km/hour. The average speed from the results of the speed survey on the road section gives a value of vlv = 29.6 km / h with conditions without any obstacles to the flow of turning from the Keruing road to the Pilau road, and vlv = 25.6 km / h with the presence of turning current obstacles . There was a decrease in average travel time of 5.9 seconds, with a decrease in traffic speed of 4 km/hour due to the influence of vehicles turning from Keruing road to Jati road.

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Observations on the Relationship between Crash Frequency and Traffic Flow

Safety ◽

10.3390/safety7010003 ◽

2021 ◽

Vol 7 (1) ◽

pp. 3

Author(s):

Peter Wagner ◽

Ragna Hoffmann ◽

Andreas Leich

Keyword(s):

Traffic Flow ◽

Negative Binomial Distribution ◽

Negative Binomial ◽

Data Display ◽

Crash Frequency ◽

Crash Rates ◽

Traffic State ◽

Order Polynomial ◽

The Relationship ◽

The City

This work analyzes the relationship between crash frequency N (crashes per hour) and exposure Q (cars per hour) on the macroscopic level of a whole city. As exposure, the traffic flow is used here. Therefore, it analyzes a large crash database of the city of Berlin, Germany, together with a novel traffic flow database. Both data display a strong weekly pattern, and, if taken together, show that the relationship N(Q) is not a linear one. When Q is small, N grows like a second-order polynomial, while at large Q there is a tendency towards saturation, leading to an S-shaped relationship. Although visible in all data from all crashes, the data for the severe crashes display a less prominent saturation. As a by-product, the analysis performed here also demonstrates that the crash frequencies follow a negative binomial distribution, where both parameters of the distribution depend on the hour of the week, and, presumably, on the traffic state in this hour. The work presented in this paper aims at giving the reader a better understanding on how crash rates depend on exposure.

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Evaluating the Safety Risk of Rural Roadsides Using a Bayesian Network Method

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16071166 ◽

2019 ◽

Vol 16 (7) ◽

pp. 1166 ◽

Cited By ~ 3

Author(s):

Tianpei Tang ◽

Senlai Zhu ◽

Yuntao Guo ◽

Xizhao Zhou ◽

Yang Cao

Keyword(s):

Bayesian Network ◽

Low Cost ◽

Road Networks ◽

Access Point ◽

Safety Risk ◽

Crash Data ◽

Risk Levels ◽

The Road ◽

Run Off ◽

Point Density

Evaluating the safety risk of rural roadsides is critical for achieving reasonable allocation of a limited budget and avoiding excessive installation of safety facilities. To assess the safety risk of rural roadsides when the crash data are unavailable or missing, this study proposed a Bayesian Network (BN) method that uses the experts’ judgments on the conditional probability of different safety risk factors to evaluate the safety risk of rural roadsides. Eight factors were considered, including seven factors identified in the literature and a new factor named access point density. To validate the effectiveness of the proposed method, a case study was conducted using 19.42 km long road networks in the rural area of Nantong, China. By comparing the results of the proposed method and run-off-road (ROR) crash data from 2015–2016 in the study area, the road segments with higher safety risk levels identified by the proposed method were found to be statistically significantly correlated with higher crash severity based on the crash data. In addition, by comparing the respective results evaluated by eight factors and seven factors (a new factor removed), we also found that access point density significantly contributed to the safety risk of rural roadsides. These results show that the proposed method can be considered as a low-cost solution to evaluating the safety risk of rural roadsides with relatively high accuracy, especially for areas with large rural road networks and incomplete ROR crash data due to budget limitation, human errors, negligence, or inconsistent crash recordings.

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The Road More Travelled: The Differential Effects of Spatial Experience in Young and Elderly Participants

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18020709 ◽

2021 ◽

Vol 18 (2) ◽

pp. 709

Author(s):

Antonella Lopez ◽

Alessandro Germani ◽

Luigi Tinella ◽

Alessandro Oronzo Caffò ◽

Albert Postma ◽

...

Keyword(s):

Mental Representations ◽

Spatial Relations ◽

The Elderly ◽

The Road ◽

Socio Demographic Factors ◽

Effects Of Aging ◽

Coordinate Spatial Relations ◽

Categorical Spatial Relations ◽

The Relationship

Our spatial mental representations allow us to give refined descriptions of the environment in terms of the relative locations and distances between objects and landmarks. In this study, we investigated the effects of familiarity with the everyday environment, in terms of frequency of exploration and mode of transportation, on categorical and coordinate spatial relations, on young and elderly participants, controlling for socio-demographic factors. Participants were tested with a general anamnesis, a neuropsychological assessment, measures of explorations and the Landmark Positioning on a Map task. The results showed: (a) a modest difference in performance with categorical spatial relations; (b) a larger difference in coordinate spatial relations; (c) a significant moderating effect of age on the relationship between familiarity and spatial relations, with a stronger relation among the elderly than the young. Ceteris paribus, the role of direct experience with exploring their hometown on spatial mental representations appeared to be more important in the elderly than in the young. This advantage appears to make the elderly wiser and likely protects them from the detrimental effects of aging on spatial mental representations.

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Fail to Yield? An Analysis of Ambulance Crashes in Taiwan

Sustainability ◽

10.3390/su13031566 ◽

2021 ◽

Vol 13 (3) ◽

pp. 1566

Author(s):

Rong-Chang Jou ◽

Ming-Che Chao

Keyword(s):

Public Education ◽

Weather Conditions ◽

Medical Emergency ◽

Transportation Safety ◽

Emergency Vehicle ◽

The Road ◽

Mnl Model ◽

On The Road ◽

Crash Injuries ◽

The Relationship

Introduction—Medical emergency vehicles help patients get to the hospital quickly. However, there were more and more ambulance crashes on the road in Taiwan during the last decade. This study investigated the characteristics of medical emergency vehicle crashes in Taiwan from January 2003 to December 2016. Methods—The ordered logit (OL) model, multinominal logit (MNL) model, and partial proportional odds (PPO) model were applied to investigate the relationship between the severity of ambulance crash injuries and its risk factors. Results—We found the various factors have different effects on the overall severity of ambulance crashes, such as ambulance drivers’ characteristics and road and weather conditions. When another car was involved in ambulance crashes, there was a disproportionate effect on the different overall severity, as found by the PPO model. Conclusions—The results showed that male ambulance drivers and car drivers who failed to yield to an ambulance had a higher risk of severe injury from ambulance crashes. Ambulance crashes are an emerging issue and need further policies and public education regarding Taiwan’s ambulance transportation safety.

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