scholarly journals Impact Assessment of Driver Distraction by Cellphone on Start-up Lost-time and Average Saturation Headway at Signalized Intersections Based on Vehicle Position in the Queue

2021 ◽  
Vol 49 (4) ◽  
pp. 359-368
Author(s):  
Nawaf Alshabibi
Keyword(s):  
Signalized Intersections ◽  
Signalized Intersection ◽  
Level Of Service ◽  
Total Delay ◽  
Main Hypothesis ◽  
Start Up ◽  
Lost Time ◽  
Vehicle Position ◽  
Secondary Hypothesis ◽  
The Impact

Cellphone usage has a significant impact on signalized intersections' capacity and level of service. This study investigated the impact of cellphone usage on signalized intersection capacity and level of service in Dammam Metropolitan Area, Saudi Arabia. The data included 183 useful cycles and 2407 start-up lost time and average saturation headway values at cycles with cellphone usage and cycles without cellphone usage at 24 signalized intersections. The main hypothesis of the study is that cellphone usage increases the start-up lost time at signalized intersection capacity. The secondary hypothesis is that cellphone usage increases the average saturation headway at signalized intersections. Normal distribution and z-test were conducted to assess whether there is a significant increase in average saturation headway and start-up lost time. The study found a significant increase in start-up lost time of about 0.7 seconds but found no significant increase in average saturation headway due to cellphone usage. Also, start-up lost time increases as vehicles of cellphone users get closer to the stop line of the signalized intersections. Thus, cellphone usage decreases the progression of 13 vehicles per hour due to a reduction in effective green time, increases total delay, and deteriorates the level of service. The study can assist transportation and traffic officials to optimize signal operation to mitigate the impact of cellphone usage and improve urban transportation.

Variations in Capacity at Signalized Intersections with Different Area Types

2000 ◽  
Vol 1710 (1) ◽  
pp. 199-204 ◽  
Author(s):  
Xuewen Le ◽  
Jian Lu ◽  
Edward A. Mierzejewski ◽  
Yanhu Zhou
Keyword(s):  
Signalized Intersections ◽  
Capacity Analysis ◽  
Adjustment Factor ◽  
Highway Capacity ◽  
Left Turn ◽  
Highway Capacity Manual ◽  
Central Florida ◽  
Start Up ◽  
Study Results ◽  
Lost Time

The capacity analysis procedure for signalized intersections included in the Highway Capacity Manual (HCM) needs to consider the area type of a given intersection. The area-type adjustment factor used in the procedure is based on conclusions from a limited number of studies. In addition, the procedure for using an area-type adjustment factor is not well defined in the HCM. A study undertaken in central Florida to study the effects of four different area types on the capacity of signalized intersections is summarized. These four area types include recreational, business, residential, and shopping. Study results indicated that differences in saturation headways among different area types were significant. The saturation headways observed in recreational areas were significantly higher than those in other areas for both left-turn and through movements. The through-movement saturation headways obtained in residential, shopping, and business areas were not significantly different. This study resulted in a new area-type adjustment factor of 0.92 for recreational areas, whereas the factor is 1.00 for other areas. Results in this study also indicated that the differences in start-up lost time among different area types were not significantly different. In addition, according to the results of the analysis, 75 percent of the yellow interval in undersaturated conditions and 35 percent of the yellow interval in oversaturated conditions were found to be unused and considered clearance lost time.

Effect of Bicycles on Capacity of Signalized Intersections

1998 ◽  
Vol 1646 (1) ◽  
pp. 87-95 ◽  
Author(s):  
D. Patrick Allen ◽  
Joseph E. Hummer ◽  
Nagui M. Rouphail ◽  
Joseph S. Milazzo
Keyword(s):  
Signalized Intersections ◽  
Signalized Intersection ◽  
Motor Vehicles ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Flow Adjustment ◽  
Conflict Zone ◽  
Pedestrian Traffic ◽  
Saturation Flow ◽  
The Impact

Although much is known about the operation of signalized intersections, little or no empirical research has been conducted regarding the effect of bicycles on signalized intersection capacity. The purpose of this study was to accurately quantify the effects of bicycles on signalized intersection capacity through the videotaping of several intersections that had significant bicycle traffic. Through the videotaping of intersections in Davis, California, and Gainesville, Florida, a relationship was determined between bicycle volumes and the percent of the green phase during which bicycle traffic occupies a conflict zone between bicycles and right-turning motor vehicles. It was also determined that one can ascertain the total net occupancy due to pedestrians and bicycles by taking the overlapping effects between bicycles and pedestrians into account. Using this total occupancy due to bicycles and pedestrians, one can calculate a saturation flow adjustment factor ( fRph) that reflects the reduction in saturation flow, and ultimately lane group capacity, for lane groups containing vehicles making permissive right turns in the presence of bicycles and pedestrians. The proposed procedure yields lower saturation flows and capacities than the current Highway Capacity Manual (HCM) procedure. In other words, on the basis of empirical data, when combined with pedestrian effects, the impact of bicycles on the saturation flow of lane groups containing right-turning vehicles is probably more detrimental than previously believed, and the capacities of intersections with significant bicycle and pedestrian traffic may be overestimated by using the current HCM procedures.

scholarly journals An Improvement of Three Leg Signalized Intersections in Duhok City Kurdistan-Iraq

2018 ◽  
Vol 7 (4) ◽  
pp. 87
Author(s):  
Baran R. Omer ◽  
Sherzad W. Khalid
Keyword(s):  
Cycle Time ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Level Of Service ◽  
Remarkable Improvement ◽  
Iraqi Kurdistan ◽  
Length Changes ◽  
Time Changes ◽  
Geometric Changes ◽  
The City

Nowadays, number of cars increases in Iraqi Kurdistan. Duhok is one of the Iraqi Kurdistan cities where an enormous increase in the number of cars and population is noticed during the last decade. Roads were been mended according to the 1970s plans where the city was small and number of cars was few. Although the city geographically is located in a hilly area and between two mountains, mending roads is a problem of area. Roads in the mentioned city are quite busy due to the high number of cars, traffic jams can be noticed in every corner of the city especially in signalized intersections. The level of service (LOS) in most of the signalized intersections is F or E. in order to lower the high (LOS), a three leg signalized intersection has been chosen to do an improvement on. During the study the number of the cars (Volume) have been enumerated in all lane groups and the results showed that the (LOS) was E in the intersection. As a result, some solutions have been provided according to the site area and the traffic flow. Solutions were geometric changes, cycle time changes or combination in both geometric and cycle time changes. According to the collected data, it was found that level of service was E for WB and SB and for EB was D. Based on data analysis it was found that LOS has not been improved when only one of the mentioned solutions is applied. In order to have the best improvement, the combination between geometric and cycle time length changes are applied. Analysis showed that there was a remarkable improvement in LOS and changed from E to D.

Operational Impact of Split Intersections

1997 ◽  
Vol 1579 (1) ◽  
pp. 73-78 ◽  
Author(s):  
Abishai Polus ◽  
Ronen Cohen
Keyword(s):  
Minimum Distance ◽  
Signalized Intersections ◽  
Left Turn ◽  
Suburban Areas ◽  
Advantages And Disadvantages ◽  
Minor Road ◽  
Lost Time ◽  
The Right ◽  
The Impact ◽  
Operational Impact

High volumes at urban and suburban intersections may cause considerable delay to vehicles during the peak periods, particularly when the left-turning volume is combined with high through volumes in both directions. The operational impact resulting from converting a major conventional cross intersection into two smaller signalized intersections is analyzed and evaluated. The two intersections are constructed along the minor road, allowing the left-turn movement from the major road to operate simultaneously with the through movement and to be stored in more lanes on the minor road. The general advantages and disadvantages of a split intersection are discussed. It is shown that the split increases capacity because of better efficiency resulting from ( a) the smaller geometry of each intersection, which reduces “lost time,” compared to the geometry of a single larger intersection, ( b) a reduction in the number of signal phases from four to three and an increase in the effective green time for all movements, and ( c) an increase in the number of lanes available for storage of the left-turn movement. It is also shown that delay is reduced, particularly when the flow is close to saturation. The impact of the cycle length and the left-turn volume is evaluated. Further analysis ascertains the minimum distance between the two smaller intersections under two scenarios: ( a) a minimum distance for storage of the left-turn movement and ( b) a longer distance to reduce delays and to allow for the simultaneous start of the green time for the through movements in the two intersections. It is concluded that the longer distance is feasible mainly for new intersections in suburban areas where the right of way is available.

Analysis on Capacity and LOS of Signalized Intersection in Slight Snowy Weather

2012 ◽  
Vol 209-211 ◽  
pp. 930-933 ◽  
Author(s):  
Chun Xiao Liu ◽  
Guo Zhu Cheng ◽  
Ya Ping Zhang
Keyword(s):  
Signalized Intersections ◽  
Signalized Intersection ◽  
Level Of Service ◽  
Line Method ◽  
Sunny Weather ◽  
American Standard ◽  
Operation Status ◽  
Traffic Operation ◽  
Stop Line

In order to evaluate traffic operation status of signalized intersection in slight snowy weather, it was studied that the influence of slight snow on capacity and level of service (LOS) of signalized intersection. Data of timing, vehicle’s starting loss time, saturated headway of straight vehicle and delay of one signalized intersections in sunny and slight snowy weather were observed by video method. Stop-line method was adopted to calculate the capacity of signalized intersection and LOS was evaluated by American standard. It showed that capacity of signalized intersection decreased by 7% and LOS declined one level in slight snowy weather compared with on sunny weather.

scholarly journals Capacity of Bicycle Platoon Flow at Two-Phase Signalized Intersection: a Case Analysis of Xi’an City

2011 ◽  
Vol 23 (3) ◽  
pp. 177-186 ◽  
Author(s):  
Yong-Gang Wang ◽  
Gang Wei ◽  
Xu Zhu ◽  
Yu-Long Pei
Keyword(s):  
Arrival Rate ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Pedestrian Flow ◽  
Two Phase ◽  
Signal Parameters ◽  
Capacity Model ◽  
Saturation Flow ◽  
The Impact ◽  
Xi’An City

Although much is known about the operation of signalized intersections, little or no empirical research has been conducted regarding bicycle capacity at these locations and the correspondent contributory factors. The purpose of this study is to accurately quantify the capacity of bikeway at signalized intersection through a fluid dispersion approach, and ultimately the lane group capacity. Using this total dispersion of bicycle flow, a relationship is also described between bicycle volume per hour and per unit width, signal parameters (length of signal cycle and green time), bicycle flow (arrival rate, density, moving velocity) and geometric intersection distance. Through the videotaping of four intersections that have significant bicycle traffic around Xiaozhai in Xi’an, China, it is ascertained that bicycle capacity varies linearly (but limited by an asymptote domain) associated with the adjustment of these parameters. The analytical results indicate that the impact saturation flow of lane groups containing right-turning vehicles and pedestrian flow at signalized intersections on bicycles is being underestimated. If this is the case, then capacity is being overestimated through the HCM 2000 capacity model and JJ37-90 approach and intersections are not being adequately designed, due to the neglect of conflict nature of mixed traffic arrivals in competing for space.

scholarly journals Acceptability of Countdown Signals at an Urban Signalized Intersection and their Influence on Drivers Behaviour

1970 ◽  
Vol 25 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Robert Rijavec ◽  
Jure Zakovšek ◽  
Tomaž Maher
Keyword(s):  
Traffic Flow ◽  
Field Test ◽  
Signalized Intersection ◽  
Test Results ◽  
Traffic Light ◽  
Light Phase ◽  
Detection Technology ◽  
Start Up ◽  
Lost Time ◽  
Violation Rate

There are different factors that affect driver’s behaviour at an urban signalized intersection. Complementary countdown signal heads can be used to inform the driver about the traffic light phase status. In the research presented in this paper, we explored how a countdown signal affects the driver’s reaction. We focused on the analysis of red/amber, red and amber running violations. We also observed and measured traffic flow start-up lost time and headway per cycle. Measurements took place in Ljubljana at a four-way intersection where two countdown signal heads are installed that face different directions. We used the “on-off-on” approach, using video surveillance and detection technology. According to the results of the investigative questionnaire, more than 84% of the surveyed drivers expressed positive opinion about the device. Analyses of field-test results have shown that the red and/or amber running violation rate is higher when the device is turned off. The results of the paper suggest that the countdown device had very little effect on the capacity of an urban signalized intersection.

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