Rate Of Travel Research Articles

Modeling precaution, immunity loss and dispersal on disease dynamics: a two-patch SIRS model

An SIRS model is developed to account for precautionary measures and immunity loss. The existence and stability of equilibria are studied. It is shown that precautionary measures can induce Hopf bifurcations leading to the occurrence of cyclical behavior. The model is then extended to a two-patch scenario to explore how disease spread patterns are influenced by dispersal (travel). Theoretical analyses establish the stability of the disease-free equilibrium, the basic reproduction number, and thresholds related to travel rates. The persistence of the system, as well as the existence of boundary and endemic equilibria, are also discussed. Using Hopf bifurcation theory, we further examine the interaction between nonlinear incidence functions, travel rates, and precaution delay effects in shaping the stability of the endemic equilibrium. The findings reveal a strong connection between reduced infection rates due to precaution and the emergence of Hopf bifurcations, emphasizing the importance of timely and accurate disease information in curbing the spread of diseases. Additionally, the study highlights the significant impact of different infection force functions on equilibrium stability, underscoring the critical role of precautionary measures in disease transmission mechanisms. The results also show the diverse effects of travel rates on disease spread, suggesting that restricting travel may not always lead to favorable outcomes. This underscores the necessity for governments to consider multiple factors comprehensively in their efforts to prevent and control diseases.

Unmanned Aerial Vehicles Used to Assess Performance of Automated Detection and Audio Deterrent System for Reducing Wind-Turbine Collision Risk for Golden Eagles

ABSTRACT DTBird is an automated detection and audio deterrent system designed to discourage birds from approaching spinning wind turbines. With Golden Eagles (Aquila chrysaetos) the focal species of interest, we evaluated DTBird’s performance at two commercial facilities, one situated in a desert landscape in California, USA (Manzana site), and the other in a temperate grassland/scrub landscape on a ridgeline above the Columbia River in Washington, USA (Goodnoe Hills site). To evaluate DTBird’s detection and deterrent-triggering functions, we used fixed-wing unmanned aerial vehicles (UAVs) as eagle surrogates in experimental flight trials, involving planned transect arrays that supported evaluating DTBird responses within a 240-m-radius expected maximum, hemispheric detection envelope. We quantified the probability of detection and used logistic regression to evaluate the influence of several predictors. We also built a general linear mixed-effects model (GLMM) to evaluate the influence of several environmental covariates and flight metrics on DTBird detection and deterrent-triggering response distances. The estimated probability of detection was similar at the two sites (64–66%), increased from morning through afternoon (effects of sun positioning), and was highest when the target flew at moderate distances from the turbine through the midsection of the camera viewsheds. The GLMM analysis confirmed modest variation relating to the five distinct UAV models used, possibly mimicking variation that would apply to eagles of variable size and coloration. The analysis also demonstrated that response distances averaged marginally shorter at the Manzana site and increased (suggesting improved detectability) under uniform cloud cover and as the UAV travel rate and exposure of the UAV profile to the cameras increased. Our experience also emphasized that effective use of foam-bodied, fixed-wing UAVs as eagle surrogates at wind facilities can be strongly limited by complicated topography that restricts centralized flight operations; intervening obstacles such as overhead powerlines that restrict automated flight missions; and excessive wind, inclement weather, and rough landing conditions around many turbines that can easily lead to UAV crashes and damage. Using eagle-like UAVs with immobile wings as eagle surrogates also might have constrained the insights generated from the study. Nevertheless, the indicated relationships can help future system users understand the environmental conditions in which DTBird and similar automated systems are likely to perform best and other factors that can substantially influence the targeting accuracy of such systems.

Evaluation of risk-based travel policy for the COVID-19 epidemic in Scotland: a population-based surveillance study

ObjectivesWe aimed to assess the effects of risk-based travel restrictions on (1) international travel frequency, (2) SARS-CoV-2 case importation risk, (3) national SARS-CoV-2 incidence and (4) importation of SARS-CoV-2 variants...

A singular, broadly-applicable model for estimating on- and off-path walking travel rates using airborne lidar data

Accurate prediction of walking travel rates is central to wide-ranging applications, including modeling historical travel networks, simulating evacuation from hazards, evaluating military ground troop movements, and assessing risk to wildland firefighters. Most of the existing functions for estimating travel rates have focused on slope as the sole landscape impediment, while some have gone a step further in applying a limited set of multiplicative factors to account for broadly defined surface types (e.g., “on-path” vs. “off-path”). In this study, we introduce the Simulating Travel Rates In Diverse Environments (STRIDE) model, which accurately predicts travel rates using a suite of airborne lidar-derived metrics (slope, vegetation density, and surface roughness) that encompass a continuous spectrum of landscape structure. STRIDE enables the accurate prediction of both on- and off-path travel rates using a single function that can be applied across wide-ranging environmental settings. The model explained more than 80% of the variance in the mean travel rates from three separate field experiments, with an average predictive error less than 16%. We demonstrate the use of STRIDE to map least-cost paths, highlighting its propensity for selecting logically consistent routes and producing more accurate yet considerably greater total travel time estimates than a slope-only model.

Wildland Firefighter Estimated Ground Evacuation Time Modeling to Support Risk-Informed Decision-Making

Wildland firefighters often work in remote settings with multiple hazards that can cause life-threatening injuries. Prompt access to medical care is key to reducing injury consequences. For the last decade, a spatial model of wildland firefighter estimated ground evacuation time (GET) has been used when developing operational response strategies in the contiguous United States (CONUS). This paper describes our updated and improved GET model and the resulting decision support spatial data representing the estimated time to evacuate to a hospital from anywhere within the CONUS using ground transportation only. The new GET model leverages updated input datasets and has improved off-road travel time estimation methods that incorporate the latest science on how terrain slope influences pedestrian travel rates. It also accounts for a novel set of landscape variables not previously considered, including minor roads and trails, streams, woody debris, cliffs, and an improved handling of shrub cover. When compared to a set of recent safety incidents, the reported evacuation times were correlated with the model predictions. The spatial patterns of GET from the new model are similar to the old product; however, we found that, on average, the new version of GET yields slightly faster evacuation times, but with regional variation in this trend.

Framework for analyzing the relationship between supply, demand, and flow of recreational services in urban park green spaces

Regular recreational activities in urban park green spaces are beneficial to the physical and mental health of residents. The supply capacity of, the residents’ demand for, and the actual flow of recreational services must be distinguished and evaluated to promote the fair and reasonable layout of urban park green spaces. However, the unit dimensions of the supply, demand, and flow indexes of recreational services are often inconsistent or only in simple semiquantitative forms, which cannot be directly compared and analyzed. Thus, this study constructed a research framework of “potential supply/demand–pressure/accessibility–actual supply/demand” for recreational services, and the framework was tested using the central urban area of Xuchang as the experimental area. Results show the following: (1) A spatial mismatch exists in the supply–demand relationship of recreational services in the study area; this relationship is reflected in the semicircular layer structure from the central and southern areas to the periphery, changing from shortage of supply to oversupply. (2) The actual supply of recreational services is highly correlated with the number of people served, which can explain 50.38% of the change in the actual supply. (3) The potential demand for recreational services is highly correlated with the actual demand. It can explain 78.96% of the change in the actual demand. (4) Accessibility is a non-critical factor affecting the travel rate of residential quarters, while supply pressure is a key factor affecting the utilization rate of park green space. The framework can effectively identify important or low-utilization service-providing areas, unmet service-demanding areas, and important service-connecting areas. It is suitable for the study of the relationship between the supply, demand, and flow of user movement-related services.

Pinpointing the role of wave period in vegetation induced wave attenuation

Nature-based coastal protection that integrates vegetated wetlands for wave attenuation and erosion mitigation shows great potential. However, there is a lack of consensus on whether longer wave periods contribute to an increase or a reduction in the attenuation of waves in vegetated wetlands, which is primarily due to the disregard of vegetation submersion states. In the current study, we modified a classic model to pinpoint the conditional role of the period. Wave attenuation by vegetation is quantified as the product of two terms: wave decay rate and time of wave group travel through a unit length. By tracing the dynamics of these two terms, the model is in good agreement with the measurements and can well explain why wave attenuation increased with longer period (from 2 to 10 s) in submerged canopies (up to 10 times) but decreased in emergent canopies (by 75%). A maximum response period (2–10 s) was found, beyond which period has no effect on wave attenuation. Furthermore, we found that in field conditions, the variation in wave period can lead to a sharp reduction in wave dissipation. which is critical for coastal safety. For instance, a 62% decrease in wave period at Galveston Island corresponded to a 40% drop in wave dissipation. This work provides a comprehensive understanding on the role of wave period in wave dissipation by wetland vegetation, which would assist in safely implementing wetlands for coastal defence.

Numerical simulation and experimental investigation on friction stir welding of AZ31 magnesium alloy

Integrated numerical simulations and experimental investigations were employed to scrutinize the thermal, mechanical, and microstructural transformations of the AZ31 magnesium alloy during the friction stir welding (FSW) process. Especially, the primary focus was on the influence of process parameters such as rotational speed and welding speed on the temperature distribution, grain refinement, and mechanical properties of welded joints in alloys. By employing Deform-3D coupled with the integration of constitutive equations and dynamic recrystallization (DRX) models, the FSW process was investigated. The investigation revealed a significant increase in temperature when the tool’s shoulder made contact with the weld, resulting in the substantial accumulation of heat during FSW. Distinctions became apparent between the advancing side (AS) and the receding side (RS), with the AS exhibiting slightly elevated levels of temperature, equivalent stress, strain, and grain size. Specifically, adjustments in the rotational speed of the stirring tool and a reduction in welding speed resulted in larger grain sizes within the alloy. For example, when the rotational speed was set at 1200 rpm and the travel rate was 200 mm min−1, the initial grain size of the weld experienced a substantial decrease from 57.8 μm to 8.2 μm. Subsequent experimental verification, considering grain size and microhardness, was carried out to optimize FSW parameters for achieving the desired material properties. The accuracy of simulation results was validated through a meticulous comparison with experimental findings, underscoring the potential of numerical simulation in comprehending and predicting FSW processes.

Influence of a Pair of Unequal Rotational Fluxes on Entrained Gaseous Filament

Abstract Efforts are made to elucidate a comprehensive analysis of entrainment dynamics triggered by a couple of unequal rotational fluxes within a viscous pool. Cylindrical rollers are employed to establish the rotational field. The top drum is equally submerged in both phases and also it provides a constant rotational inertia. Concomitantly, the bottom roller is completely submerged in the viscous bath, and it provides an unequal rotational strength in reference to top roller. The average rotational strength of both rollers is measured using average Capillary number (Caavg). The entrainment phenomenon is strongly influenced by both Caavg and gap between the rollers (W/D). Characterization of entrained filament is elucidated by predicting the horizontal distance (L*), radial distance (r*), temporal vertical displacement (Y*), maximum vertical displacement (Ymax*), width (H*), and location of V-shaped diversion (Øs*). Characterization of liquid tip is performed by measuring the travel rate (γ*) along periphery of drum from receding to advancing junction. Air mass ejection from filament tip is analyzed by estimating the first bubble ejection time (t1st*), volume of accumulated of ejected gaseous masses (v*), and ejection frequency (f). Furthermore, the effect of gravitational pull (specified by Archimedes number, Ar) and viscous drag (measured by Morton number, Mo) on the pattern of entrained air filament is described. Lastly, an analytical framework is established to determine the width of the V-junction by balancing the important influencing forces, which are strongly affecting the filament. Analytical observations show a satisfactory agreement with numerical findings.

Pengaruh Aksesibilitas Jalan Ende – Nuabosi Terhadap Peningkatan Perekonomian Masyarakat Kecamatan Ende

Nuabosi is one of the villages in the Ende District area, where this village helps improve the economy of Ende District in terms of meeting economic needs, namely in the form of various agricultural and plantation products. However, even though Nuabosi Village is sufficient to meet the economic needs of Ende District, distance and inadequate infrastructure conditions are some of the factors that influence the level of accessibility in Ende District. This research aims to determine the value and level of accessibility in the villages of Ende District. The accessibility measuring parameter data used is travel time, road pavement conditions, supporting facilities, and travel rates or costs. Data analysis uses quantitative descriptive analysis and crosstab analysis methods, using the total accessibility calculation formula. The results of the analysis based on a review of accessibility parameters and crosstabs show that the highest accessibility value for each village is Ria Raja Village with a value of 2.18 and the lowest is Tina Bani Village with a value of 0.37. The average level of accessibility in Ende District as a whole is 0.83, indicating a high level of accessibility, where the existing road conditions can influence the improvement of the economy of the people in Ende District. Crosstab analysis also shows that most of the factors determining accessibility are related to the socio-economic conditions of the community.

Fabricating Precise and Smooth Microgroove Structures on Zr-Based Metallic Glass Using Jet-ECM.

Zr-based metallic glasses (MGs) are promising materials for mold manufacturing due to their unique mechanical and chemical properties. However, the high hardness of metallic glasses and their tendency to crystallize at high temperatures make it challenging to fabricate precise and smooth microscale structures on metallic glasses. This limitation hampers the development of metallic glasses as molds. Jet electrochemical machining (jet-ECM) is a non-contact subtractive manufacturing technology that utilizes a high-speed electrolyte to partially remove material from workpieces, making it highly suitable for processing difficult-to-machine materials. Nevertheless, few studies have explored microgroove structures on Zr-based MGs using sodium nitrate electrolytes by jet-ECM. Therefore, this paper advocates the utilization of the jet-ECM technique to fabricate precise and smooth microgroove structures using a sodium nitrate electrolyte. The electrochemical characteristics were studied in sodium nitrate solution. Then, the effects of the applied voltages and nozzle travel rates on machining performance were investigated. Finally, micro-helical and micro-S structures with high geometric dimensional consistency and low surface roughness were successfully fabricated, with widths and depths measuring 433.7 ± 2.4 µm and 101.4 ± 1.6 µm, respectively. Their surface roughness was determined to be 0.118 ± 0.002 µm. Compared to non-aqueous-based methods for jet-ECM of Zr-based MGs, the depth of the microgrooves was increased from 20 μm to 101 μm. Furthermore, the processed microstructures had no uneven edges in the peripheral areas and no visible flow marks on the bottom.

Measuring the level of urban traffic congestion for sustainable transportation in Addis Ababa, Ethiopia, the cases of selected intersections

Traffic congestion poses a persistent and escalating problem for major cities in both developed and developing countries, exerting a direct impact on the economic growth and development of these urban areas. Quantifying the extent of traffic congestion is the fundamental initial step in comprehending the severity of traffic congestion in order to devise effective methods for alleviation. The city of Addis Ababa is currently experiencing significant traffic congestion at its main intersections. The primary aim of this research is to assess the current level of traffic congestion at specific intersections. The assessment of traffic congestion was conducted using the travel time method. Data on travel time, traffic volume, and travel speed were gathered at three blocks and two intersections using a combination of quantitative and qualitative data collection methods. The travel rate, delay rate, and total travel delay (in vehicle-minutes) were computed. The total vehicle-minute delay for the selected three segments is estimated to be approximately 12,708 vehicle-minutes (or 212 vehicle-hours). The text reveals the significance of measuring the various components of traffic congestion in order to ensure a sustainable traffic system. It also highlights the importance of maintaining a satisfactory level of service for the future sustainability of City.

An escape route planning model based on wildfire prediction information and travel rate of firefighters

Background When firefighters evacuate from wildfires, escape routes are crucial safety measures, providing pre-defined pathways to a safety zone. Their key evaluation criterion is the time it takes for firefighters to travel along the planned escape routes. Aims While shorter travel times can help firefighters reach safety zones faster, this may expose them to the threat of wildfires. Therefore, the safety of the routes must be considered. Methods We introduced a new evaluation indicator called the safety index by predicting the growth trend of wildfires. We then proposed a comprehensive evaluation cost function as an escape route planning model, which includes two factors: (1) travel time; and (2) safety of the escape route. The relationship between the two factors is dynamically adjusted through real time factor. The safety window within real time factor provides ideal safety margins between firefighters and wildfires, ensuring the overall safety of escape routes. Key results Compared with other models, the escape routes planned by the final improved model not only effectively avoid wildfires, but also provide relatively short travel time and reliable safety. Conclusions This study ensures sufficient safety margins for firefighters escaping in wildfire environments. Implications The escape route model described in this study offers a broader perspective on the study of escape route planning.

Acoustic telemetry tracking of Coho Salmon smolts released from a community-run hatchery into a marine inlet reveals low early ocean survival

Abstract Objective Hatcheries are used to help supplement populations of Pacific salmon Oncorhynchus spp. for conservation and fisheries purposes and to provide stewardship opportunities. In British Columbia, small community-run hatcheries typically focus on the latter and generally do not know the efficacy of their release approaches, unlike larger production hatcheries. Methods We used acoustic telemetry to track the survival and behavior of 90 hatchery-reared Coho Salmon O. kisutch smolts, released from a community hatchery, through Burrard Inlet and into the Strait of Georgia. This is the first study to track Coho Salmon smolts released directly into a marine environment and one of very few studies to track them in an oceanic setting. Result Smolt survival was lowest through the first 3 km of the migration at 37%, and the estimated cumulative survival to the final array (~20 km from release) was 10–23%. The presence of numerous predators in the region suggests that predation is a possible explanation for poor survival over the relatively short migration distance. Travel rates ranged from ~4 to 18 km/day, depending on the migration segment, which is slower than the marine migration of smolts from other species, likely increasing exposure to predators. However, we found potential evidence of “predator swamping,” as survival estimates across migration segments were highest for the final of our three release groups and poorest for the first release group, with intergroup survival estimates increasing by 7–12% in the final three migration segments. Releasing smolts at high densities and at night, as our partner hatchery currently does, likely improves smolt survival. Conclusion Our work demonstrates how acoustic telemetry can be used to examine hatchery practices and propose potential improvements. Saltwater readiness and the release location are factors that our results suggest may warrant future attention to potentially improve marine survival of Coho Salmon smolts.

Visual and genetic stock identification of a test fishery to forecast Columbia River spring Chinook salmon stocks 2 weeks into the future.

Modern fisheries management strives to balance opposing goals of protection for weak stocks and opportunity for harvesting healthy stocks. Test fisheries can aid management of anadromous fishes if they can forecast the strength and timing of an annual run with adequate time to allow fisheries planning. Integration of genetic stock identification (GSI) can further maximize utility of test fisheries by resolving run forecasts into weak- and healthy-stock subcomponents. Using 5 years (2017-2022) of test fishery data, our study evaluated accuracy, resolution, and lead time of predictions for stock-specific run timing and abundance of Columbia River spring Chinook salmon (Oncorhynchus tshawytscha). We determined if this test fishery (1) could use visual stock identification (VSI) to forecast at the coarse stock resolution (i.e., classification of "lower" vs. "upriver" stocks) upon which current management is based and (2) could be enhanced with GSI to forecast at higher stock resolution. VSI accurately identified coarse stocks (83.3% GSI concordance), and estimated a proxy for abundance (catch per unit effort, CPUE) of the upriver stock in the test fishery that was correlated (R 2 = 0.90) with spring Chinook salmon abundance at Bonneville dam (Rkm 235). Salmon travel rates (~8.6 Rkm/day) provided predictions with 2-week lead time prior to dam passage. Importantly, GSI resolved this predictive ability as finely as the hatchery broodstock level. Lower river stock CPUE in the test fishery was correlated with abundance at Willamette Falls (Rkm 196, R 2 = 0.62), but could not be as finely resolved as achieved for upriver stocks. We described steps to combine VSI and GSI to provide timely in-season information and with prediction accuracy of ~12.4 mean absolute percentage error and high stock resolution to help plan Columbia River mainstem fisheries.

Research on railroad locomotive driving safety assistance technology based on electromechanical coupling analysis

Abstract The reliability and effectiveness of a high-speed train’s operation depend heavily on the traction drive system. The purpose of this project was to construct an electromechanical connection model for a bullet train. The model contains the gear-to-gear connection, the differential output of the transmission, which circuits similar to those found in motors, and indirect power management. The purpose of this research is to investigate how modern railroad systems have implemented locomotive driving safety assistance technologies in order to get a deeper understanding of the effects that technological progress has on train operators. The purpose of this study is to learn how technological developments have altered the job of train operators. We will investigate the feasibility, compatibility, and potential consequences of introducing innovative technologies into established workflows. We will look at how well it works with current technologies, too. The current investigation has the authority to look at these issues. The ultimate goal of this project is to improve railway operations by providing essential insights for guaranteeing a balance between technological progress and human skill. The ultimate purpose of the project is to enhance the efficiency and security of railway operations. This may be achieved by strengthening the effectiveness and security of railway operations. In addition, the high-speed train model is simulated numerically to maintain that steady rate of travel, and grip, while slowing. The study determined that the stator current is the result of the interaction between the fundamental frequency and the higher harmonics of the rotational frequency. Furthermore, both frequencies can be detected even when traveling at a constant speed. Despite this, unless the rotation frequency is increased, they are often not visible. During traction, the root-mean-square (RMS) values of the rotor and stator currents are lower than that during braking. There is a significant rise in current when the wheels and brakes are first applied. The RMS value of the current lowers dramatically as grip and braking improve. As a result, it is essential to carefully consider how the change may influence the reliability of the system.

Monitoring the Effect of Weed Encroachment on Cattle Behavior in Grazing Systems Using GPS Tracking Collars

Weed encroachment on grasslands can negatively affect herbage allowance and animal behavior, impacting livestock production. We used low-cost GPS collars fitted to twenty-four Angus crossbred steers to evaluate the effects of different levels of weed encroachment on animal activities and spatial distribution. The experiment was established with a randomized complete block design, with three treatments and four blocks. The treatments were paddocks free of weeds (weed-free), paddocks with weeds established in alternated strips (weed-strips), and paddocks with weeds spread throughout the entire area (weed-infested). Animals in weed-infested paddocks had reduced resting time and increased grazing time, distance traveled, and rate of travel (p < 0.05) compared to animals in weed-free paddocks. The spatial distribution of the animals was consistently greater in weed-free paddocks than in weed-strips or weed-infested areas. The effects of weed encroachment on animal activities were minimized after weed senescence at the end of the growing season. Pasture weed encroachment affected cattle behavior and their spatial distribution across the pasture, potentially impacting animal welfare. Further long-term studies are encouraged to evaluate the impacts of weed encroachment on animal performance and to quantify the effects of behavioral changes on animal energy balance.

Examining the impact of tourism on economic growth in the Republic of South Africa

Examining the impact of tourism on economic growth in the Republic of South Africa (1995–2020) is the subject of this thesis. Tourism is widely recognized as one of the factors that contributes to a country's long-term economic development and helps to raise average income per person across the board. In this regard, international tourism makes a lot of positive contributions to economic growth in a variety of ways. One of the most fundamental reasons why tourism is so important is that money from tourism helps cover the country's need for foreign currency and, as a result, contributes to the reduction of the balance of payment deficit. Argue that, in addition to the information previously stated, the tourism industry contributes to economic development in a number of different ways. For example, tourism profits can be invested in fixed assets; tourism promotes a competitive market and investments in new facilities; tourism stimulates other sectors of the economy through direct, indirect, and induced effects; tourism creates job opportunities; and tourism promotes foreign travel and exchange rates. The ARDL model and the Granger causality test were utilized in this thesis to determine the connection between the dependent and independent variables. The findings suggest that tourism has a beneficial influence on South African economic development, but exports and exchange rates have a negative impact. Given that there is a causal link between tourism and economic development, our evidence of reliance may support the deployment of these strategies. All of this was done by using the Eviews statistical software. Also, when tourism is promoted and it is discovered that growth rates are interdependent, it may be acceptable to impose tourist laws since these rules take into consideration the degree of tail dependency that occurs between growth rates over time.

Effect of Tool Travel Rate on Microstructure Evolution and Mechanical Properties of Dissimilar Friction Stir Welded Joints of AA7075 and AA6061 Aluminium Alloys

Effect of Tool Travel Rate on Microstructure Evolution and Mechanical Properties of Dissimilar Friction Stir Welded Joints of AA7075 and AA6061 Aluminium Alloys

Rate of Emergency Lower Extremity Amputations in the United States Among Medicare Beneficiaries.

To determine the rate of emergency versus elective lower extremity amputations in the United States. Lower extremity amputation is a common endpoint for patients with poorly controlled diabetes and multilevel peripheral vascular disease. Although the procedure is ideally performed electively, patients with limited access may present later and require an emergency operation. To what extent rates of emergency amputation for lower extremities vary across the United States is unknown. Evaluation of Medicare beneficiaries who underwent lower extremity amputation between 2015 and 2020. The rate was determined for each zip code and placed into rank order from lowest to highest rate. We merged each beneficiary's place of residence and location of care with the American Hospital Association Annual Survey using Google Maps Application Programming Interface to determine the travel distance for patients to undergo their procedure. Of 233,084 patients, 66.3% (154,597) were men, 69.8% (162,786) were White. The average age (SD) was 74 years (8). There was wide variation in rates of emergency lower extremity amputation. The lowest quintile of zip codes demonstrated an emergency amputation rate of 3.7%, whereas the highest quintile demonstrated 90%. The median travel distance in the lowest emergency surgery rate quintile was 34.6 miles compared with 10.5 miles in the highest quintile of emergency surgery ( P < 0.001). There is wide variation in the rate of emergency lower extremity amputations among Medicare beneficiaries, suggesting variable access to essential vascular care. Travel distance and rate of amputation have an inverse relationship, suggesting that barriers other than travel distance are playing a role.