scholarly journals Evaluation of the Use of a Road Diet Design: An Urban Corridor Case Study in Washington, DC

2021 ◽  
Vol 13 (16) ◽  
pp. 8964
Author(s):  
Mohammad A. Aljamal ◽  
Derek Voight ◽  
Jacob Green ◽  
Jianwei Wang ◽  
Huthaifa I. Ashqar
Keyword(s):  
Empirical Bayes ◽  
Annual Number ◽  
Full Time ◽  
Left Turn ◽  
The Road ◽  
Traffic Calming ◽  
Before And After ◽  
Traffic Volumes ◽  
Bayes Analysis ◽  
Urban Corridor

A traditional road diet design converts a four-lane two-way road to a three-lane road consisting of two through lanes and a center two-way left turn lane. This paper introduces a new application of the road diet design in an urban corridor. Specifically, the new application converts a four-lane two-way road into a two-lane two-way road with full-time parking lanes in both directions. The paper analyzed the traffic impacts of the road diet application on the corridor of New Jersey Avenue, northwest, in the city of Washington, District of Columbia. The corridor included five signalized and one unsignalized intersections. Before-and-after analyses using Synchro 11 simulation and Site-Specific Empirical Bayes analysis were used to evaluate and compare existing and proposed scenarios. The proposed scenario provided various benefits including offering accessibility to the businesses in the area and acting as a traffic calming strategy. For signalized intersections, the overall performance remained the same for most intersections except for one intersection (on P Street), as it is significantly impacted by the road diet design due to the dramatic increase of traffic volumes in its minor streets as a result of diverting traffic volumes from the unsignalized intersection for left and through movements. Results showed that the use of a road diet design enhanced the unsignalized intersection performance due to the traffic volume divergence from its minor streets and enhanced the safety of the study area by decreasing the annual number of predicted crashes. To achieve better operational benefits and reflect traffic demands, the paper recommends to re-optimize signal timings when a road diet design is adopted.

scholarly journals Identification of the Determinants of the Effectiveness of On-Road Chicanes in the Village Transition Zones Subject to a 50 km/h Speed Limit

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4002
Author(s):  
Alicja Barbara Sołowczuk ◽  
Dominik Kacprzak
Keyword(s):  
Traffic Management ◽  
Road Traffic ◽  
Speed Reduction ◽  
Factors Affecting ◽  
Transition Zones ◽  
The Road ◽  
Traffic Calming ◽  
Before And After ◽  
Traffic Volumes ◽  
The Village

In recent years, in which a considerable increase in the road traffic volumes has been witnessed, traffic calming has become one the key issues in the area of road engineering. This concerns, in particular, trunk roads passing through small villages with a population of up to 500 and the road section length within the village limits of ca. 1400–1700 m. A successful traffic calming scheme must involve primarily effective reduction in inbound traffic speed. A review of the data from various countries revealed that chicanes installed in the transition zones may have a determining effect on the success of the traffic calming project. The effectiveness of such chicanes depends mainly on the type of chicane, its location on the carriageway, its shape and the size of the lateral deflection imposed by the chicane on the inbound lane. The purpose of this study was to identify the speed reduction determinants in traffic calming schemes in village transition zones, based on a central island horizontally deflecting one lane of a two-lane two-way road with 50 km/h speed restriction. As part of the study, vehicle speeds were measured just before and after the chicanes under analysis. Furthermore, the inbound lane traffic volumes were measured in field and a number of factors were identified, including the applied traffic management scheme, road parameters, view of the road ahead and of the village skyline, isolated buildings, road infrastructure and adjacent roadside developments. The obtained data were analysed with a method employing tautologies of the selected 32 factors affecting the drivers’ perception. A single aggregate parameter was proposed for assessing the coincidence of the influence of selected factors on speed reduction. The analysis of the existing schemes and the results of statistical analyses carried out in this study confirmed the authors’ hypothesis that the combined selected factors produce a desirable effect and that they should be additionally enhanced by the application of solar powered devices.

scholarly journals Measurements of urban traffic parameters before and after road reconstruction

2021 ◽  
Vol 11 (1) ◽  
pp. 365-376
Author(s):  
Andrzej Bąkowski ◽  
Leszek Radziszewski
Keyword(s):  
Urban Traffic ◽  
Noise Model ◽  
Vehicle Traffic ◽  
The Road ◽  
Passenger Vehicles ◽  
Before And After ◽  
Traffic Volumes ◽  
National Road ◽  
The City ◽  
Good Agreement

Abstract The study analyzed the parameters of vehicle traffic and noise on the national road in the section in the city from 2011 to 2016. In 2013–2014 this road was reconstructed. It was found that in most cases, the distribution of the tested variable was not normal. The median and selected percentiles of vehicle traffic parameters and noise were examined. The variability and type A uncertainty of the results were described and evaluated. The results obtained for the data recorded on working and non-working days were compared. The vehicle cumulative speed distributions, for two-way four-lane road segments in both directions were analyzed. A mathematical model of normalized traffic flow has been proposed. Fit factor R2 of the proposed equations to the experimental data for passenger vehicles ranges from 0.93 to 0.99. It has been shown that two years after the road reconstruction, the median noise level did not increase even though traffic volumes and vehicle speeds increased. The Cnossos noise model was validated for data recorded over a period of 6 years. A very good agreement of the medians determined according to the Cnossos-EU model and the measured ones was obtained. It should be noted, however, that for the other analyzed percentiles, e.g. 95%, the discrepancies are larger.

scholarly journals Identification of Determinants of the Speed-Reducing Effect of Pedestrian Refuges in Villages Located on a Chosen Regional Road

Symmetry ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 597
Author(s):  
Alicja Sołowczuk ◽  
Dominik Kacprzak
Keyword(s):  
Traffic Engineering ◽  
Geometric Parameters ◽  
Speed Reduction ◽  
The Road ◽  
Traffic Calming ◽  
Engineering Discipline ◽  
Number Of Factors ◽  
Before And After ◽  
Layout Geometry ◽  
Specific Factors

Traffic calming, as a traffic engineering discipline, is becoming an increasingly important aspect of the road engineering process. One of the traffic calming treatments are pedestrian refuges—raised islands located on or at the road centreline. This paper presents factors relevant to the performance of this kind of traffic calming devices retrofitted on the stretches of regional roads in village areas. To this end, speed surveys were carried out before and after the islands in each direction on purposefully chosen test sections. In order to identify the determinants, each test section was characterised by features including the symmetry of the road layout geometry, surrounding features and the existing traffic signs and, last but not least, visibility of the road ahead. The survey data were used by the authors to perform analyses in order to group the speeds at the pedestrian refuges and relate them to specific factors and, finally, identify the determinants of speed reduction. In this way, the authors arrived at a conclusion that the performance of pedestrian refuges depends on a number of factors rather than solely on their geometric parameters. The analyses showed that the pedestrian refuge geometric parameters, features located in its proximity that influence the driver’s perception and placement of appropriate marking, can, in combination, result in achieving the desired speed reduction and ensure safety of non-motorised users. These hypotheses were tested on a stretch of a regional road in village area at three points of the process: before upgrading, after installation of pedestrian refuges, and after retrofitting of enhancements.

scholarly journals Developing a Clustering-Based Empirical Bayes Analysis Method for Hotspot Identification

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Yajie Zou ◽  
Xinzhi Zhong ◽  
John Ash ◽  
Ziqiang Zeng ◽  
Yinhai Wang ◽  
...  
Keyword(s):  
Empirical Bayes ◽  
Reference Group ◽  
Analysis Method ◽  
Crash Frequency ◽  
Crash Data ◽  
The Road ◽  
Safety Performance Functions ◽  
Bayes Analysis ◽  
Rural Highway ◽  
Selection Of

Hotspot identification (HSID) is a critical part of network-wide safety evaluations. Typical methods for ranking sites are often rooted in using the Empirical Bayes (EB) method to estimate safety from both observed crash records and predicted crash frequency based on similar sites. The performance of the EB method is highly related to the selection of a reference group of sites (i.e., roadway segments or intersections) similar to the target site from which safety performance functions (SPF) used to predict crash frequency will be developed. As crash data often contain underlying heterogeneity that, in essence, can make them appear to be generated from distinct subpopulations, methods are needed to select similar sites in a principled manner. To overcome this possible heterogeneity problem, EB-based HSID methods that use common clustering methodologies (e.g., mixture models, K-means, and hierarchical clustering) to select “similar” sites for building SPFs are developed. Performance of the clustering-based EB methods is then compared using real crash data. Here, HSID results, when computed on Texas undivided rural highway cash data, suggest that all three clustering-based EB analysis methods are preferred over the conventional statistical methods. Thus, properly classifying the road segments for heterogeneous crash data can further improve HSID accuracy.

Estimated Construction Period Impact of Widening State Highway 21 in Caldwell, Texas

1996 ◽  
Vol 1559 (1) ◽  
pp. 76-83
Author(s):  
Marie T. Wildenthal ◽  
Jesse L. Buffington
Keyword(s):  
Property Values ◽  
Land Values ◽  
Cost Ratio ◽  
Full Time ◽  
Business Managers ◽  
Left Turn ◽  
Benefit Cost Ratio ◽  
State Highway ◽  
Traffic Volumes ◽  
The Impact

Documented are the during- and after-construction effects of widening a highway. Between 1991 and 1993, a 3.75 km (2.33 mi) section of State Highway (TX-21) in Caldwell, Texas, a town of 3,000, was widened for a continuous two-way left-turn lane with curbs and gutters. Data collected during and after construction include information about the abutting businesses' estimation of the impact of construction on their businesses profits and property values and on the traffic volumes, travel times, and accident rates of the highway. The number of most businesses' usable parking spaces, customers per day, and full-time and part-time employees decreased slightly during construction. Most business managers thought that sales decreased. Reported sales figures showed a 5 percent decrease, which was less severe than the business managers had estimated. Appraised abutting property values fell between 1990 and 1992, while land values increased. Construction expenditures in Texas totaled $6.095 million. The Texas input-output model estimates the impact of these expenditures to be $22.5 million in additional output and 364 jobs for the statewide economy, including $7.5 million in additional output and 121 jobs for the Caldwell economy. The benefit-cost ratio was 1.71—that is, the motorists are receiving $1.71 in benefits for every dollar spent on the project.

scholarly journals Safety Effectiveness of Intersection Left- and Right-Turn Lanes

2003 ◽  
Vol 1840 (1) ◽  
pp. 131-139 ◽  
Author(s):  
Douglas W. Harwood ◽  
Karin M. Bauer ◽  
Ingrid B. Potts ◽  
Darren J. Torbic ◽  
Karen R. Richard ◽  
...  
Keyword(s):  
Traffic Control ◽  
Empirical Bayes ◽  
Matched Pair ◽  
Left Turn ◽  
Before And After ◽  
Accident Data ◽  
Left And Right ◽  
Safety Effectiveness ◽  
Evaluation Approaches ◽  
Control Traffic

The results of research involving a well-designed before-and-after evaluation of the safety effects of providing left- and right-turn lanes for at-grade intersections are presented. Geometric design, traffic control, traffic volume, and traffic accident data were gathered for a total of 280 improved intersections as well as 300 similar intersections that were not improved during the study period. The types of improvement projects evaluated included installation of added left-turn lanes, added right-turn lanes, and extension of the length of existing left- or right-turn lanes. An observational before-and-after evaluation of these projects was performed by using several alternative evaluation approaches. Three contrasting approaches to before-and-after evaluation were used: the yoked comparison or matched-pair approach, the comparison group approach, and the empirical Bayes approach. The research not only evaluated the safety effectiveness of left- and right-turn lane improvements but also compared the performances of these three alternative approaches in making such evaluations. The research developed quantitative safety effectiveness measures for installation design improvements involving added left-turn lanes and added right-turn lanes. The research concluded that the empirical Bayes method provides the most accurate and reliable results. Further use of this method is recommended.

Safety Performance of Flashing Yellow Arrow for Protected–Permissive Left-Turn Signal Control in Central Illinois

2017 ◽  
Vol 2636 (1) ◽  
pp. 32-42 ◽  
Author(s):  
Kerrie L. Schattler ◽  
Eric P. Anderson ◽  
Trevor Hanson
Keyword(s):  
Empirical Bayes ◽  
Safety Evaluation ◽  
Left Turn ◽  
Turn Signal ◽  
Crash Data ◽  
Flashing Yellow Arrow ◽  
Before And After ◽  
Control Research ◽  
Central Illinois ◽  
Yellow Arrow

In 2010, the Illinois Department of Transportation began implementing the flashing yellow arrow (FYA) at intersections operating with protected–permissive left-turn (PPLT) control. Research was conducted to evaluate the safety-effectiveness of FYAs at 86 intersections and 164 approaches in central Illinois. The effectiveness evaluation was performed with 3 years of before-and-after FYA installation crash data and the empirical Bayes method. In the before condition, the left-turn signals operated with a circular green display indicating the permissive interval of PPLT control using a five-section signal head. In the after condition, the FYA replaced the circular green display for the permissive interval of PPLT with a four-section signal head. Supplemental traffic signs were mounted on the mast arm adjacent to the left-turn signal at over half of the FYA installations. The results of the comprehensive safety evaluation of the FYA for PPLT control are presented. Analyses were also performed to assess the effects of the FYA supplemental signs and the effects of the FYA overall on two subsets of at-fault drivers: older drivers (age 65+) and younger drivers (age 16 to 21). The resulting mean crash modification factors for the targeted crash types ranged from 0.589 to 0.714. The findings of this research support the continued use of FYAs for PPLT control to improve safety at signalized intersections in central Illinois.

Before-and-After Empirical Bayes Evaluation of Achieving Bare Pavement using Anti-Icing on Urban Roads

2020 ◽  
Vol 2674 (2) ◽  
pp. 92-101
Author(s):  
Maged Gouda ◽  
Karim El-Basyouny
Keyword(s):  
Empirical Bayes ◽  
Cost Savings ◽  
Road Maintenance ◽  
The Road ◽  
Before And After ◽  
Deicing Chemicals ◽  
Winter Road ◽  
Nonfatal Injury ◽  
Ice Control ◽  
Snow And Ice

Canadian municipalities are increasingly choosing to achieve bare pavement (BP) for snow and ice control during fall/winter seasons. When a snowstorm event is forecasted, one strategy is to apply anti-icing chemicals to the pavement surface to prevent the snow and ice from forming a bond with the road surface. Such an approach facilitates a more efficient plowing operation and reduces the amount of deicing chemicals needed to achieve BP. This study assesses the safety performance of achieving BP using anti-icing compared with the traditional reactive winter road maintenance (WRM) approach on urban roads using the before-and-after Empirical Bayes technique. Results suggest that achieving BP significantly reduces all collision types and severities on midblocks with a reduction value in the range of 13.7% to 19.7%. Attaining BP at intersections was found to be very effective in reducing injury collisions with an estimated reduction of 12.5%. When sites were grouped based on a WRM priority-basis, it was found that anti-icing was effective for reducing the majority of collision types and severities at the different priority levels with reductions ranging from 8.7% to 49.83% on midblocks and between 5.37% and 13% at intersections. All reductions were statistically significant. The monetary benefits of the reductions in property-damage only and nonfatal injury collisions were estimated at 60 million Canadian dollars using a 1.92% interest rate and a 2-year service life. These findings provide unequivocal evidence that achieving BP using anti-icing can lead to significant societal safety benefits that economically translate to huge collision cost savings.

scholarly journals Observational Before and After Safety Study of Installing Signals at Rural Intersections: Using the Empirical Bayes (EB) and Conventional Methods

2021 ◽  
Author(s):  
Ravindranauth Bhim
Keyword(s):  
Economic Benefit ◽  
Empirical Bayes ◽  
Signal Control ◽  
Percent Reduction ◽  
Safety Study ◽  
Left Turn ◽  
Before And After ◽  
Conventional Methods ◽  
Safety Effect ◽  
Crash Types

Signalizing an intersection usually results in a reduction in right-angle and left-turn crashes, and an increase in rear-end crashes. This study used the conventional and Empirical Bayes (EB) before and after methods on 45 treated sites (converted from stop to signal control) in California and Minnesota to estimate the safety effect of having signals installed. The results confirm the belief that right-angle and left-turn crashes are reduced and rear-end crashes increase. However, these effects cannot be used to quantitatively assess the benefit gained from the reduction in right-angle and left-turn crashes against the increase in rear-end crashes, simply because crash types have different severities. By performing an economic examination of the safety effects, this study was able to show that by installing signals on 45 treated sites, there was a positive aggregate economic benefit of $155,883,978 which represents a 69 percent reduction in cost. This translated into $616,142 per site-year.

scholarly journals Evolution of the Road and Rail Transport of Goods in European Countries before and after the Financial Crises

2019 ◽  
Vol 21 (4) ◽  
pp. 3-12
Author(s):  
Antonio Danesi ◽  
Davide Ongari ◽  
Cristian Poliziani ◽  
Federico Rupi
Keyword(s):  
Financial Crises ◽  
Rail Transport ◽  
European Countries ◽  
The Road ◽  
The United Kingdom ◽  
Freight Traffic ◽  
Before And After ◽  
Traffic Volumes ◽  
Strong Relation ◽  
Recent Trends

The main goal of this paper is to analyse recent trends in freight transport volumes as well as their relation to socio-economic and infrastructural variables, in the case of the following major European countries: France, Germany, Italy, Poland, Spain and the United Kingdom. This analysis refers to the period 2005-2016, so that years affected by the global economic crisis, which shows its peak in 2009, are taken into account. This research demonstrated that not all the countries under study show a strong relation between freight traffic and GDP as it could have been expected based on well consolidated experiences and studies. Moreover, other relations are investigated, with mixed results, between the freight traffic volumes and the extension of the rail and road networks as well as oil price data.

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