Fuel Consumption and Traffic Emissions Evaluation of Mixed Traffic Flow with Connected Automated Vehicles at Multiple Traffic Scenarios

To analyze the impact of different proportions of connected automated vehicles (CAVs) on fuel consumption and traffic emissions, this paper studies fuel consumption and traffic emissions of mixed traffic flow with CAVs at different traffic scenarios. Firstly, the car-following modes and proportional relationship of vehicles in the mixed traffic flow are analyzed. On this basis, different car-following models are applied to capture the corresponding car-following modes. Then, Virginia Tech microscopic (VT-micro) model is adopted to calculate the instantaneous fuel consumption and traffic emissions. Finally, based on three typical traffic scenarios, a basic segment with bottleneck zone, ramp of the freeway, and signalized intersection, a simulation platform is built based on Python and SUMO to obtain vehicle trajectory data, and the fuel consumption and traffic emissions in different scenarios are obtained. The results show that (1) In different traffic scenarios, the application of CAVs can reduce fuel consumption and traffic emissions. The higher the penetration rate, the more significant the reduction in fuel consumption and traffic emissions. (2) In the three typical traffic scenarios, the advantages of CAVs are more evident in the signalized intersection. When the penetration rate of CAVs is 100%, the fuel consumption and traffic emissions reduction ratio is as high as 32%. It is noteworthy that the application of CAVs in urban transportation will significantly reduce fuel consumption and traffic emissions.

PERFORMANCE OF THREE ARMS SIGNALIZED INTERSECTION AT SALABENDA IN BOGOR REGENCY

<p>The increase in urban transportation in the 2000s era was very high. The use of motorized vehicles during the pandemic has decreased slightly with the government's ban on traveling out of town, including the 2020 homecoming and 2021 homecoming. Most people who travel are in the city center, including the city of Bogor and Bogor district. The travel patterns are very diverse, but most use public transportation and private transportation in addition to freight transportation with a fairly high intensity, especially at night. The purpose of this study was to obtain the LoS value at the signalized intersection of the three arms of the Salabenda intersection. The three-arm Salabenda intersection is the border between Bogor regency and the city of Bogor, so this intersection is one of the busiest and most densely populated intersections beside the Ciawi intersection in the north. The Salabenda intersection has become more congested with the opening of the Section IIIA Toll Road so that the traffic load shifts from Jl. KH. Sholeh Iskandar to this toll road, so that the intersection will have a higher traffic intensity. From the three observations and data collection in the field, it can be seen that in the afternoon it has a very high LoS, namely E. Followed by a LoS D level in the afternoon and in the morning LoS is still in the form of C. So it is still safe to use in the morning with a recommended level. The LoS E condition is a condition where the intersection has a degree of saturation of 0.926, which is almost close to 1, exacerbated by high side resistance activity.</p>

Efficiency Assessment of a Signalized Roundabout and a Traffic Intersection in Baghdad City

In Baghdad city, Iraq, the traffic volumes have rapidly grown during the last 15 years. Road networks need to reevaluate and decide if they are operating properly or not regarding the increase in the number of vehicles. Al-Jadriyah intersection (a four-leg signalized intersection) and Kamal Junblat Square (a multi-lane roundabout), which are two important intersections in Baghdad city with high traffic volumes, were selected to be reevaluated by the SIDRA package in this research. Traffic volume and vehicle movement data were abstracted from videotapes by the Smart Traffic Analyzer (STA) Software. The performance measures include delay and LOS. The analysis results by SIDRA Intersection 8.0.1 show that the performance of the roundabout is better than the signalized intersection but experiences high delay, and low LOS. Therefore, alternatives are proposed to improve the performance for current and future traffic volumes with low-medium delays.

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

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.

Comparative Study of Operational Performance between Roundabout and Signalized Intersection Using Sidra Software: A Case Study of Addis Ababa City

Traffic signals and roundabouts controls are commonly used in several at-grade junctions in urban areas for maximizing traffic efficiency and safety by separating traffic movements in time. The intersection performance is measured by comparing the parameters like- capacity, degree of saturation, delay, queue length, fuel consumption, operating costs and emission, etc. This research paper provides a comparative study of operational performance between a roundabout and signalized intersection at Gergi-Imperial. The traffic data on all approach of the intersection were collected by video camera during the most congested days of the week. The traffic volume obtained in different classes of a vehicle was converted to uniform vehicle fleet by the passenger car equivalency factor. The geometric data for the selected intersections were measured manually. Data analysis and processing were performed using SIDRA (Signalized and Unsignalized intersection Design and Research Aid) intersection software to compare the traffic flow condition at the intersection. The performance measures such as Average delay, Degree of saturation and Level of service at each intersection were interpreted for comparison. The capacities of the signalized intersection were found to be higher than the capacities of roundabout. Signalized intersection was found to be better than the roundabout in terms of the degree of operational performance. Keywords: Average delay, Intersection Capacity, SIDRA Software, Level of Service (LOS), roundabout, Signalized Intersection, Degree of Saturation