One-way Streets Research Articles

The Modified Rural Postman Problem in Vehicle Route Optimization

The submitted paper deals with designing routes of the vehicles, which provide the transport network services. We limit our focus to such tasks, where the priority is the edge service in the transport network and the initial problem is finding an Eulerian path. Regarding to real-life problems, this contribution presents such procedure of solving, which takes into account both the existence of a mixed transport network containing one-way roads and the existence of a wider transport network. In this network, there are only selected edges with possibility of the effective passages. This problem can be solved by the modified Rural Postman Problem assuming the strongly connected network. Linear programming is a suitable tool for designing optimal routes of service vehicles.

Safety Evaluation for Turnarounds at Diamond Interchanges: Assessing the Texas U-Turn

Texas frontage road turnarounds at diamond interchange locations are a common treatment in the State of Texas. This configuration, also often referred to as the Texas U-turn, allows vehicles traveling on a one-way frontage road to access the opposing direction one-way frontage road via a U-turn before the terminal intersections at the diamond interchange. This technique removes two potential left-turn maneuvers from the adjacent at-grade intersections. The frontage road turnaround has operational benefits that result from shifting vehicles that would typically be occupying the intersection. The safety of these turnaround configurations, however, is not well known. This paper focuses on the observed safety performance of these turnaround configurations at diamond freeway interchanges in Texas. The authors first developed a large randomly sampled data set to facilitate a statistically reliable assessment of U-turn safety performance for Texas interchanges. Next they conducted a safety performance assessment at locations with and without turnarounds and determined that site features that significantly influence the number of crashes include the volume of cross street traffic, the cross street right-turn configuration at frontage roads, the minimum radius in the turnaround, the longitudinal distance from the U-turn exit to the closest downstream driveway, and the number of lanes on each frontage road. The safety performance findings at locations with and without turnarounds suggests that an agency could construct a turnaround to enhance facility operations with the knowledge that construction will not adversely impact safety. Although the research introduced in this paper focuses on Texas locations, the findings should be applicable to similar facilities in other states if the turnaround conditions are similar.

Vehicle actuated signal performance under general traffic at an isolated intersection

We study green extension of a two-phased vehicle actuated signal at an isolated intersection between two one-way streets. The green phase is extended by a preset time interval, referred to as critical gap, from the time of a vehicle actuation at an advance detector. The green phase switches if there is no arrival during the critical gap. We develop an exact model to study the intersection performance with traffic following Poisson processes. We further extend the model to approximate the case of general traffic. Our model in the general case works well compared with Monte Carlo simulation. A few major observations include: (1) The optimal critical gap decreases with the traffic; (2) The optimal critical gap can be much larger (up to 5 s) than the common presumption of 2–3 s; (3) Queue clearance policy is not nearly optimal in general even in the case of heavy traffic.

FGF23 in Cardiovascular Disease: Innocent Bystander or Active Mediator?

Fibroblast growth factor−23 (FGF23) is a mainly osteocytic hormone which increases renal phosphate excretion and reduces calcitriol synthesis. These renal actions are mediated via alpha-klotho as the obligate co-receptor. Beyond these canonical “mineral metabolism” actions, FGF23 has been identified as an independent marker for cardiovascular risk in various patient populations. Previous research has linked elevated FGF23 predominantly to left-ventricular dysfunction and consecutive morbidity and mortality. Moreover, some experimental data suggest FGF23 as a direct and causal stimulator for cardiac hypertrophy via specific myocardial FGF23-receptor activation, independent from alpha-klotho. This hypothesis offers fascinating prospects in terms of therapeutic interventions, specifically in patients with chronic kidney disease (CKD) in whom the FGF23 system is strongly stimulated and in whom left-ventricular dysfunction is a major disease burden. However, novel data challenges the previous stand-alone hypothesis about a one-way road which guides unidirectionally skeletal FGF23 toward cardiotoxic effects. In fact, recent data point toward local myocardial production and release of FGF23 in cases where (acute) myocardial damage occurs. The effects of this local production and the physiological meaning are under current examination. Moreover, epidemiologic studies suggest that high FGF-23 may follow, rather than induce, myocardial disease in certain conditions. In summary, while FGF23 is an interesting link between mineral metabolism and cardiac function underlining the meaning of the bone-heart axis, more research is needed before therapeutic interventions may be considered.

Switching from Reactant to Substrate Engineering in the Selective Synthesis of Graphene Nanoribbons.

The challenge of synthesizing graphene nanoribbons (GNRs) with atomic precision is currently being pursued along a one-way road, based on the synthesis of adequate molecular precursors that react in predefined ways through self-assembly processes. The synthetic options for GNR generation would multiply by adding a new direction to this readily successful approach, especially if both of them can be combined. We show here how GNR synthesis can be guided by an adequately nanotemplated substrate instead of by the traditionally designed reactants. The structural atomic precision, unachievable to date through top-down methods, is preserved by the self-assembly process. This new strategy's proof-of-concept compares experiments using 4,4''-dibromo-para-terphenyl as a molecular precursor on flat Au(111) and stepped Au(322) substrates. As opposed to the former, the periodic steps of the latter drive the selective synthesis of 6 atom-wide armchair GNRs, whose electronic properties have been further characterized in detail by scanning tunneling spectroscopy, angle resolved photoemission, and density functional theory calculations.

The economic impact of one to two-way street conversions: advancing a context-sensitive framework

As many communities across the US convert one-way streets to two-way traffic flow, a growing body of work seeks to understand the implications. While some work indicates that there can be road safety and performance benefits to these conversions, only a small number of papers deal with the economic implications. This paper examines the economic impact of one to two-way street conversions, using six case studies between 2004 and 2011. Researchers analyzed these cases, looking at relative job growth in conversion areas as compared to the local economy on both an aggregate and job sector basis. These data are then compared with relative income growth and an evaluation of qualitative outcomes. The results illustrate that investment streetscape improvements may have benefit particularly for arts and entertainment sectors, but also need to connect to larger economic development and livability strategy.

Determining Optimum Configuration of One-Way and Two-Way Streets Using Shortest Path Travel Costs Based on Results of Traffic Assignment

Determining Optimum Configuration of One-Way and Two-Way Streets Using Shortest Path Travel Costs Based on Results of Traffic Assignment

Impact Analysis of Travel Time Uncertainty on AGV Catch-Up Conflict and the Associated Dynamic Adjustment

In automated logistics systems, travel time uncertainty can severely affect automated guided vehicle (AGV) conflict and path planning. Insight is required into how travel time uncertainty affects catch-up conflict, the main AGV conflict in one-way road networks. Under normal circumstances, the probability formula for catch-up conflict is deduced based on an analysis of AGV catch-up conflict. The vertex, monotonicity, and symmetry of catch-up conflict probabilities are developed, for symmetrical AGV travel time distribution densities. A dynamic adjustment method based on conflict probability for AGVs is designed. The probability features of catch-up conflicts and the performance of the associated dynamic adjustment are simulated and validated for AGVs at an automated container terminal. The simulation results show that the impact analysis of travel time uncertainty on AGV catch-up conflict is correct, and the dynamic adjustment is effective.

Drunk driving in the Czech Republic: Motivation, risk-reducing strategies, and opinions about sanctions

We examined Czech drunk drivers and their opinions and beliefs about drunk driving, strategies to avoid being caught, and their understanding of the associated legal punishments. Two focus groups were conducted with a total of 10 people who had suspended driving licenses and who had experience with driving under the influence of alcohol. The participants incorrectly believed that a small amount of alcohol does not influence their driving behavior. Some of them incorrectly believed that alcohol might be eliminated from the blood by eating, drinking water, using capsules, or having a short sleep. Most of them declared that they drove under the influence of alcohol because they thought that they were not drunk. Only some expressed that they drove under the influence willingly and repeatedly. Drunk driving was usually a weekend activity. They tried to avoid being caught by police by employing defensive strategies, like using side and one-way roads, driving in a traffic jam, traveling during early morning hours, concentrating excessively on their driving, and wearing inconspicuous clothes. They do not have precise knowledge about the legal sanctions for drunk driving. They are most afraid of having their driver's license suspended. They think that the sanctions are not fair, because they are not applied to all people in the same way.

Where do bike lanes work best? A Bayesian spatial model of bicycle lanes and bicycle crashes

US municipalities are increasingly introducing bicycle lanes to promote bicycle use, increase roadway safety and improve public health. The aim of this study was to identify specific locations where bicycle lanes, if created, could most effectively reduce crash rates. Previous research has found that bike lanes reduce crash incidence, but a lack of comprehensive bicycle traffic flow data has limited researchers’ ability to assess relationships at high spatial resolution. We used Bayesian conditional autoregressive logit models to relate the odds that a bicycle injury crash occurred on a street segment in Philadelphia, PA (n = 37,673) between 2011 and 2014 to characteristics of the street and adjacent intersections. Statistical models included interaction terms to address the problem of unknown bicycle traffic flows, and found bicycle lanes were associated with reduced crash odds of 48% in streets segments adjacent to 4-exit intersections, of 40% in streets with one- or two-way stop intersections, and of 43% in high traffic volume streets. Presence of bicycle lanes was not associated with change in crash odds at intersections with less or more than 4 exits, at 4-way stop and signalized intersections, on one-way streets and streets with trolley tracks, and on streets with low-moderate traffic volume. The effectiveness of bicycle lanes appears to depend most on the configuration of the adjacent intersections and on the volume of vehicular traffic. Our approach can be used to predict specific street segments on which the greatest absolute reduction in bicycle crash odds could occur by installing new bicycle lanes.

The relative efficiency of Iranian\u2019s rural traffic police: a three-stage DEA model

BackgroundRoad traffic Injuries (RTIs) as a health problem imposes governments to implement different interventions. Target achievement in this issue required effective and efficient measures. Efficiency evaluation of traffic police as one of the responsible administrators is necessary for resource management. Therefore, this study conducted to measure Iran’s rural traffic police efficiency.MethodsThis was an ecological study. To obtain pure efficiency score, three-stage DEA model was conducted with seven inputs and three output variables. At the first stage, crude efficiency score was measured with BCC-O model. Next, to extract the effects of socioeconomic, demographic, traffic count and road infrastructure as the environmental variables and statistical noise, the Stochastic Frontier Analysis (SFA) model was applied and the output values were modified according to similar environment and statistical noise conditions. Then, the pure efficiency score was measured using modified outputs and BCC-O model.ResultsIn total, the efficiency score of 198 police stations from 24 provinces of 31 provinces were measured. The annual means (standard deviation) of damage, injury and fatal accidents were 247.7 (258.4), 184.9 (176.9), and 28.7 (19.5), respectively. Input averages were 5.9 (3.0) patrol teams, 0.5% (0.2) manpower proportions, 7.5 (2.9) patrol cars, 0.5 (1.3) motorcycles, 77,279.1 (46,794.7) penalties, 90.9 (2.8) cultural and educational activity score, 0.7 (2.4) speed cameras. The SFA model showed non-significant differences between police station performances and the most differences attributed to the environmental and random error. One-way main road, by road, traffic count and the number of household owning motorcycle had significant positive relations with inefficiency score. The length of freeway/highway and literacy rate variables had negative relations, significantly. Pure efficiency score was with mean of 0.95 and SD of 0.09.ConclusionsIran’s traffic police has potential opportunity to reduce RTIs. Adjusting police performance with environmental conditions is necessary. Capability of DEA method in setting quantitative targets for every station induces motivation for managers to reduce RTIs. Repetition of this study is recommended, annually.

Comparative analysis of the performance of One-Way and Two-Way urban road networks

The fact that the number of vehicles is increasing year after year represents a challenge in road traffic management because it is necessary to adjust the road traffic, in order to prevent any incidents, using mostly the same road infrastructure.At this moment one-way road network provides efficient traffic flow for vehicles but it is not ideal for pedestrians. Therefore, a proper solution must be found and applied when and where it is necessary. Replacing one-way road network with two-way road network may be a viable solution especially if in the area is high pedestrian traffic.The paper aims to highlight the influence of both, one-way and two-way urban road networks through an experimental research which was performed by using traffic data collected in the field. Each of the two scenarios analyzed were based on the same traffic data, the same geometrical conditions of the road (lane width, total road segment width, road slopes, total length of the road network) and also the same signaling conditions (signalised intersection or roundabout).The analysis which involves two-way scenario reveals changes in the performance parameters like delay average, stops average, delay stop average and vehicle speed average.Based on the values obtained, it was possible to perform a comparative analysis between the real, one-way, scenario and the theoretical, two-way, scenario.

Computational elastoplastic Limit Analysis of the Paderno d’Adda bridge (Italy, 1889)

The Paderno d’Adda bridge is a historical iron arch bridge built in 1889 for connecting the provinces of Lecco and Bergamo across the Adda river, in northern Italy. The bridge was designed through the so-called Theory of the Ellipse of Elasticity. Its use is two-fold: a railway track lays within the inner deck of its upper continuous beam; automotive traffic runs on top. Today, after 128 years of continuous duty, the viaduct keeps in service, with trains crossing at slow speed and alternated one-way road traffic with no heavy-weight vehicles. Starting from a computational formulation for the elastoplastic Limit Analysis of 3D truss-frame systems, apt to provide the exact limit load multiplier and attached collapse mechanism, the full evolutive piece-wise-linear response of the bridge is derived, for different try-out loading configurations. The structural analysis, wholly original in its computational implementation, aims at outlining a survey on the potential plastic collapse characteristics of the bridge. Results reveal possible structural deficiencies for the upper continuous beam, where main plasticizations appeared. Instead, elements of the piers plasticized only for tests with loading much un-symmetrically located to the crown of the arch and the slender doubly built-in parabolic arch rarely showed some plasticization. This evidences the arch as a robust characteristic beautiful feature of the bridge. Moreover, analyses pointed out that the effect of the normal forces on the elastoplastic response of the bridge shall not be considered as negligible, as instead it may be often considered in the Limit Analysis of frames.

Reduced Perception of Safety for Cyclists on Multi-Lane, One-Way and Two-Way Streets: Opportunities for Behavioral Economics and Design

Many studies have noted that more dense and accessible environments with higher level of service (LOS) tend to encourage higher levels of walking and bicycling activity. That said as streets are increasingly designed to facilitate safe cycling through built environment interventions, little has been done to evaluate perceptions of safety on different typologies, particularly one vs. two-way corridors. Theory would suggest that many frame their commutes based in-part on the perceived safety of the environment, yet little research looks at varying street design and this perception. This study uses a moving camera approach to evaluate the perceived cycling comfort for drivers and cyclists on different roadway designs (multi-lane, one way; two-way, bidirectional street; singe-land one-way). Results show that perceived safety can influence comfort and potentially modal choice—particularly for parents. If parents perceive routes as unsafe they are reticent to allow their children to walk or bike. Furthermore, we show both drivers and cyclists have different perceptions of speed and relative safety of varying street designs; with those in a driving role perceiving multi-lane corridors as faster traveling and those cyclists perceiving them as less safe. This finding has implications for continued investment in built environment solutions that include street reconfigurations, as well as for increased programs to education and reduce psychological/socio-cognitive barriers that may impede cycling behavior.

Carbon Trading: Who Gets What, When, and How?

Carbon Trading: Who Gets What, When, and How?

A Study on the Criteria Establishment for One-way road using AHP

A Study on the Criteria Establishment for One-way road using AHP

Analysis of one-way and two-way street configurations on urban grid networks

ABSTRACTIn this paper, we study traffic behavior on three different street configurations: one-way streets, two-way streets, and two-way streets with prohibited left turns. This study is novel because it employs three assignment and simulation methods to evaluate the networks under different conditions: analytical formulations, a Static Traffic Assignment algorithm, and a microsimulation software with a Dynamic Traffic Assignment. In general, the study reveals that two-way networks provide the shortest distance traveled but they are severely penalized by restrictions in capacity at the intersections. One-way networks offer the longest travel distances but have intersections with very high capacity. They perform better in congested scenarios. Finally, two-way networks with prohibited left turns provide the best compromise between distance travelled and intersection capacity, making them suitable for many different scenarios. Their main weakness is the lack of route redundancy that can lead to large travel times when networks are congested.

Phase diagram for one-way traffic flow with local control

We consider one-way road deterministic traffic model with N particles. The simplest local control protocol, which reminds physical interaction is considered. We obtain complete phase diagram uniformly in N and study in detail its stable and unstable domains.

“Outta my way!” Individual and environmental correlates of interactions between pedestrians and vehicles during street crossings

Because pedestrian crash rates remain lower than other collision types, surrogate measures such as traffic interactions are now used in road safety research to complement crash history. Using naturalistic data collection, we sought to assess 1) the likelihood of occurrence of interactions between pedestrians and vehicles based on individual and crossing characteristics; and 2) differences in interaction characteristics between children, adult and senior pedestrians. Observations of pedestrian crossing behaviours (n=4687) were recorded at 278 crossings. For recorded interactions (n=843), information was collected to characterize the behaviours of involved parties. A mixed-effect logit regression model was performed to assess the factors associated with interactions. Chi-square tests evaluated differences between age groups and characteristics of observed interactions. Older adults were those more likely to be involved in an interaction event. Bicycle paths, different crossing surface material and one-way streets were significantly associated with fewer interactions with vehicles, while parked vehicles nearby and crossings on arterial roads were significantly associated with more interactions. Children and the elderly (80 years of age or more) did have distinct patterns of interaction, with more careful drivers/cyclists behaviours being observed towards children and lesser regulation compliance towards the elderly. Given the growing emphasis and adoption of active transportation in many cities, the number of interactions between pedestrians and vehicles during street crossings is likely to increase. Educating drivers and pedestrians to respect each other's space requires an understanding of where, between whom, and under what circumstances interactions occur. Such an approach can also help identify which engineering and enforcement programs are needed to ensure safe pedestrian crossings since interactions can be good markers of uncomfortable crossing situations that may deter walking and lead to more collisions.

Multivariate Poisson-lognormal model for analysis of crashes on urban signalized intersections approach

ABSTRACTMany studies investigate contributing factors of intersection crashes, but very limited studies focus on cashes on the intersection approach. It is important to address the characteristics of intersection-approach crashes to better understand intersection safety. This article analyzes the crashes on signalized intersection approach on urban arterials with a focus on traffic and geometric elements. The intersection approach is defined as the segment between stop bar and the location 200 ft upstream from the stop bar. The multivariate Poisson log-normal (MVPLN) model is used to model crash counts by severity. Ten-year crash data collected from 643 signalized intersections in Nebraska are used for analysis. One-way road is found to be negatively related to all three severity levels (light crash, moderate crash, and severe crash) of crashes. Compared to the 12 ft lane width, narrower lane widths generally lead to fewer crashes. The intersection approaches on urban arterials are expected to have more crashes than collector roads. The numbers of right-turn, left-turn, and through lanes, as well as the annual average daily traffic on the intersection approach and its crossing approach are statistically significant factors increasing crash frequency. The MVPLN model is compared to univariate and zero-inflated Poisson models. The results reveal that the MVPLN model provides a superior fit over the univariate Poisson model.