scholarly journals NOx and CO Fluctuations in a Busy Street Canyon

Environments ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 137
Author(s):  
Peter Brimblecombe ◽  
Meng-Yuan Chu ◽  
Chun-Ho Liu ◽  
Zhi Ning
Keyword(s):  
Signal Timing ◽  
Vehicle Speed ◽  
High Concentration ◽  
The Road ◽  
Wind Speeds ◽  
Pollutant Concentrations ◽  
Guideline Value ◽  
Busy Street ◽  
Traffic Signal Timing ◽  
Cyclic Changes

Busy street canyons can have a large flow of vehicles and reduced air exchange and wind speeds at street level, exposing pedestrians to high pollutant concentrations. The airflow tended to move with vehicles along the canyon and the 1-s concentrations of NO, NO2 and CO were highly skewed close to the road and more normally distributed at sensors some metres above the road. The pollutants were more autocorrelated at these elevated sensors, suggesting a less variable concentration away from traffic in the areas of low turbulence. The kerbside concentrations also showed cyclic changes approximating nearby traffic signal timing. The cross-correlation between the concentration measurements suggested that the variation moved at vehicle speed along the canyon, but slower vertically. The concentrations of NOx and CO were slightly higher at wind speeds of under a metre per second. The local ozone concentrations had little effect on the proportion of NOx present as NO2. Pedestrians on the roadside would be unlikely to exceed the USEPA hourly guideline value for NO2 of 100 ppb. Across the campaign period, 100 individual minutes exceeded the guidelines, though the effect of short-term, high-concentration exposures is not well understood. Tram stops at the carriageway divider are places where longer exposures to higher levels of traffic-associated pollutants are possible.

scholarly journals Traffic Signal Optimization and Vehicle Speed Control at Signalized Intersection

2020 ◽  
pp. 542-547
Author(s):  
S. R. Karthiga ◽  
G. Ramya ◽  
M. Ramya
Keyword(s):  
Arrival Time ◽  
Traffic Signal ◽  
Signalized Intersection ◽  
Traffic Signal Control ◽  
Signal Timing ◽  
Vehicle Speed ◽  
Speed Optimization ◽  
Total Travel Time ◽  
Traffic Signal Timing ◽  
Engine Power

The aim of this project is to promote the significant improvement of transportation efficiency and fuel economy by the cooperative method of traffic signal control and vehicle speed optimization. It formulates the optimal traffic signal timing and vehicles arrival time to minimize the total travel time of all vehicle and to optimize the engine power to minimize the fuel consumption of individual vehicles.

scholarly journals Travel Time Reliability-Based Signal Timing Optimization for Urban Road Traffic Network Control

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Zhengfeng Ma ◽  
Darong Huang ◽  
Changguang Li ◽  
Jianhua Guo
Keyword(s):  
Travel Time ◽  
Optimization Model ◽  
Road Traffic ◽  
Signal Timing ◽  
Traffic Network ◽  
Travel Time Reliability ◽  
Timing Optimization ◽  
The Road ◽  
Signal Timing Optimization ◽  
Traffic Signal Timing

Due to increasing traffic demand, many metropolitan areas are experiencing extensive traffic congestion, which demands for efficient traffic signal timing and optimization. However, conventional efficiency measure-based signal optimization cannot handle the ubiquitous uncertainty in the road networks, demanding for the incorporation of reliability measures into signal optimization, which is still in its early stage. Therefore, targeting this issue, based on the recent studies on recognizing travel time reliability (TRR) as an important reliability measure of road networks, a travel time reliability-based urban road traffic network signal timing optimization model is proposed in this paper, with the objective function to optimize a TTR measure, i.e., buffer time index. The proposed optimization model is solved using the heuristic particle swarm optimization approach. A case study is conducted using microscopic traffic simulation for a road network in the City of Nanjing, China. Results demonstrate that the proposed optimization model can improve travel time reliability of the road traffic network and the efficiency of the road traffic network as well. Future studies are recommended to expand the integration of travel time reliability into traffic signal timing optimization.

scholarly journals PENGARUH BOREDOM PRONENESS DAN LOCUS OF CONTROL TERHADAP KECEPATAN SAAT MENGEMUDI DI JABODETABEK

2021 ◽  
Vol 4 (2) ◽  
pp. 397
Author(s):  
Gavriel Ganesia Prajitna ◽  
Leksmono Suryo Putranto
Keyword(s):  
Structural Equation Modeling ◽  
Locus Of Control ◽  
Structural Equation ◽  
Good Control ◽  
Equation Modeling ◽  
Vehicle Speed ◽  
High Concentration ◽  
The Road ◽  
Boredom Proneness ◽  
On The Road

Driving is an activity that contains a high risk such as loss, damage, loss, accidents and even death, so the drivers requires full attention with very high concentration. One of the causes of accidents experienced by some drivers is the result of several internal factors from the driver, one of the factors is boredom proneness. To be able to control all factors while driving, of course, good control skills are needed for the driver. One of the constructs that is able to explain this is the locus of control. In terms of driving on the road, drivers must also pay attention to personal safety by paying attention to vehicle speed. This research was conducted to determine the effect of locus control on boredom prone, boredom prone to speed, and control locus on speed. Data for research were obtained through online questionnaires. This research will be the method of Structural Equation Modeling (SEM). From the research results, it was found that the boredom proneness greatly affects a person's choice of speed. Meanwhile, the locus of control is a factor that slightly affects a person's speed selection. In addition, the locus of control is sufficient to affect a person's boredom proneness nature ABSTRAKMengemudi merupakan kegiatan yang mengandung resiko tinggi seperti kerugian, kerusakan, kehilangan, kecelakaan bahkan kematian, dengan demikian pengemudi membutuhkan perhatian penuh dengan konsentrasi sangat tinggi. Salah satu penyebab kecelakaan yang dialami beberapa pengemudi adalah akibat beberapa faktor internal dari pengemudi tersebut, salah satu faktor nya adalah rawan bosan. Untuk dapat mengontrol semua faktor ketika mengemudi, tentu dibutuhkan kemampuan kontrol yang baik pada pengemudi. Salah satu konstruk yang mampu menjelaskan hal tersebut yaitu lokus kendali. Dalam hal mengemudi di jalan, pengemudi juga harus memperhatikan keselamatan diri dengan memperhatikan kecepatan kendaraan. Penelitian ini dilakukan untuk mengetahui pengaruh lokus kendali terhadap rawan bosan, rawan bosan terhadap kecepatan, dan lokus kendali terhadap kecepatan. Data untuk penelitian didapatkan melalui kuesioner secara online. Penelitian ini akan Metode Structural Equation Modeling (SEM). Dari hasil penelitian didapatkan bahwa rawan bosan sangat mempengaruhi pilihan kecepatan seseorang. Sedangkan lokus kendali merupakan faktor yang sedikit mempengaruhi  pemilihan kecepatan seseorang. Selain itu lokus kendali cukup mempengaruhi sifat rawan bosan seseorang.

scholarly journals Smartphone monitoring of in-ambulance vibration and noise

2021 ◽  
pp. 095441192098599
Author(s):  
Tom Partridge ◽  
Lorelei Gherman ◽  
David Morris ◽  
Roger Light ◽  
Andrew Leslie ◽  
...  
Keyword(s):  
Transport Systems ◽  
Vertical Acceleration ◽  
Vehicle Speed ◽  
Noise Levels ◽  
The Road ◽  
Neonatal Transport ◽  
Mass Data ◽  
Transport Team ◽  
Vertical Accelerations ◽  
Noise Vibration

Transferring sick premature infants between hospitals increases the risk of severe brain injury, potentially linked to the excessive exposure to noise, vibration and driving-related accelerations. One method of reducing these levels may be to travel along smoother and quieter roads at an optimal speed, however this requires mass data on the effect of roads on the environment within ambulances. An app for the Android operating system has been developed for the purpose of recording vibration, noise levels, location and speed data during ambulance journeys. Smartphone accelerometers were calibrated using sinusoidal excitation and the microphones using calibrated pink noise. Four smartphones were provided to the local neonatal transport team and mounted on their neonatal transport systems to collect data. Repeatability of app recordings was assessed by comparing 37 journeys, made during the study period, along an 8.5 km single carriageway. The smartphones were found to have an accelerometer accurate to 5% up to 55 Hz and microphone accurate to 0.8 dB up to 80 dB. Use of the app was readily adopted by the neonatal transport team, recording more than 97,000 km of journeys in 1 year. To enable comparison between journeys, the 8.5 km route was split into 10 m segments. Interquartile ranges for vehicle speed, vertical acceleration and maximum noise level were consistent across all segments (within 0.99 m . s−1, 0.13 m · s−2 and 1.4 dB, respectively). Vertical accelerations registered were representative of the road surface. Noise levels correlated with vehicle speed. Android smartphones are a viable method of accurate mass data collection for this application. We now propose to utilise this approach to reduce potential harmful exposure, from vibration and noise, by routing ambulances along the most comfortable roads.

scholarly journals Cortical Activity Linked to Clocking in Deaf Adults: fNIRS Insights with Static and Animated Stimuli Presentation

2021 ◽  
Vol 11 (2) ◽  
pp. 196
Author(s):  
Sébastien Laurent ◽  
Laurence Paire-Ficout ◽  
Jean-Michel Boucheix ◽  
Stéphane Argon ◽  
Antonio Hidalgo-Muñoz
Keyword(s):  
Near Infrared ◽  
Brain Activity ◽  
Time Estimation ◽  
Cognitive Effort ◽  
Deaf People ◽  
Vehicle Speed ◽  
Neural Basis ◽  
Functional Near Infrared Spectroscopy ◽  
The Road ◽  
Deaf Adults

The question of the possible impact of deafness on temporal processing remains unanswered. Different findings, based on behavioral measures, show contradictory results. The goal of the present study is to analyze the brain activity underlying time estimation by using functional near infrared spectroscopy (fNIRS) techniques, which allow examination of the frontal, central and occipital cortical areas. A total of 37 participants (19 deaf) were recruited. The experimental task involved processing a road scene to determine whether the driver had time to safely execute a driving task, such as overtaking. The road scenes were presented in animated format, or in sequences of 3 static images showing the beginning, mid-point, and end of a situation. The latter presentation required a clocking mechanism to estimate the time between the samples to evaluate vehicle speed. The results show greater frontal region activity in deaf people, which suggests that more cognitive effort is needed to process these scenes. The central region, which is involved in clocking according to several studies, is particularly activated by the static presentation in deaf people during the estimation of time lapses. Exploration of the occipital region yielded no conclusive results. Our results on the frontal and central regions encourage further study of the neural basis of time processing and its links with auditory capacity.

scholarly journals Design of Road-Side Barriers to Mitigate Air Pollution near Roads

2021 ◽  
Vol 11 (5) ◽  
pp. 2391
Author(s):  
Jose I. Huertas ◽  
Javier E. Aguirre ◽  
Omar D. Lopez Mejia ◽  
Cristian H. Lopez
Keyword(s):  
Fluid Dynamics ◽  
Air Pollution ◽  
Computational Fluid Dynamics ◽  
Sulfur Hexafluoride ◽  
Computational Domain ◽  
Cfd Model ◽  
Near Surface ◽  
The Road ◽  
Pollutant Concentrations ◽  
Highly Correlated

The effects of using solid barriers on the dispersion of air pollutants emitted from the traffic of vehicles on roads located over flat areas were quantified, aiming to identify the geometry that maximizes the mitigation effect of air pollution near the road at the lowest barrier cost. Toward that end, a near road Computational Fluid Dynamics (NR-CFD) model that simulates the dispersion phenomena occurring in the near-surface atmosphere (<250 m high) in a small computational domain (<1 km long), via Computational Fluid Dynamics (CFD) was used. Results from the NR-CFD model were highly correlated (R2 > 0.96) with the sulfur hexafluoride (SF6) concentrations measured by the US-National Oceanic and Atmospheric Administration (US-NOAA) in 2008 downwind a line source emission, for the case of a 6m near road solid straight barrier and for the case without any barrier. Then, the effects of different geometries, sizes, and locations were considered. Results showed that, under all barrier configurations, the normalized pollutant concentrations downwind the barrier are highly correlated (R2 > 0.86) to the concentrations observed without barrier. The best cost-effective configuration was observed with a quarter-ellipse barrier geometry with a height equivalent to 15% of the road width and located at the road edge, where the pollutant concentrations were 76% lower than the ones observed without any barrier.

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