Reduced Speed Zone Research Articles

Commercial Adaptive Cruise control (ACC) and capacity drop at freeway bottlenecks

Vehicle automation has already become commercially available. Today’s mainstream vehicles are equipped with Adaptive Cruise Control (ACC) to automate longitudinal car-following. However, ACC’s limited detection range and delayed reaction hinder the vehicle’s ability to respond promptly to speed changes, and ACC could amplify minor disturbance into severe stop-and-go waves and form queues at bottlenecks. Consequently, the discharge flow could be lower than the maximum flow observed in absence of queues or congested conditions, also known as capacity drop. Microscopic simulation of freeway bottlenecks consisting of a single lane with reduced speed zone, multilane with an on-ramp merge, and multilane with an off-ramp diverge demonstrates that ACC vehicles lead to capacity drop at freeway bottlenecks. For the single lane reduced speed zone, the extent of capacity drop for ACC could be either less or more severe than that of human driven vehicles. However, the multilane freeway on-ramp and off-ramp bottlenecks are more susceptible to capacity drop than human driven vehicles, due to ACC significantly amplifying disturbances caused by lane changes, merging, and diverging.

Effects of Reduced Speed on the Benefits and Pollution of Yangtze River Ships

Yangtze River shipping causes air pollution in cities along the route, and the cost to ships should be considered while controlling emissions. This paper analyzes the impact of speed and other factors on ship emissions and profit. It discusses the potential scenarios of reducing operating costs and the management implications of influencing factors while meeting environmental policies. Partial basins are established as reduced speed zones (RSZs) based on predicting air pollutant concentrations, then modeling the operation and pollutant emissions of container ships. The research indicates that reducing speed appropriately inside RSZs can effectively reduce pollutant emissions in the area, with the extent of variation in the emissions and profit being slight for the entire voyage. Reducing speed throughout the voyage also achieves emission reduction but, ultimately, increases the ship’s sailing time. Meanwhile, the extension of RSZs, the fuel efficiency, and so forth, also affect the emissions and profit of the ship. These findings can provide insights for operators in reducing costs, as well as for environmental regulators in adjusting emission reduction regulations dynamically.

Social Innovation in Active Mobility Public Services in the Megacity of Sao Paulo

This article aims to explore the relationship between social innovation and opportunities for innovation in public services, focusing on a range of initiatives intended to improve services and infrastructure for pedestrians in the city of São Paulo, the largest Brazilian megacity, namely: Reduced Speed Zone, Safe Routes to School, and Complete Street. We apply the multiagent framework for innovation in services, incorporating nine variables that characterize social innovation. As for the main results, in the local context, there is the role of third-sector organizations in creating and introducing solutions for active mobility services through co-creation. Co-creation was identified as a key process and is highlighted in actions to obtain community involvement, interviews to measure the acceptance of the project and detect potential points of improvement not foreseen in the pilot project, participatory workshops, installation of informative and interactive panels, preparation and approval of the temporary intervention project, and joint discussion and analysis with municipal agencies about the points that could receive the temporary intervention. The initiatives are recent and cover specific geographic–temporal boundaries. There is a need to deepen the dialogue between social innovation and service innovation with the co-design and co-construction approaches proposed in this paper, applied in different political, economic, urban, and social contexts. In addition, some barriers are highlighted relating to the lack of public funding, compliance with national regulations, political will, non-partisan actions, and long-term vision. There are potentials for the continuous introduction of innovations for the improvement of public services for pedestrians, promoting participatory restructuring as a form of (re)appropriation of urban public spaces.

Estimation of Shipping Emissions in Developing Country: A Case Study of Mohammad Bin Qasim Port, Pakistan.

Transportation has the highest dependence on fossil fuels of any sector and accounts for 37% of carbon dioxide (CO2) emissions. Maritime transportation is responsible for around 940 million tons of CO2 and approximately 3% of global emissions annually. The significant increase in shipping activities around the globe has magnified the generation of toxic pollutants. In recent years, shipping emissions have received significant attention in developed countries due to global climate change, while in developing countries, researchers are making enormous efforts to tackle this catastrophic and pressing issue. This study considers Muhammad Bin Qasim Port (MBQP), Karachi, Pakistan as a case study. This study employed an activity-based or bottom-up approach with a standard procedure to estimate the various anthropogenic pollutants emissions including particular matters (PM10 and PM2.5), nitrogen oxide (NOx), sulfur dioxide (SO2), carbon monoxide (CO), CO2, methane (CH4), non-methane volatile organic compound (NMVOC), and hydrocarbon (HC) under different operational modes, i.e., hoteling, maneuvering, and reduced speed zones. The results indicated that CO2 was the highest contributor with a proportion of 92%, NOx 5%, and SO2 1.5% for all three operational modes. Moreover, the results indicated that container ships account for 64% of overall emissions, followed by tankers for 24%. Regarding the monthly trend, the findings revealed that November and December had the highest emission rates, with over 20% of the total emissions recorded. This study’s findings will assist stakeholders and policymakers to prioritize maritime emissions in developing countries.

Driver Response to a Dynamic Speed Feedback Sign at Speed Transition Zones Along High-Speed Rural Highways

Research was conducted to assess the effectiveness of a dynamic speed feedback sign (DSFS) as a speed reduction strategy at speed transition zones along five high-speed rural highways in northern Michigan. The DSFS was positioned on the shoulder in advance of the reduced speed limit at each community and was programmed to display speeds of approaching vehicles alternating with the upcoming reduced speed limit. Using handheld LIDAR guns, vehicle speeds were tracked through each speed transition area before and after installation of the DSFS. The DSFS was found to have a significant speed reduction effect throughout each of the five speed transition zones. The speed reductions generally began when the DSFS came into the motorists’ view, and the speed reduction effect increased as motorists approached DSFS. The greatest speed reduction effects were observed at the DSFS location itself, where speeds were 3.2 to 7.8 mph lower with the DSFS present, and these reductions were sustained on entry to the community. Similarly, drivers were 78.8 to 92.4% less likely to exceed the reduced speed limit with the DSFS present. Positioning the DSFS further upstream typically resulted in earlier speed reductions, although this effect became negligible once vehicles reached the reduced speed zone entering the community. Based on the study findings, continued use of DSFS for speed management at speed transition zones entering communities on high-speed rural roadways is recommended. When used in this context, the DSFS should be positioned 250 to 650 ft upstream of the reduced speed limit.

Urban Commons in Active Mobility Experiences

Our study focuses on the challenges facing sustainable urban mobility in the megacity of Sao Paulo. We aim to explore the panorama of active mobility initiatives, proposing to analyze the relationship between urban commons and innovation in public services. We selected the Reduced Speed Zone and Complete Street initiatives, which aim to improve road safety conditions (public services focused on common infrastructure), active mobility and access to public transport, and may also potentially help to reduce noise levels, improve air quality (social dilemmas/common issues/negative externalities) and reduce greenhouse gas emissions (global commons). Based on an analytical model for interpreting innovation in services, considering competences and techniques originating from the provider (municipal government) and users (through civil society organizations), our findings identified innovations at a local level within infrastructure treatment for pedestrians. These public services were introduced in a participatory process and a collective re-appropriation of urban space. The projects contribute to the development of service provider competences, related to various interactions with civil society, resulting in a systemic view with regard to the uses, local dynamics and behavioral aspects of the users themselves. Service provider techniques may be both temporary and permanent intervention methodologies, besides methodologies for project impact evaluations. These techniques are associated with tactical urbanism as a technique for temporary urban interventions. User techniques were identified for application of the propensity score-matching method, which aims to evaluate the impacts of an instance of intervention through the comparison of groups, as well as through technical inspections and local interviews. The relationship management generated relational and organizational competences for civil society organizations. However, despite the advances indicated by the analyzed experiences of active mobility – highlighting the role of civil society organizations – and by some progress made in the regulatory framework, innovative practices have been restricted to the treatment of infrastructure for pedestrians, a change of speed limit for vehicles, and horizontal signaling to mark the perimeter of these areas. Therefore, there is a large-scale potential for the continued introduction of innovations regarding the improvement and scale gains of public services for pedestrian mobility, promoting participatory restructuring as a form of (re)appropriation of urban public spaces by its own users, improving the current negative externalities and social costs of urban mobility.

Environmental effects of emission control areas and reduced speed zones on container ship operation

To examine the dual environmental effects of emission control areas (ECAs) and reduced speed zones (RSZs), this study formulates an integrated container ship operation optimization model based on the fundamental facet of liner-service market. Capturing the critical characteristics of container ship operation, the proposed model explicitly incorporates the entire voyage that consists of container ship sailing and port activities as well as nonproductive stay in port. Compared to the separate establishment of ECAs, joint regulations of ECAs and RSZs can lead to more SOx emission reduction within it and less profit loss of the container ship by means of differentiated operation. Meanwhile, the optimal operation speed inside ECAs and RSZs of profit maximization is 10.638 knots, applied to the case study of CSCL Pacific Ocean, the container ship sailing MEX route from Far East (Shanghai, China) to Persian Gulf (Dammam, Saudi Arabia). These findings can provide insights for liner operators in carrying out differentiated operation from the demand side, as well as environmental regulators in adjusting emission reduction regulations dynamically.

Emission Inventory of Marine Traffic for the Port of Šibenik

The paper estimates the exhaust emissions of marine traffic in the port of Šibenik. The results of the analysis were obtained by including the following gaseous pollutants: nitrogen oxide (NOX), sulphur oxide (SOX), particulate matter (PM), volatile organic compounds (VOCs) and carbon dioxide (CO2) as greenhouse gas. In order to gain results and estimate the emission of harmful gases in the port of Šibenik, the passenger and the cargo throughput were taken into account. The activities of the ship during which the exhaust gases are emitted into the atmosphere are slow cruising in the reduced speed zone, manoeuvring and hotelling. The “bottom-up” method used in the emission estimation takes into account the ship’s engine power, engine load factor, fuel type, the emission factor, time of cruising and time hotelling in the port of Šibenik. The results of the analysis have shown that approximately 70 % of total emissions come from passenger ships (cruise ships) and 30 % from cargo ships.

Driving speed choice: The role of conscious monitoring and control (reinvestment) when driving

This study aimed to examine the role of reinvestment - the propensity to consciously monitor and control actions (movement specific reinvestment) and to consciously monitor and evaluate decision making processes (Decision specific reinvestment) while driving in everyday risky scenarios. The study also aimed to evaluate the association between reinvestment and previously validated driver attitude measures. Fifty one participants completed a series of questionnaires (Driving Self-Efficacy Scale, Driver Attitude Questionnaire, Movement Specific Reinvestment Scale, Decision Specific Reinvestment Scale) after which they completed a test phase in a driving simulator. In the test phase, driving scenarios included roads with different markings (i.e., double yellow, wide centrelines, wire rope barriers, Audio Tactile Profiled markings) and alerting scenarios (i.e., police car present, high crash risk area sign, reduced speed zone). Results revealed that on risky roads (wide centrelines), participants with a high propensity for decision specific reinvestment drove slower than those with a low propensity. Driver experience, attitudes towards speeding and scores on the Decision Reinvestment subscale of the Decision Specific Reinvestment Scale significantly predicted speed choice. More experienced participants with higher scores on the Decision Reinvestment subscale were more likely to drive slower and participants with worse attitudes towards speeding were likely to drive faster. Participants with a low propensity for movement specific reinvestment (specifically, Movement Self-Consciousness) reduced their speed to a greater extent than those with a high propensity when driving in the police car scenario. There was some evidence to suggest that high decision specific and movement specific reinvesters were more likely to be involved in crashes and receive driving infringements. The current study is the first to demonstrate a significant relationship between reinvestment and driving. The implications of these findings for road safety are discussed.

Estimating socio-economic impact from ship emissions at the Port of Incheon

Ports create harmful effects on their adjacent population because ships discharge noxious gases like SOX, NOX, and particulate matter (PM). To tackle this problem, some ports started to control emission through regulations such as Emission Control Areas (ECA) and Reduced Speed Zone (RSZ). This paper estimates the social cost of ship emission and eco-efficiency at the Port of Incheon (POI). We further examine how the ECA and RSZ designation can reduce the social cost. The estimation is based on the activity-based approach, where ship type, engine, and movement are used to measure fuel consumption and then emission. Results suggest that the social cost of ship emission at the POI amounts to $90,805,478. The eco-efficiency of the POI, compared to the one at the Port of Las Palmas in another study, is substantially better. Under RSZ, the corresponding emission abatement values are $4,485,308, $2,642,009 and $21,932,435 from SO2, NOX and PM reduction, respectively. If 1.0% and 0.1% sulfur fuel are used complying with rules of the ECA, the social cost savings amount to $8,174,947 and $12,868,842 from SO2 reduction.

Evaluation of Effects of Ship Emissions Control Areas

With the growing number of ships, emissions from the shipping industry now rank as one of the three major sources of air pollutants. This has aroused the concern of more and more countries and international organizations. To control shipping emissions, three ship emissions control areas (ECAs) have been set up in China. This study first evaluates the effectiveness of the ECA designed to reduce sulfur dioxide (SO2) emissions in the Shanghai, China, port area, and then estimates carbon dioxide (CO2) emissions reduction by regarding the ECA as a reduced speed zone by using container ships’ data. The case study of the port of Shanghai finds that for the year 2020, a reduction in SO2 emissions by at least 103,998.17 tons can be achieved with the 12-nmi ECA of Shanghai port, CO2 emissions can be reduced by 827,733.64 tons with a 12-knot speed limit in the 12-nmi ECA, and an additional SO2 reduction of 522.23 tons can be achieved by slow steaming within the ECA. The results also show that adoption of a shoreside power supply system can lead to a remarkable reduction of all the air pollutant emissions inventories. The positive effect of emissions reduction is much more significant than the extra costs incurred by ship operators and ports. The goal of reductions in emissions to improve the air quality of port areas could be achieved through adopting these “green” port policies in the future.

Forgetting induced speeding: Can prospective memory failure account for drivers exceeding the speed limit?

It is generally assumed that drivers speed intentionally because of factors such as frustration with the speed limit or general impatience. The current study examined whether speeding following an interruption could be better explained by unintentional prospective memory (PM) failure. In these situations, interrupting drivers may create a PM task, with speeding the result of drivers forgetting their newly encoded intention to travel at a lower speed after interruption. Across 3 simulated driving experiments, corrected or uncorrected speeding in recently reduced speed zones (from 70 km/h to 40 km/h) increased on average from 8% when uninterrupted to 33% when interrupted. Conversely, the probability that participants traveled under their new speed limit in recently increased speed zones (from 40 km/h to 70 km/h) increased from 1% when uninterrupted to 23% when interrupted. Consistent with a PM explanation, this indicates that interruptions lead to a general failure to follow changed speed limits, not just to increased speeding. Further testing a PM explanation, Experiments 2 and 3 manipulated variables expected to influence the probability of PM failures and subsequent speeding after interruptions. Experiment 2 showed that performing a cognitively demanding task during the interruption, when compared with unfilled interruptions, increased the probability of initially speeding from 1% to 11%, but that participants were able to correct (reduce) their speed. In Experiment 3, providing participants with 10s longer to encode the new speed limit before interruption decreased the probability of uncorrected speeding after an unfilled interruption from 30% to 20%. Theoretical implications and implications for road design interventions are discussed. (PsycINFO Database Record

The impact of vessel speed reduction on port accidents

Reduced-speed zones (RSZs) have been designated across the world to control emissions from ships and prevent mammal strikes. While some studies have examined the effectiveness of speed reduction on emissions and mammal preservation, few have analyzed the effects of reduced ship speed on vessel safety. Those few studies have not yet measured the relationship between vessel speed and accidents by using real accident data. To fill this gap in the literature, this study estimates the impact of vessel speed reduction on vessel damages, casualties and frequency of vessel accidents. Accidents in RSZ ports were compared to non-RSZ ports by using U.S. Coast Guard data to capture the speed reduction effects. The results show that speed reduction influenced accident frequency as a result of two factors, the fuel price and the RSZ designation. Every $10 increase in the fuel price led to a 10.3% decrease in the number of accidents, and the RSZ designation reduced vessel accidents by 47.9%. However, the results do not clarify the exact impact of speed reduction on accident casualty.

Surge Phenomena Analytically Predicted in a Multi-stage Axial Flow Compressor System in the Reduced-Speed Zone

Surge Phenomena Analytically Predicted in a Multi-stage Axial Flow Compressor System in the Reduced-Speed Zone

Methodological Approach for Evaluation of Roundabout Performances through Microsimulation

In the literature, there are many methodologies that allow the evaluation of roundabout performances (Capacity, Levels Of Service, etc.): analytical models (HCM, HBS etc.), statistical models (TRRL, SETRA) etc. Each technique considers some aspects of the roundabout in comparison to others (geometric elements, vehicular flow and behavioral parameters). Obtained results are often not comparable among themselves because of distinctive peculiarities of each method. Today, the best way to solve this problem is by using a refined simulation software of vehicular circulation. However, along with a more and more refined analysis of microsimulation software algorithms, it is frequently necessary for each user (researcher, engineer, planner, etc.) to know the real sensitivity of these packages with regard to the most important key parameters. In this paper the Authors introduce the results of a wide survey conducted on an ample range of virtual roundabout scenarios by the use of a modern simulation software. Each scenario describes a fixed roundabout phenomenon using the following variables: geometric elements (inscribed circle radius, circulatory roadway, central and splitter islands etc.); characteristics of the traffic flow (dynamic traffic assignment, approach speed, circulatory speed and reduced speed zones, etc.); behavioral features (priority rules, minimum gap, minimum headway, etc.). The results are presented from the evaluation of stop-line delays.

Evaluating the effects of green port policy: Case study of Kaohsiung harbor in Taiwan

The paper evaluates the effectiveness of strategies designed to reduce these pollutants in port areas, based on a newly developed assessment model to calculate emissions. The case study found that the strategy of reducing the ship’s speed to 12 knots is most effective in cutting fuel consumption and costs, as well as emissions. Adopting an onshore power supply system could reduce CO2 emission by 57.16% and PM by 39.4%. By adopting the strategies of both reduced speed and cold ironing emissions control, a reduction in emissions of 71% to 91% can be achieved with a 20 nautical mile reduced speed zone. Therefore, the goals of reductions in emissions to improve port areas air quality could be achieved through adopting a green port policy in the future.

A simulation model of freeway lane closures

A model to simulate traffic operations at freeway lane closures is described. The model logic is based on a rational description of the behavior of the drivers in a freeway lane closure situa tion, and the program is written in SIMSCRIPT 11.5. An applica tion of the model is illustrated with evaluation of potential safety impacts of reduced speed zones in freeway lane closures at differ ent levels of assumed driver compliance.