Mobility Performance Measures Research Articles

Impact of Privacy Filters and Fleet Changes on Connected Vehicle Trajectory Datasets for Intersection and Freeway Use Cases

Commercially available crowdsourced connected vehicle (CV) trajectory data have recently been used to provide stakeholders with actionable and scalable roadway mobility infrastructure performance measures. Transportation agencies and automotive original equipment manufacturers (OEMs) share a common vision of ensuring the privacy of motorists that anonymously provide their journey information. As this market has evolved, the fleet mix has changed, and some OEMs have introduced additional fuzzification of CV data around 0.5 miles of frequently visited locations. This study compared the estimated Indiana market penetration rates (MPRs) between historic non-fuzzified CV datasets from 2020 to 2023 and a 5–11 May 2024, CV dataset with fuzzified records and a reduced fleet. At selected permanent interstate and non-interstate count stations, overall CV MPRs decreased by 0.5% and 0.3% compared to 2023, respectively. However, the trend in previous years was upward. Additionally, this paper evaluated the impact on data characteristics at freeways and intersections between the 5–11 May 2024, fuzzified CV dataset and a non-fuzzified 7–13 May 2023, CV dataset. The analysis found that the total number of GPS samples decreased 10% statewide. Of the evaluated 54,284 0.1-mile Indiana freeway, US Route, and State Route segments, the number of CV samples increased for 33.8% and decreased for 65.9%. This study also evaluated 26,291 movements at 3289 intersections and found that the number of available trajectories increased for 28.3% and decreased for 70.4%. This paper concludes that data representativeness is enough to derive most relevant mobility performance measures. However, since the change in available trajectories is not uniformly distributed among intersection movements, an unintended sample bias may be introduced when computing performance measures. This may affect signal retiming or capital investment opportunity identification algorithms.

An Incomplete Model of Disability: Discrepancies Between Performance-Based and Self-Reported Measures of Functioning.

Appropriate conceptualization and measurement of disability are critical for population-focused resource allocation and policy development. Self-reported and performance-based measures of functioning have been used to represent disability. Variation in environmental context or self-perception of ability may influence self-reports; however, performance-based measures that attempt to control environmental context may not accurately capture real-world aspects of functioning. This study examined the agreement between self-report and performance-based measures of functioning within 4 domains among older adults. Cross-sectional data from the 2021 National Health and Aging Trends Study was used. Self-reported and performance-based measures of functioning were assessed for vision, hearing, mobility, and memory domains. We examined the diagnostic characteristics of performance-based versus self-reported measures using sensitivity, specificity, and receiver operating characteristics curves. Differences in the agreement of these measures across sociodemographic groups were investigated using logistic regression. Among 2442 respondents 71 years and older (mean 78.5±5.3, 56% female participants), performance measures of hearing and mobility had high sensitivity (89% and 91%, respectively) and low/moderate specificity (36% and 63%, respectively). The sensitivity and specificity of vision measures were 71%. Memory measures had high specificity (89%) and low sensitivity (28%). Performance-based discrimination ranged from 0.59 (memory) to 0.78 (mobility). Agreement varied across sociodemographic factors. Performance measures diverge from self-reported functioning among older adults. Discordance may reveal opportunities for environmental intervention where participants' performance does not capture the full extent of barriers in their daily lives. Additional research is needed to investigate individual and environmental factors which could explain the observed differences.

Sex-stratified reference values for the life-space assessment in the Canadian longitudinal study on aging.

The Life-Space Assessment (LSA) can compliment traditional physical performance measures of mobility by accounting for the interaction between individuals and their environment. However, there are no studies that have generated percentile curves showing sex-stratified reference values in a large population-based sample of community-dwelling adults, making its interpretation difficult. Therefore, this study aimed to establish sex-stratified reference values for the LSA in middle-aged and older Canadians. Baseline data for participants aged 45-84years old from the Canadian Longitudinal Study on Aging (CLSA) were used (n = 22,154). Quantile regression was used to estimate specific percentiles, with age as the independent variable and LSA scores as the dependent variable. Models were run for the whole sample, then separately for males and females. The models were cross-validated to assess their reliability. CLSA inflation and analytic weights were applied. On average, the sample was 62.5 ± 10.0 y.o. (51.1% males), with a weighted mean LSA score of 89.2 ± 17.0. There was also a decrease in LSA scores with age, where scores were lower for older age groups compared to younger groups, and LSA scores were lower for females relative to males. Reference data will aid in interpreting, comparing, and making inferences related to LSA scores obtained in clinical and research settings for Canadian adults.

Investigating impacts of various operational conditions on fuel consumption and stop penalty at signalized intersections

When optimizing signals relevant traffic agencies adopt policies to either improve mobility performance measures (e.g., delay and stops), environmental aspects, or safety of signalized intersections. One of such policies, mainly implemented through so-called Performance Index (PI), advocates that reduction of excess fuel consumption (FC) should be achieved by minimizing the PI - a linear combination of delays and stops. The key factor of such a PI is the stop penalty “K”, which represents a weighting factor, or a stop equivalency measured in seconds of delay. In the contemporary signal optimization practice, this K is given a constant value (e.g., 10 seconds) and it is not recognized as a parameter that is dependent on various operational conditions. This study challenges that common view and presents a methodology to derive the K factor and investigate impacts of various operational conditions (e.g., cruising speed) on the K value. The study uses traffic simulation model coupled with a modal fuel consumption and emission model to investigate second-by-second FC during stopping events at a signalized intersection. The experiments are performed on a hypothetical, yet realistic, intersection under several operational scenarios. The findings show that the K varies significantly with all the investigated operational conditions. More importantly, results indicate that the K factor should be much larger than used by current signal timing practices. The implications of these findings may lead to significant changes in current polices for signal timing optimization. Future research shall validate these findings with second-by-second vehicle trajectory and FC data from the field.

Traffic Signal Optimization to Improve Sustainability: A Literature Review

Optimizing traffic signals to improve traffic progression relies on minimizing mobility performance measures (e.g., delays and stops). However, delay and stop minimizations do not necessarily lead to minimal sustainability measures (e.g., fuel consumption and emissions). For that reason, researchers have focused, for decades, on integrating traffic models, signal optimization models, and fuel consumption and emissions models to minimize sustainability metrics while keeping acceptable levels of mobility metrics. Therefore, this paper reviews, classifies, and analyzes studies found in the literature regarding optimizing sustainable traffic signals. This paper provides researchers with a good starting point to further develop solutions which can address sustainable traffic control. To achieve that, this study details the most notable sustainable signal timing optimization studies from six perspectives: traffic models, fuel consumption and emissions models, optimization methods, objective functions, operating conditions, and reported sustainability savings. Outcomes of this research show that the previous studies deployed many combinations of elements from the six-perspective mentioned above, leading to a wide range of fuel consumption and emissions savings. The study also concludes that the available fuel consumption and emissions models are relatively old. Hence, future research is needed to develop new fuel consumption and emissions models based on recently collected data.

Measurement Properties of Remotely or Self-Administered Lower Extremity Mobility Performance Measures in Adults: A Systematic Review.

For individuals who face barriers to care assessment, there is a need for remote administration or self-administration of physical performance measures that assess mobility to determine current functional status and to monitor and predict future changes in functional status. The primary purpose of this review is to evaluate the available measurement properties of scores for remotely or self-administered lower extremity mobility performance measures in adults. This review also outlines the test procedures and population suitability of these measures. Data sources were Ovid MEDLINE, Ovid Embase, EBSCOhost CINAHL, Ovid AMED, and Cochrane CENTRAL-which were searched from inception to January 26, 2021-and the reference lists of relevant studies. Two individuals independently screened studies that assessed at least 1 prespecified measurement property of scores for a remote and/or self-administered lower extremity physical performance measure assessing mobility in an adult population. Two individuals independently extracted data on study characteristics, measurement properties, feasibility, and interpretability using piloted extraction forms. The COSMIN (COnsensus-based Standards for the selection of health Measurement INstruments) Risk of Bias tool was used to assess methodological quality. Data were qualitatively summarized, and results were compared against COSMIN's criteria for good measurement properties. Level of evidence was determined using COSMIN's modified GRADE approach. Fourteen studies detailing 19 outcome measures were included. Many studies displayed "sufficient" measurement properties based on COSMIN's criteria; however, risk of bias for most of the included studies was rated adequate or doubtful. Clinicians and researchers can consider the measurement properties of scores and feasibility of different approaches presented in this review when determining how to assess or monitor mobility in adult populations. Assessing mobility via remote or self-administered physical performance measures in adult populations appears to be feasible using a variety of methods including simple tools (chair, stopwatch), videoconferencing, and smartphone applications. This strategy may be particularly valuable for self-management of chronic conditions and decreasing barriers to accessing care.

Effects of Autonomous Driving Behavior on Intersection Performance and Safety in the Presence of White Phase for Mixed-Autonomy Traffic Stream

This paper studies the effects of different autonomous driving behaviors on an isolated intersection’s safety and mobility performance measures in a mixed-autonomy environment. The movement of vehicles through the intersection is controlled by green, red, and “white” signal indications. Traffic operations during green and red signals are identical to a typical intersection. However, in the presence of the white phase, connected human-driven vehicles (CHVs) should follow connected and autonomous vehicles (CAVs) to pass the intersection safely. Three levels of driving aggressiveness for CAVs are considered: (1) cautious behavior, (2) normal behavior, and (3) aggressive behavior. The mobility and safety impacts of these CAV behaviors are studied based on different CAV market penetration rates and demand levels. The results indicate that a more aggressive CAV driving behavior leads to a lower average delay while increasing the average number of stops for CAVs. Additionally, a more aggressive CAV driving behavior leads to more frequent activation of the white phase that contributes to significant reduction in the speed variance. Moreover, the total number of rear-end near-collision observations with a time to collision of less than 10 s decreases as the CAV penetration rate and aggressiveness level increase. The main reason for this observation is that aggressive CAVs have higher acceleration and lower deceleration values and, therefore, have more flexibility to avoid a crash.

Evaluation of Race as a Predictor of Fear of Falling in Black Older Adults

Fear of falling (FOF) is a common issue and health concern reported by adults 65 years of age and older.There is mixed evidence about potential disparity in fall incident rates due to race and FOF, and it is unclear if and under what circumstance falls rates and risks differ by racial ethnicity. The purpose of this study is to determine if race predicts fear of falling in older adults at greater risk for falls; and to examine the relationship between activities of daily living (ADL) and mobility performance measures with FOF. A cross-sectional observational study was used to examine predictors of FOF among community dwelling-older adults using data from two longitudinal randomized clinical trials (RCT). Participants (N=259) had a mean age of 75.7 ±7.4, 78.8% female, 80.64% Black, and 77.03% White or Other, with ≥ 1 fall in the last 12 months. Subjects completed a demographic profile; the Tinetti and Short Falls Efficacy Scale to assess FOF; and activities of daily living (ADL) and mobility performance scales to assess function. The chi square analysis revealed Black older adults were two times more likely to report FOF (OR = 2.17, 95% CI = 1.14, 4.15; p=.05) in comparison to White older adults. The regression analysis demonstrated that race is a significant factor to predict FOF (OR = .67, 95% CI = 1.21, 3.24; p=.05); and the descriptive analysis revealed significantly worse ADL and mobility function scores within the high FOF group.

Physical performance measures in older women with urinary incontinence: pelvic floor disorder or geriatric syndrome?

Objective:To evaluate physical performance measures of mobility and functional impairments and assess their association with urinary incontinence (UI) severity and impact on quality of life among older women with UI.Methods:In a cross-sectional pilot study, 20 women aged ≥ 70 years with UI completed UI questionnaires (Global Impression of Severity, Incontinence Impact Questionnaire (IIQ-7)) and functional status evaluation. Functional status evaluation included the Modified Physical Performance Test (MPPT; range 0–36), Short Physical Performance Battery (SPPB; range 0–12), and other physical performance measures (e.g., Timed Up and Go [TUG]). MPPT and SPPB scores <32 and <10, respectively, indicated impaired mobility and function. Descriptive statistics and spearman correlation coefficients evaluated study variables and associations between UI and physical performance measures.Results:Women were 76.6±4.7 years old with mean body mass index 33.5±9.0 kg/m2. Mixed UI was the most prevalent (n=17; 85%), and 14 (70%) participants rated their UI as moderate or severe. Low MPPT (<32) and SPPB (<10) scores were present in 65% (n=13) and 35% (n=7) of participants, respectively. Lower MPPT score (r=−0.46; P=0.04) and worse TUG performance (r=0.50; P=0.03) were associated with greater UI impact on quality of life based on IIQ-7. SPPB did not correlate (P>0.05) with UI measures.Conclusions:Mobility and functional impairments are common among older women with UI. Associations between MPPT score, TUG performance with UI impact on quality of life suggest these physical performance measures could be markers of mobility and functional impairments in future research on UI in older women.

Continuous monitoring of mobility performance trajectory in patients receiving chemotherapy.

e14104 Background: Accurate performance status (PS) assessment is important for chemotherapy decisions, but current tools such as the Eastern Cooperative Oncology Group (ECOG) PS assessment are subjective, static, and prone to inter-observer and recall biases. Continuous patient monitoring technology can enhance PS assessment by providing an objective and dynamic measurement of mobility performance (MP), defined as mobility in real-life situations. This study examined the feasibility of a pendant sensor to continuously track MP during a 4-week period of chemotherapy. Methods: Patients on chemotherapy were recruited from a single center. Patients were asked to continuously wear a water-resistant pendant sensor (PAMSys, Biosensics, USA) for 4-weeks during the day and night. Patients completed psychosocial surveys (cognitive, depression, and fatigue) and a technology acceptance survey measured on a Likert scale from 1 (strongly disagree) to 5 (strongly agree). Chart review was completed for demographics, medical history, and baseline ECOG PS. Using a validated algorithm, postures (lying and sitting postures: LSP) and walking parameters (cadence, longest walking bout, total steps per day) were extracted from the pendant. We also calculated percent change from baseline activity to the lowest activity level during the 4-week period. To determine clinically meaningful digital biomarkers, we compared these MP measures between two groups: ECOG 0 or ECOG ≥1. Results: Fifteen patients (median age 68), with either a solid (n = 14) or hematologic (n = 1) malignancy, stages II-IV, with ECOG 0 (n = 7) and ECOG ≥1 (n = 8) were evaluated. Baseline psychosocial parameters were not significantly different. ECOG ≥1 tend to have poorer baseline walking compared to ECOG 0 with the largest effect size observed for cadence (79.2 ± 10.0 vs 73.3±3.7, Cohen’s d effect size d = 0.78). The percentage of MP decline was higher in ECOG 0 compared to ECOG ≥1 (89.0±22.9% vs 79.9±34.5%). None of the observed trends reached statistical significance. Patients reported that the pendant was comfortable to wear (4.9±0.30) and did not interfere with activities (4.9±0.25). Conclusions: This study showed the feasibility of a pendant sensor to continuously monitor MP and its trajectory during chemotherapy. Results suggest continuous MP monitoring may provide objective information to enhance PS assessment. Larger studies are needed to confirm statistical significance of digital MP metrics and its potential effect on clinical decisions such as dose reduction, rehabilitation, and palliative care.

Yoga improves balance, mobility, and perceived occupational performance in adults with chronic brain injury: A preliminary investigation

Background and purposeThis was a preliminary investigation to investigate potential benefits of group yoga, as past work has indicated that one-on-one yoga can improve functional deficits in adults with brain injury. Materials and methodsParticipants served as their own controls. Nine participants with chronic brain injury were recruited, and seven (four female) completed the study. Performance measures of balance and mobility and self-reported measures of balance confidence, pain, and occupational performance and satisfaction were used. Data were collected 3 times: baseline (study onset), pre-yoga (after an 8-week no-contact period), and post-yoga (after 8 weeks of yoga). Group yoga was led by a yoga instructor/occupational therapist, and sessions lasted 1 h and occurred twice a week. ResultsNo participants withdrew due to adverse effects from yoga. There were no significant changes between baseline and pre-yoga. Significant improvement was observed post-yoga in balance (p = 0.05), mobility (p = 0.03), and self-reported occupational performance (p = 0.04). ConclusionWe observed significant improvements in balance, mobility, and self-reported occupational performance in adults with chronic brain injury.

Driver Behavior Models for Heavy Vehicles and Passenger Cars at a Work Zone

Traffic impact assessment is a key step in the process of work zone planning and scheduling for transportation agencies. Microscopic traffic simulation models enable transportation agencies to conduct detailed analyses of work zone mobility performance measures during the planning and scheduling process. However, traffic simulation results are valid only when the simulation model is calibrated to replicate driver behavior that is observed in the field. Few studies have provided guidance on the calibration of traffic simulation models at work zones and have offered driver behavior parameters that reproduce capacity values that are observed in the field. This paper contributes to existing knowledge of work zone simulation by providing separate driver behavior model parameters for heavy vehicles and passenger vehicles. The driver behavior parameters replicate the flow and speed at the work zone taper and at roadway segments upstream of the work zone. A particle swarm optimization framework is proposed to improve the efficiency of the calibration process. The desired time headway was found to be 2.31 seconds for heavy vehicles and 1.53 seconds for passenger cars. The longitudinal following threshold was found to be 17.64 meters for heavy vehicles and 11.70 meters for passenger cars. The proposed parameters were tested against field data that had not previously been used in the calibration of driver behavior models. The average absolute relative error for flow rate at the taper was 10% and the mean absolute error was 54 veh/h/ln. The GEH statistic for the validation dataset was 1.48.

Measuring mobile broadband performance in Nigeria: 2G and 3G

With increase in broadband penetration rate in Nigeria there is very little known customer-centric mobile broadband performance analysis in the country, despite the inherent advantages associated with performance monitoring to regulators, operators, content-developers, and most especially the customers. There exists an information gap and customers are curious to know the Quality of Service (QoS) offered them. This paper presents a host and crowdsourced based approach to mobile broadband performance metric measurement and evaluation. A mobile broadband performance measurement application (MBPerf) was developed using Java and Extensible Markup Language (XML) and installed on volunteers’ Android Smartphones to measure and collect data relating to 4 (four) QoS metrics – download and upload speeds, latency and DNS (Domain Name Service) lookup; and user data such as mobile phone information, network information, and location information. Measurements were taken for a period of 3 months within Akure and Ibadan metropolis from the 4 major MNOs’ (MNO-A, MNO-B, MNO-C and MNO-D) networks in Nigeria. Data was retrieved from he cloud, pre-processed, sorted and analysed using Microsoft Excel version 13 and SPSS (Statistical Package for the Social Sciences) Statistics 19. Findings reveal that 3G users are not getting the industry set speeds. They get about 10% below the lower limit of the benchmark (500 kilobits per second). However, 2G users get a better deal of about 61% above the lower limit of the benchmark (100 kilobits per second). It was inferred that network performance is highly unpredictable and variable during the day (between 8am and 5pm) but greatly improves at the early hours of the morning (between 12am to 6am) with a difference of about 69% between the peak and worst performance. The study indicates that performance deteriorates at peak times (between 7pm and 11pm). Lastly the DNS performance analysis suggests that the MNOs’ DNS servers operate effectively and do not add significant delay to end users’ queries. Keywords: Mobile broadband performance, Quality of Service (QoS), crowdsourcing, MBPerf application, hostbased

Intraclass Correlation Coefficients for Planning Cluster Randomized Trials in Community-Dwelling Older Adults.

Objectives: With the emerging trends, more cluster randomized trials will be conducted in older adults, where facilities are randomized rather than individuals. Similarity of individuals from a facility (intraclass correlation coefficient/ICC) plays a critical role, but not readily available. We document ICCs for measures commonly used in community-dwelling older adults and discuss implications. Method: Secondary analysis of a range of baseline measures from the On the Move cluster randomized trial, whose ICCs were computed using a linear mixed model. Results: Self-reported disability measures related to facility characteristics and sense of community had the greatest ICCs (>0.10), while mobility performance measures had 0.05 to 0.10, and cognitive measure 0.11. Discussion: The ICCs for measures commonly used in older adults are of a sufficient magnitude to have a substantial impact on planned sample size of a study and credibility of results, and should be taken into consideration in study planning and data analysis.

Performance of Real-world Functional Tasks Using an Updated Oral Electronic Vision Device in Persons Blinded by Trauma.

The purpose of this study was to evaluate the impact of the BrainPort Vision Pro on real-world functional task performance in persons who are profoundly blind (light perception or worse) due to traumatic injury (ocular or cortical). This was a prospective, within-subjects, repeated-measures study. Participants received ten hours of device training and were required to use the device independently for 1 year. Functional performance measures of object identification, orientation and mobility, word identification, and environmental awareness were assessed at baseline, post-device training, and quarterly throughout the year. Seventeen profoundly blind adults were enrolled in the study. No clinically significant device-related adverse events were reported, demonstrating minimal risks associated with the BrainPort Vision Pro. None of the participants could successfully perform any of the functional tasks at baseline, without the device. After 1 year of independent device use, all participants could identify objects, and 41% identified words beyond chance level while using the device. Forty-one percent of participants could locate a sign, 94% followed a line without veering off, 71% avoided obstacles, 71% walked through a doorway without collision, 100% of participants recognized a door, and 71% identified a window. Results demonstrate significant improvements in real-world functional task performance in skill areas important to everyday life. The BrainPort Vision Pro offers a nonsurgical method for improving visual function in persons blinded by trauma. The device can enhance independence and support the successful integration of profoundly blind persons, including veterans and returning service members, into community life.

Age, Mobility Performance, and Physical Activity in Prostate Cancer Patients Undergoing Prolonged Androgen Deprivation Therapy

Androgen deprivation therapy (ADT) is a foundation of treatment for men with prostate cancer (PCa). However, ADT is accompanied by adverse effects that increase risk of functional decline. Although some clinical observations suggest that ADT may have a greater impact upon functional status among aged men, empirical evidence addressing age-related differences in the trajectory of adverse effects of prolonged ADT remains limited. PURPOSE: The purpose of the present pilot study was to explore differences in change in mobility performance and physical activity (PA) across 6 months among 3 different age cohorts of PCa patients undergoing ADT. METHODS: A total of 44 PC patients undergoing prolonged ADT (>6 months of treatment) were classified into 1 of 3 age cohorts: 55-64 (n=13); 65-74 (n=19); and 75+ years of age (n=12). Measures of mobility performance (400M Walk) and objectively-determined PA were obtained from men at baseline and 6 month follow-up assessments. RESULTS: Results of 3 (Age) x 2 (Time) ANOVA analysis demonstrated a significant Age main effect for mobility performance (p < .05) while the Age main effect for PA approached significance (p < .06). Post hoc analysis revealed patients in the youngest group had more favorable mobility performance relative to the middle (d = -.71) or oldest (d = -1.04) age groups and patients in the oldest group were accruing less objectively-determined PA relative to the middle (d = .65) or youngest (d = .92) age groups. However, the Age x Time interaction was not significant for mobility performance (p < .38) or PA (p < .28) indicating no differences in the trajectory of change were observed for either outcome as a function of age across time. CONCLUSIONS: This study provides some of the first preliminary evidence examining potential age-related differences in the trajectory of change in physical function and PA in PCa patients on ADT. Findings revealed that although well-established, anticipated age differences in mobility performance and PA were observed, no age-related differences in the trajectory of change in functional decline or PA emerged among PCa patients undergoing prolonged ADT.

Concurrent Validity of Two Gait Performance Measures in Children with Neuromotor Disorders

ABSTRACTAims: To investigate the concurrent validity of two mobility performance measures, the Functional Mobility Scale (FMS) and the Gillette Functional Assessment Questionnaire – walking scale (FAQ) in an inpatient pediatric neurorehabilitation setting. Methods: Cross-sectional data were collected on 71 children (mean age 12.7 years) with neuromotor gait impairments who participated in an inpatient rehabilitation program to evaluate aspects of concurrent validity of the FMS and FAQ. Physiotherapists independently performed ratings. Comparator instruments included the walking item of the Functional Independence Measure for children, 10-m and 6-minute walking tests, and Gross Motor Function Measure-88 dimension E. All tests were completed within 7 days. Spearman correlation coefficients were calculated to test a priori formulated hypotheses regarding the strength and direction of the measures relationships. Results: The children had a broad spectrum of mobility levels, including all levels of FMS and levels 2–10 of FAQ. Spearman correlation coefficients with comparator measures varied between 0.58–0.79 for the FMS and 0.69–0.73 for the FAQ. Hypotheses concerning correlation strengths and directions were met for FMS and FAQ. Conclusions: The findings demonstrate that the FMS and FAQ are valid to evaluate functional mobility in pediatric inpatient neurorehabilitation.

Do Performance Measures of Strength, Balance, and Mobility Predict Quality of Life and Community Reintegration After Stroke?

ObjectiveTo investigate the extent to which physical performance measures of strength, balance, and mobility taken at discharge from inpatient stroke rehabilitation can predict health-related quality of life (HRQoL) and community reintegration after 6 months. DesignLongitudinal study. SettingUniversity laboratory. ParticipantsAdults (N=75) recruited within 1 month of discharge home from inpatient stroke rehabilitation. InterventionsNot applicable. Main Outcome Measures36-Item Short Form Health Survey (SF-36) for HRQoL and Subjective Index of Physical and Social Outcome (SIPSO) for community reintegration. Physical performance measures were the 6-minute walk test, timed Up and Go (TUG) test, Berg Balance Scale, Community Balance and Mobility Scale, and isokinetic torque and power of hip, knee, and ankle on the paretic and nonparetic sides. Other prognostic variables included age, sex, stroke type and location, comorbidities, and motor FIM score. ResultsSeparate stepwise linear regressions were performed using the SF-36 and SIPSO as dependent variables. The total paretic lower limb torque and 6-minute walk test predicted the SF-36 Physical Component Summary (adjusted R2=.30). The total paretic lower limb torque and TUG test predicted the SIPSO physical component (adjusted R2=.47). The total paretic lower limb torque significantly predicted the SF-36 Mental Component Summary, but the adjusted R2 was low (.06). Similarly, the TUG test significantly predicted the SIPSO social component, but again the adjusted R2 was low (.09). ConclusionsMeasures of physical performance including muscle strength and mobility at discharge can partially predict HRQoL and community reintegration 6 months later. Further research is necessary for more accurate predictions.

Work Zone Impact Assessment Methods and Applications

Two work zone impact assessment methods were developed and their applicability was illustrated with data from recent construction projects on the I-35 Central Texas corridor. The first method was developed for postevent analyses of the impacts of freeway construction activities, incidents, and special events. The impacts were evaluated in terms of travel times and delay. An interval estimate for maximum queue length was also provided. Travel times and speeds were obtained by Bluetooth address matching. The method has also been used for determining work zone mobility performance measures, verifying the suitability of queue warning systems, and providing feedback for future deployment decisions. Based on more than 3 years’ experience with the analysis of impacts of road construction and maintenance projects as well as some major incidents on the I-35 corridor, the Bluetooth-based postevent closure analysis tool has proved to be very cost-effective. The second method was developed for determining the best closure schedule and start time for planned work zone lane closures. The best closure start time is the one that is expected to create the shortest queue lengths and has the least negative impact on travelers. The required input includes historical traffic volumes at a point upstream of the planned lane closure and estimated work zone capacity. The work zone capacity can vary over the duration of the work zone. The method runs input–output analysis in a dual-loop framework to analyze the impact of all available closure schedule scenarios and selects the best closure start time with the shortest expected queues.

Survey of Research for Performance Measurement of Mobile Manipulators.

This survey provides the basis for developing research in the area of mobile manipulator performance measurement, an area that has relatively few research articles when compared to other mobile manipulator research areas. The survey provides a literature review of mobile manipulator research with examples of experimental applications. The survey also provides an extensive list of planning and control references as this has been the major research focus for mobile manipulators which factors into performance measurement of the system. The survey then reviews performance metrics considered for mobile robots, robot arms, and mobile manipulators and the systems that measure their performance, including machine tool measurement systems through dynamic motion tracking systems. Lastly, the survey includes a section on research that has occurred for performance measurement of robots, mobile robots, and mobile manipulators beginning with calibration, standards, and mobile manipulator artifacts that are being considered for evaluation of mobile manipulator performance.