Influence of solar glare intensity on vehicular speed variance

2021 ◽  
Vol 20 ◽  
pp. 101020
Author(s):  
Boram Woo ◽  
Hoyong Kim ◽  
Jisook Kim ◽  
Hojong Baik ◽  
Hoe Kyoung Kim
Keyword(s):  
PEDIATRICS ◽  
1996 ◽  
Vol 98 (6) ◽  
pp. 1096-1103
Author(s):  
Phyllis F. Agran ◽  
Diane G. Winn ◽  
Craig L. Anderson ◽  
Cecile Tran ◽  
Celeste P. Del Valle

Objective. To identify environmental risk factors on residential streets for pediatric pedestrian injuries. Method. The sample consisted of 39 Latino children 0 to 14 years of age injured as pedestrians on a street in the same block as their home and 62 randomly selected neighborhood control subjects matched to the case by city, age or year of birth, ethnicity, and gender. The cases were identified from a population-based hospital and coroner's office surveillance system established in north-central Orange County, CA. Neighborhood assessments were performed from 3:45 PM to 5 PM, a fairly active time for young pedestrians. The cases were compared with the controls using conditional logistic regressions; in this study design, the odds ratios were interpreted as estimates of the incidence rate ratios. Results. Children living in a multifamily residence had an incidence of injury greater than that of children living in single-family residence on a single lot (odds ratio [OR] 3.1, 95% confidence interval [CI] 1.3-7.6). The ORs in the highest category were several times those in the lowest category for both parked vehicles (OR 9.6, 95% CI 2.6-36) and total number of pedestrians observed (OR 4.7, 95% CI 1.4-16). Vehicle parking, total pedestrians, vehicular traffic volume, and speed were examined in a multivariate model. The association of vehicles parked on the street with pedestrian injury risk remained significant. Unlike the crude results, progressively greater vehicular speed was associated with a marked increase in risk. Progressively higher vehicular traffic volume was associated with a progressively lower adjusted OR. Conclusion. The results of this analysis would indicate that residential streets with a high proportion of multifamily residences, over 50% of the curb occupied with parked vehicles, and a large number of pedestrians observed in unenclosed areas should receive high priority for intervention programs to reduce pediatric pedestrian injuries. The analysis suggests that on these streets, measures to reduce the amount of street parking (thus increasing visibility) and reductions in vehicular speed should be considered to decrease pedestrian injuries.


2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Song Yang ◽  
Bing Qi ◽  
Zhensheng Cao ◽  
Shaoqiang Zhang ◽  
Huailei Cheng ◽  
...  

The strain responses of asphalt pavement layer under vehicular loading are different from those under falling weight deflectometer (FWD) loading, due to the discrepancies between the two types of loadings. This research aims to evaluate and compare the asphalt layer responses under vehicular loading and FWD loadings. Two full-scale asphalt pavement structures, namely, flexible pavement and semirigid pavement, were constructed and instrumented with strain gauges. The strain responses of asphalt layers under vehicular and FWD loadings were measured and analyzed. Except for field measurements, the finite element (FE) models of the experimental pavements were established to simulate the pavement responses under a wide range of loading conditions. Field strain measurements indicate that the asphalt layer strain under vehicular loading increases with the rising temperature roughly in an exponential mode, while it decreases with the rising vehicular speed approximately linearly. The strain pulses in the asphalt layer generated by FWD loading are different from those induced by vehicular loading. The asphalt layer strains generated by FWD loading are close to those induced by low vehicular speed (35 km/h). The results from the FE model imply that the asphalt layer strains under FWD loading and vehicular loading are distributed similarly in the depth profile. For flexible pavement, the position of critical strain shifts gradually from the bottom of the asphalt layer to the mid-depth of the layer, as the temperature increases. For semirigid pavement, the position of critical strain is always located at the intermediate depth of the asphalt layer, regardless of temperatures.


2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Liuhui Zhao ◽  
Joyoung Lee ◽  
Steven Chien ◽  
Cheol Oh

A shockwave-based speed harmonization algorithm for the longitudinal movement of automated vehicles is presented in this paper. In the advent of Connected/Automated Vehicle (C/AV) environment, the proposed algorithm can be applied to capture instantaneous shockwaves constructed from vehicular speed profiles shared by individual equipped vehicles. With a continuous wavelet transform (CWT) method, the algorithm detects abnormal speed drops in real-time and optimizes speed to prevent the shockwave propagating to the upstream traffic. A traffic simulation model is calibrated to evaluate the applicability and efficiency of the proposed algorithm. Based on 100% C/AV market penetration, the simulation results show that the CWT-based algorithm accurately detects abnormal speed drops. With the improved accuracy of abnormal speed drop detection, the simulation results also demonstrate that the congestion can be mitigated by reducing travel time and delay up to approximately 9% and 18%, respectively. It is also found that the shockwave caused by nonrecurrent congestion is quickly dissipated even with low market penetration.


Author(s):  
Gayathri Chandrasekaran ◽  
Tam Vu ◽  
Alexander Varshavsky ◽  
Marco Gruteser ◽  
Richard P. Martin ◽  
...  
Keyword(s):  

Atmosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1372
Author(s):  
Felipe Cifuentes ◽  
Carlos M. González ◽  
Erika M. Trejos ◽  
Luis D. López ◽  
Francisco J. Sandoval ◽  
...  

Vehicular emissions are a predominant source of pollution in urban environments. However, inherent complexities of vehicular behavior are sources of uncertainties in emission inventories (EIs). We compare bottom-up and top-down approaches for estimating road transport EIs in Manizales, Colombia. The EIs were estimated using a COPERT model, and results from both approaches were also compared with the official top-down EI (estimated from IVE methodology). The transportation model PTV-VISUM was used for obtaining specific activity information (traffic volumes, vehicular speed) in bottom-up estimation. Results from COPERT showed lower emissions from the top-down approach than from the bottom-up approach, mainly for NMVOC (−28%), PM10 (−26%), and CO (−23%). Comparisons showed that COPERT estimated lower emissions than IVE, with higher differences than 40% for species such as PM10, NOX, and CH4. Furthermore, the WRF–Chem model was used to test the sensitivity of CO, O3, PM10, and PM2.5 predictions to the different EIs evaluated. All studied pollutants exhibited a strong sensitivity to the emission factors implemented in EIs. The COPERT/top-down was the EI that produced more significant errors. This work shows the importance of performing bottom-up EI to reduce the uncertainty regarding top-down activity data.


1975 ◽  
Vol 11 (4) ◽  
pp. 473-478 ◽  
Author(s):  
Tohru IDOGAWA ◽  
Masahiro WATARI ◽  
Ryoji OHBA ◽  
Nobukatsu TAKAI

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