Buffer Index Research Articles

Travel Time Variability in Urban Mobility: Exploring Transportation System Reliability Performance Using Ridesharing Data

Travel time variability (TTV) is a crucial indicator of transportation network performance, assessing travel time reliability and delays. This study investigates TTV metrics within the context of shared mobility using probe data from transportation network companies (TNCs) in Chicago, Los Angeles, and Dallas–Fort Worth. Eight reliability metrics are analyzed and compared for each origin–destination (OD) pair in the network, including standard deviation (SD), the Planning Time Index (PTI), the Travel Time Index (TTI), the Buffer Index (BI), On-time Measures PR (alpha), and the Misery Index (MI), to evaluate their effectiveness in clustering OD pairs using K-means clustering. The findings confirm that SD, PTI, and MI are particularly effective in measuring travel time reliability and clustering within urban systems. This study identifies the most unbalanced supply–demand OD pairs/regions in each city, noting that low/medium-SD clusters around metropolitan airports indicate stable travel times even in high-demand zones, while high-SD clusters in downtown areas reveal significant traffic demands and unreliability. These patterns become more pronounced in study areas with multiple city centers. This study highlights the need for targeted strategies to enhance travel time reliability, particularly in regions like Dallas–Fort Worth, where public transportation alternatives are limited.

Analysis the Reliability of Travel Time in Urban Corridors in Baghdad City

Travel-time reliability is a crucial performance measure for transportation systems. This research aims to estimate travel time and predict delay time on three routes in Baghdad city using GPS devices: Safi Al-Den Street, Palestine Street, and the Army Channel Expressway. The study was conducted northward from 7:00 a.m. to 9:00 p.m. Reliability indices for the first and second routes with signalized intersections, including buffer index, travel time index, and 95th percentile travel time, were determined. Safi Al-Den Street's buffer time index for links 1 to 3 is approximately 44.75%, 39.87%, and 39.12%, respectively. The highest travel time index value is observed in link 3 at 8.9%. Link 1 has the longest 95% travel time at 659 seconds. Palestine Street shows a high buffer time index in links 1 and 3 at around 32.39% and 24.65%, respectively. The highest travel time index is in link 3 at 6.84%, attributed to congestion from increased educational, medical, and commercial trips. The longest 95% travel time is 430 seconds in link 7. This study offers valuable insights into the reliability of travel time in urban corridors in Baghdad city, aiding transportation planners and engineers in making informed decisions on traffic management, infrastructure development, and policy-making.

Validation of critical soil-test phosphorus values from the Better Fertiliser Decisions for Pastures meta-analysis

Context Historical application of phosphorus (P) fertilisers has enabled grazing agriculture in south-west Western Australia but has led to excessive soil P levels that pose a eutrophication risk. However, adoption of critical soil-test P values for pastures determined from the Better Fertiliser Decisions for Pastures (BFDP) meta-analysis of historical Australian trials has been poor because of perceived lack of relevance to the soils and contemporary pasture species in the region. Aims We aimed to validate critical Colwell P values from the BFDP project for soils and contemporary pasture species of south-west Western Australia. Methods Fifty P-rate response trials were performed with contemporary pasture species, and the results compared with BFDP. Key results Trial results were consistent with BFDP and fell within 95% prediction intervals of response calibrations of Colwell P and relative yield pairs for different P buffering index (PBI) ranges. Soils with PBI <15 required lower critical Colwell P values. Responsiveness to P application was 8% (±4%), consistent with a 5% response expected for Colwell P levels supporting 95% relative yield. Application of nitrogen, potassium and sulfur significantly increased yield while increasing basal cover of annual ryegrass (Lolium multiflorum) and reducing that of clover (Trifolium spp.) in the sward. Response calibration coefficients and critical Colwell P values before and after addition of the trial data to BFDP showed a strong correlation (r2 >0.99), although critical values were slightly lower for lower soil PBI. Conclusions Critical Colwell P values from BFDP are relevant and applicable to soils and contemporary pasture species of south-west Western Australia. Implications Agronomic advice and application of P should be based on interpretation of Colwell P values, with P applied only when levels are below the critical value. Pasture composition should also be considered when interpreting Colwell P values. This approach minimises risks of P loss and improves economic outcomes for growers.

Short‐term phosphorus sorption and desorption in contrasting cropped Vertisols

AbstractVertisols are important cropping soils in tropical and subtropical areas, but in many regions, decades of cropping has substantially reduced concentrations of plant‐available phosphorus (P), especially in the subsoil layers. Phosphorus behaviour in P‐depleted Vertisols has received comparatively little attention, and the availability of P following the addition of inorganic P fertilisers at different concentrations is poorly understood. In this study, we evaluated short‐term P sorption and desorption behaviour in cropped Vertisols in relation to specific soil physical and chemical properties. We collected the surface and subsurface of 15 Australian soils with a broad range of physical and chemical properties, comprising nine Vertisols, three Ferralsols, two Lixisols and one Calcisol. For each soil, we generated sorption and desorption curves (fitted with a Freundlich equation), determined soil physical and chemical properties likely to influence P sorption and evaluated the relationships between the measured soil properties and the Freundlich equation sorption coefficients. The P sorption curves differed drastically between soils, with the sorption equation coefficients (aS × b) significantly correlated with the P buffering index (PBI) and clay content. Clay content itself was correlated with citrate‐extractable Fe and Al oxides and BET surface area. Vertisols formed on basaltic parent materials had greater Fe and Al oxide concentrations, resulting in an overall greater P sorption capacity. Sorption and desorption hysteresis were mostly small. The reacting materials in these soils probably had limited ability to continue to react with P. The Vertisols differed in their capacity to replenish P in the soil solution by desorbing different proportions of previously sorbed P, although the proportion of desorbable P generally increased with greater concentrations of sorbed P. These results suggest that for fertiliser management in these soils, smaller volumes of P enrichment combined with higher P concentrations may result in a greater P recovery by the crop.

Numerical modeling of double-ring infiltrometers for determining saturated hydraulic conductivity in heterogeneous and anisotropic soils

Philip’s two-term infiltration equation has been widely used to infer soil saturated hydraulic conductivity (Ks), the accuracy of which is usually influenced by the size of infiltration rings and soil conditions. Previous studies have primarily focused on exploring the ring-size dependence of Ks estimations under specific soil conditions (e.g., soil isotropy and/or uniform initial water content). This study aims to provide a comprehensive analysis by systematically considering eight heterogeneous and anisotropic soils with non-uniform initial water contents. Specifically, we first examined the validity of Philip’s equation as well as the recently proposed two forms (i.e., infiltration- and time-form) of Parlange’s infiltration equations both theoretically and in practical applications of double-ring infiltration. Then the time form of Parlange’s infiltration equation was applied to infer Ks using double-ring infiltrometer measurements with different combinations of six inner ring diameters (di = 10, 20, 40, 80, 120, and 200 cm) and three buffer indices (i.e., defined as the ratio of the difference between inner and outer ring diameters to the outer ring diameter, here b = 0.2, 0.33, and 0.5). For each infiltrometer set, 20 stochastic Ks fields were randomly generated by adopting five standard deviation values (i.e., σlnKs = 0.1, 0.3, 0.5, 0.7, and 0.9). Furthermore, we investigated the influence of the horizontal correlation length (i.e., λx = 30, 60, 150, 300, and 600 cm) on Ks estimations. The results demonstrate that Parlange’s equation, compared to Philip’s equation, is more universal in describing the cumulative infiltration relationship for the test soils; the optimal combination of inner ring diameter and buffer index was 40 cm and 0.2, respectively, which satisfied most of the practical requirements for determining Ks in the Soil Water Infiltration Global (SWIG) database; when the horizontal correlation length exceeds a threshold (i.e., 150 cm in our study), the inner ring diameter is required to increase to 80 cm. Our findings contribute to accurate Ks estimations of different soils using double-ring infiltrometers.

The Contribution of Microrefugia to Landscape Thermal Inertia for Climate‐Adaptive Conservation Strategies

AbstractCurrent temperatures in microrefugia may persist longer than in nearby areas as temperatures warm. However, locating and measuring the contribution of microrefugia to thermal inertia in a landscape is challenging. We measured the thermal buffering capacity of microrefugia across a 40,000 km2 region of complex mountain topography by quantifying environmental lapse rate and solar radiation effects on air temperature in 0.1 km2 hexagons, a resource management‐relevant scale for climate adaptation. The greatest buffering capacity is −1.62°C, and only 2.8% of the region can buffer 1°C or greater. Historical loss of local cooling capacity is low, but by 2069 only 6.9%–11% of the region retains baseline temperature conditions. This thermal buffer index can find the most climate change‐buffered areas in lands identified as high priority for habitat conservation, wildlife corridors, and forest preservation. Other processes such as cold air pooling can complement our approach but depend on additional factors.

Impact of long-term fertilization in no-till on the stratification of soil acidity and related parameters

The increasing cost of fuel and machinery used in conventional tillage systems makes no-till management (NT) an enticing alternative for small-grain producers. However, the application of fertilizers to the soil surface under NT has been shown to lead to the stratification of pH and other soil acidity parameters near the soil surface. Despite that, only a few works have reported the soil acidity stratification of the arable layer and were restricted to highly weathered acid soils of the tropics. Therefore, our objective was to quantify soil pH, exchangeable aluminum (AlKCl), aluminum saturation (Al%), soil organic carbon (OC), and cation exchange capacity (CEC) by depth in the topsoils across different levels of nutrient management in three long-term continuous NT wheat studies in the southern Plains of US. Plots were sampled after the winter wheat (Triticum aestivum L.) harvest in the summer of 2019 at sampling depths of 0–15 cm, and 0–2.5, 2.5–5, 5–7.5, 7.5–10, 10–12.5, and 12.5–15 cm. Treatments included an unfertilized check and a combination of increased rates of nitrogen (N) in addition to phosphorus (P) and potassium (K) application across all study locations. It was found that stratification occurred for all soil acidity parameters tested in the study, with higher OC and AlKCl, and lower pH near the soil surface. Patterns of soil pH and OC stratification were generally related to the rate of annual N fertilization. The long-term N fertilization significantly reduced soil pH in the topsoil (0–15 cm) and stratified soil layers, especially at the higher application rates. Regardless of the soil sampling depth, pH decrease was significantly related to the amount of N applied. Also, N fertilization significantly increased AlKCl and Al% but decreased the sum of Ca2++Mg2++K++Na+ both in the whole topsoil or layers. AlKCl and Al% were increased exponentially and linearly with increasing N rate and were for 0–15 cm and stratified layers, respectively. AlKCl was exponentially (inversely) related to soil pH for both sampling methods. Nitrate (NO3) was inversely related to soil pH until up to 21.9 ± 2.6 mg NO3N kg−1. Although not at the same magnitude, non-fertilized plots were likewise stratified for the tested parameters, which indicates other effects of NT on the stratification rather than the fertilizer addition. Overall, the buffer index (BI) was lower if the soil is sampled from 0 to 2.5 cm than 0–15 cm. Attention regarding sampling depth in NT areas is essential for accurate soil attributes monitoring.

Agronomic soil tests can be used to estimate dissolved reactive phosphorus loss

Context Phosphorus (P) use in agriculture can lead to eutrophication. Agronomic soil tests such as Colwell P and P buffering index (PBI) define critical soil P levels for pasture production. These tests have potential for re-use as environmental risk indicators of dissolved reactive P (DRP) loss from paddocks but are constrained because a 0–10 cm sample does not necessarily align with the dominant hydrological loss pathways of runoff or leaching. Aims To identify influences on the benchmark environmental measure of DRP (CaCl2-extractable P or CaCl2-P) by agronomic-based measures such as PBI, Colwell P and depth, and Colwell P to PBI ratio (P environmental risk index; PERI). To estimate CaCl2-P at any depth from a 0–10 cm sample, and the potential for change in DRP loss risk through the adoption of evidence-based fertiliser management based on soil testing. Methods Archives of 692 0–10-cm soil samples, along with 88 sites sampled at 0–10 cm and 0–1, 1–2, 2–5, 5–10, 10–20, and 20–30 cm were analysed for Colwell P, PBI, CaCl2-P, PERI, and P fertility index (PFI). Derived relationships between CaCl2-P and Colwell P for different PBI were applied to 30 981 0–10-cm samples to estimate the potential for DRP reduction resulting from the adoption of evidence-based fertiliser management. Key results CaCl2-P, Colwell P, PERI, and PFI decreased with depth, with an associated increase in DRP loss risk from surface soil. The CaCl2-P decreased with increasing PBI. The CaCl2-P, Colwell P, PERI, and PFI could be estimated at any depth from a 0–10 cm sample, with r2 > 0.77. The CaCl2-P was estimable from PERI, and soils with low PBI or with high PFI had high DRP loss risk. The CaCl2-P was positively correlated with Colwell P, with the slope decreasing with increasing PBI and becoming invariant when PBI > 100. When applied to the current soil Colwell P and estimated current CaCl2-P and compared to CaCl2-P at the critical Colwell P for different relative yields (RYs), DRP loss risk could be reduced by 24% for a RY target of 95%, and 59% for a RY target of 80%. Conclusions Because current Colwell P levels in soils exceed critical values, DRP loss risk can be substantially reduced by adopting evidence-based fertiliser management with little or no loss of utilised pasture. Implications Fertiliser management based on evidence of P requirements determined from soil testing has a significant role in reducing DRP loss risk.

Assessment of Traffic Congestion under Indian Environment - a Case Study

Traffic congestion is a major problem around the globe. The prime reason for congestion is unavailability of traffic infrastructure to meet the traffic demand. Road users are forced to face undesirable delay, which influences the economy, environment and health. The present study examines the congestion in the urban roads of Bhubaneswar, a smart city in India. Travel time for various categories of vehicles was estimated and congestion indices in terms of buffer index were evaluated. Multiple linear regression modeling has been used to evaluate the congestion parameters. The p-value for all the independent variables in the developed model is < 0.05. Four elements, namely Strict traffic law implementation, Adequate parking facilities, Decentralization and Controlling the road side activities are required to improve the serviceability and mobility of urban road networks.

High Volume Freeway Travel Time Reliability and the COVID-19 Pandemic

This paper examines the effect of the COVID-19 pandemic on travel time reliability (TTR) performance on two high traffic volume freeway corridors (I-90 and I-405) in the U.S.A. Specifically, the travel time distributions (TTDs) during and before the pandemic are compared. The paper also examines which TTR metrics best capture the effect of the pandemic on reliability performance. There were statistically significant differences, at the 95% confidence level, between TTD in 2020 and corresponding TTDs in 2018 and 2019. Not surprisingly, all measures of central tendency and all measures of dispersions were reduced during the pandemic. Consequently, it was concluded that TTR performance improved during the pandemic regardless of what TTR definition was used. Travel time index (TTI), planning time index (PTI), and the level of travel time reliability (LOTTR) metrics improved during the pandemic, albeit at different rates. In contrast, the buffer index and coefficient of variation increased. In other words, whether an analyst would identify that TTR improved or decreased during the pandemic, and by how much, would be a function of which TTR metric was applied. Not surprisingly, the more congested the roadway section, the greater the impact the pandemic-related interventions had on TTR. It was found that, practically speaking, there are no differences in TTI, PTI, or LOTTR values when TTDs are formulated using a 5 min or 15 min aggregation interval. It was concluded that analysts need to have a deep understanding of the underlying TTD and the various TTR definitions when evaluating changes in freeway systems’ TTR.

Influence path identification of topography, soil, hydrology and landscape on phosphorus buffering capacity in typical agricultural catchments in central subtropical China

The catchment phosphorus buffering capacity (PBF) determines the pressure-state-response relationship between anthropogenic P inputs and aquatic ecosystems at a catchment scale, and is affected by biogeochemical, hydrological, and ecological catchment characteristics. However, the complex relationship between these catchment characteristic factors and their impact pathways on PBF remains ambiguous, leading to large uncertainty in balancing agricultural productivity and water conservation via improving BF through management practices. In this study, the short-term buffering index, calculated from net anthropogenic P input and riverine P exports, was used to quantify the spatiotemporal variations in PBF in source agricultural catchments in the Dongting Lake basin. Partial least squares structural equation modeling was used to investigate the relationship between the PBF and the catchment characteristics. The results indicate that catchment PBF was directly determined by soil properties and hydrological conditions, while landscape patterns significantly mediated the effects of topography on soil and hydrology. Considering the pathway preferences of the model, landscape patterns could be the priority for characterizing and regulating PBF. According to a change-point analysis, the probability of PBF weakening increases dramatically when the proportion of farmland (Farm%) > 24.6%, degree of patch interspersion (Contagion index) < 64.5%, and Perimeter-Area Ratio Distribution (PARA) > 348.7. These findings provide new insights into catchment buffering mechanisms and can be used to promote the simultaneous achievement of agricultural production and environmental conservation goals.

Valuable phosphorus retained by ironstone gravels can be measured as bicarbonate extractable P

The > 2 mm fraction of soils is often excluded from laboratory analysis and glasshouse experiments, but is known to influence whole soil physical, chemical and biological properties. The historical focus on the < 2 mm fraction has led to a knowledge gap in analytical procedures and flow-on effect for agronomic response and advice when the > 2 mm fraction is present, especially when it is porous and chemically reactive.An ironstone gravel soil (Endopetric Pisoplinthic Plinthosol (Arenic)) from south west Western Australia was separated into < 2, 2–4, 4–6, 6–8 and 8–10 mm fractions. Physical analysis included specific surface area (SSA), optical mineralogy, XRD and SEM. Chemical analysis included phosphorus (P) sorption, P retention index (PRI), P buffering index (PBI) and sodium bicarbonate extractable P (Cowell P) on intact and ground samples, and intact mixtures of the < 2 mm and > 2 mm fractions. Δ NaF pH was used as a surrogate P retention measure on intact mixtures of the < 2 mm and > 2 mm fractions.P adsorbed onto the > 2 mm fraction can be measured as Colwell P, suggesting this fraction can provide P to plants. Colwell P determined on ground samples was correlated 1:1 with Colwell P on intact counterparts. Grinding of samples resulted in large increases in PRI and PBI, and is not a supported sample preparation, neither is the use of end over end shakers due to surface abrasion of the > 2 mm fraction increasing P sorption, however the use of Δ NaF pH as a surrogate measure of P sorption offers some potential.Phosphorus adsorption decreased with increasing particle size but adsorption by the > 2 mm fraction is likely significant in the context of an entire unsieved soil and was influenced by SSA. The > 2 mm fraction had higher SSA than their physical size would imply, possibly influenced by the thickness and mineralogy of the exterior coating (rind). Our results show that the > 2 mm fraction contains reactive surfaces that can contribute to the nutrient holding capacity and plant available P of soils.

A New Approach to Optimize pH Buffers**

AbstractBuffer solutions are pervasive in chemistry, biochemistry, analytical chemistry, etc. A better understanding of buffer properties and what controls them is susceptible to be of interest in many scientific and technological fields. For instance, linear pH gradients are commonly used in electrophoresis and their optimization rests on numerical optimization of the concentrations of various weak species. It is probably generally assumed that no basic progress could be made on optimization approaches. We introduce here a new strategy to buffer optimization, based on a parametric study of the roots of the first derivative of the buffer index. In this way, it is possible to find mathematically optimal sets of parameters (pKa and concentrations). The method is applied to mixtures of 2, 3 and 4 monovalent species, which represent simple cases that do not call for overly elaborate numerical optimization techniques, but are nevertheless of practical interest in various branches of analytical chemistry.

Evaluation of travel time reliability in urban areas using mobile navigation applications in Jordan

This study aims to assess the Travel Time Reliability (TTR) in urban areas in Irbid city, Jordan, using a mobile application (Ultra GPS Logger), which retains the current location, speed, and time every three seconds. The study evaluated the TTR at the Origin-Destination (OD) level and the segment level. Each OD was divided into several segments with different interruption types to determine which segments have the lowest reliability and the most extended delay. The evaluation was based on several measures according to the Federal Highway Administration (FHWA), such as the buffer time, Buffer Index (BI), Travel Time Index (TTI), 95th percentile, standard deviation, and Coefficient of Variation. Chi-Square test for independence was carried to study the association between the period during the day, day of the week, and section type with the BI Level, and other combinations. Results showed that the normal sections, without traffic signals and roundabouts, had a significant effect on TTR compared with 3-Leg intersections, 4-Leg intersections, and roundabouts. Results also confirmed that trips reliability does not mean there is no delay or congestion, but there is some certainty in travel time prediction for a specific route and journey.

TRAVEL TIME RELIABILITY INDICES FOR URBAN ROUTES IN BAGHDAD CITY

Reliability is one of the main metrics of transport system efficiency and quality of service. For both travelers and transport management organizations, the high variance of road travel times has become a problem. Reliability has been identified as one of the main areas of interest of the Strategic Highway Research Plan II. In order to evaluate congestion and unexpected changes in travel time, reliability metrics are increasingly used. GPS devices provide for exact assessment of travel time for each connection along the routes used for this research. (14 Ramadan arterial street, Al-Karada arterial street and Damascus arterial street). A GPS-equipped instrumented car was used to gather 50 test runs at peak and off peak times. At peak and off peak hours, 50 test runs were obtained using a GPS-equipped instrumented car. Raising the buffer time index results in inferior conditions for reliability. A buffer index of AL- Karada street was created about 53% and 30% for Damascus street and finally for 14 Ramadan street which present a 29% buffer index for north direction. As for its southern direction 14 Ramadan street created a buffer index of about 65% and 33% for AL- Karada street and finally for Damascus street which present a 29% buffer index. In addition, travel time index for (14 Ramadan street, AL- Karada street and Damascus street) respectively is about 2.8 %, 3.3% and 2.6% for north direction, as for its southern direction the travel time index is obtained for (14 Ramadan street, AL- Karada street and Damascus street) respectively were a 3%,3.7%, and 2.5%. Finally, the 95% percentile travel time for observed three selected routes in this study, the extra delay was felt on each route (1627, 2212, and 1192) sec. for (14 Ramadan street, AL- Karada street and Damascus street) for north direction, as for its southern direction the extra delay that perceived on each route (2221, 2132, and 975) sec. for (14 Ramadan street, AL- Karada street and Damascus street) respectively.

Integrating critical chain project management with last planner system for linear scheduling of modular construction

PurposeThe purpose of this paper is to present a new method for project tracking and control of integrated offsite and onsite activities in modular construction considering practical characteristics associated with this type of construction.Design/methodology/approachThe design embraces building information modelling and integrates last planner system (LPS), linear scheduling method (LSM) and critical chain project management (CCPM) to develop tracking and control procedures for modular construction projects. The developed method accounts for constraints of resources continuity and uncertainties associated with activity duration. Features of proposed method are illustrated in a case example for tracking and control of modular projects.FindingsComparison between developed schedule and Monte Carlo simulation showed that baseline duration generated from simulation exceeds that produced by developed method by 12% and 10% for schedules with 50% and 90% confidence level, respectively. These percentages decrease based on interventions of members of project team in the LPS sessions. The case example results indicate that project is delayed 5% and experienced cost overrun of 2.5%.Originality/valueDeveloped method integrated LPS, LSM and CCPM while using metrics for reliability assessment of linear schedules, namely, critical percent plan complete (PPCcr) and buffer index (BI). PPCcr and BI measure percentage of plan completion for critical activities and buffer consumption, respectively. The developed method provides a systematic procedure for forecasting look-ahead schedules using forecasting correction factor Δt and a newly developed tracking and control procedure that uses PPCcr and BI. Quantitative cost analysis is also provided to forecast and monitor project costs to prove the robustness of proposed framework.

Sharp Front analysis of moisture buffering

Moisture buffering describes the use of materials with high water-vapour sorption capacity to provide humidity control&#x0D; in interior spaces. Established models of the moisture dynamics of buffering are derived from conventional Fickian vapour-diffusion&#x0D; equations. We describe an alternative analysis using a Sharp-Front formulation. This yields a similar expression for the &#x0D; moisture effusivity, several consistent scalings and a new definition of the moisture penetration depth. Features of the model are compared with &#x0D; some published experimental data. A new sorption buffer index is a measurable experimental property that describes the water-vapour &#x0D; buffer strength of the material.

Arterial Roadway Travel Time Reliability and the COVID-19 Pandemic

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.

The Response of Soil pH and Exchangeable Al to Alum and Lime Amendments

Intensive cultivation and unprecedented utilization of ammoniacal fertilizer has accelerated soil acidification in the southern Great Plains and many other parts of the world. During a two-year study that evaluated the impact of soil pH and aluminum (Al) toxicity on winter wheat yield potential, we observed a variance in the edaphic responses of the two study sites (Stillwater and Chickasha) to two soil amendments, Alum [Al2(SO4)3] and lime [Ca(OH)2]. We found that AlKCl values at Stillwater were 223% and 150% higher than Chickasha during Year 1 and Year 2, respectively, with similar soil pH. Additionally, Alsat values at Stillwater were 30.6% and 24.9% higher than Chickasha during Year 1 and Year 2, respectively. Surprisingly, when treated as a bivariate of Alsat, soil buffer indices differed in graphical structure. While Chickasha was identified with a cubic polynomial (p &lt; 0.0001), Stillwater was characterized by linear regression (p &lt; 0.0001). We have reason to believe that this divergence in edaphic response might be attributed to the organically bound Al, dissolved organic carbon (DOC), spatio-temporal variance, and adsorption reactions regulated by the solubility of Al(OH)+2 species in acidic soils.

Impact of Side Friction on Travel Time Reliability of Urban Public Transit

Travel time reliability is the key aspect that indicates the quality of urban public transit service. The studies on travel time reliability of the public transit system in Indian traffic conditions are few. Also, the impact of side friction elements on travel time reliability has not been considered in the previous studies. Hence, the present study aims to quantify the different types of side friction elements and analyse their impact on the travel time reliability of the public bus transit system. The field data consisting of side friction elements, traffic volume, and travel time of public bus transit have been collected and extracted at two different road sections (divided and undivided) in the Mysore city (Karnataka, India) during weekdays and weekends. The data are grouped into static and dynamic side frictions. An approach has been proposed to represent different types of side friction elements with a single index called the Side Friction Index (SFI) using relative weight analysis. Travel time reliability is represented using measures such as Buffer Time Index (BTI), Planning Time Index (PTI), Travel Time Index (TTI) and Reliable Buffer Index (RBI). The impact of side friction on travel time reliability was found to be sensitive to traffic volume, and hence the thresholds for different traffic volume levels have been determined using K-means clustering method. It was observed from relative weight analysis that the static side friction has a higher weightage (0.509 and 0.327 for the undivided road and divided road respectively) than the dynamic side friction elements in describing the variation of travel time. The impact of side friction on reliability measures at different traffic volume levels has been studied and found to have a non-linear (exponential) relationship. The impact of SFI has been observed to be higher on TTI and PTI in comparison with BTI. The study outcomes show that the impact of side friction on TTI and PTI is sensitive to traffic volume, especially at higher traffic volume level and impact of side friction on BTI is less, especially at medium traffic volume level. The inference from the study shows that the impact of side friction elements varies with respect to the type of road (divided and undivided), traffic volume levels, different days of week (weekday and weekend), and different time periods of day.