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Studies carried out have revealed that every day around three thousand people lose their lives in the world due to traffic accidents and poor air quality. Large cities, with their millions of inhabitants and vehicles, face many problems relating to vehicular traffic. In 2015, the speed limit was modified on several roads in the city of São Paulo, Brazil. However, in 2017, the speed limits were increased again, but not on all previous routes. This study analyzed the impact of this change on the number of accidents and pollutant concentrations, over a period of ten years, comparing the periods before and after the implementation of the measure, using real data collected and provided by the authorities of the city and the state transit and environmental companies, on more than forty routes and two nearby air-quality stations. The results showed a clear reduction in the number of accidents without victims on the roads of the city of São Paulo, starting in 2010. Although the restrictive measures imposed by government officials may have contributed to the decrease in the number of accidents, the number of fatalities has not changed so much. Air pollution has not improved substantially with speed changes, as new speed increases have been linked to new episodes of congestion. The average number of fatalities due to accidents has been increasing since 2010 and accidents are becoming more serious. The application of a general linear statistical model (GLM) estimated the impact of the speed reduction policy in terms of the number of injuries avoided per month: 43.4 and 14.1 on other roads and on the Pinheiros highways, respectively. The results highlight the need for a constant data collection by the authorities in cities with high vehicle traffic. The important temporal time trend in terms of reduction of injuries, but not in terms of fatalities and air quality, shows the need to apply joint public policies, not only speed reduction, but also the use of new technologies and raising drivers' awareness of the problem. [ABSTRACT FROM AUTHOR]

Background: In 2016, large-scale 20 miles per hour speed limits were introduced in the United Kingdom cities of Edinburgh and Belfast. This paper investigates the role that scientific evidence played in the policy decisions to implement lower speed limits in the two cities. Methods: Using a qualitative case study design, we undertook content analysis of a range of documents to explore and describe the evolution of the two schemes and the ways in which evidence informed decision-making. In total, we identified 16 documents for Edinburgh, published between 2006 and 2016, and 19 documents for Belfast, published between 2002 and 2016. Findings: In both cities, evidence on speed, collisions and casualties was important for initiating discussions on large-scale 20 mph policies. However, the narrative shifted over time to the idea that 20 mph would contribute to a wider range of aspirations, none of which were firmly grounded in evidence, but may have helped to neutralize opposing discourses. Discussion and conclusions: The relationship between evidence and decision-making in Edinburgh and Belfast was neither simple nor linear. Widening of the narrative appears to have helped to frame the idea in such a way that it had broad acceptability, without which there would have been no implementation, and probably a lot more push back from vested interests and communities than there was. [ABSTRACT FROM AUTHOR]

Abstract Background In 2016, large-scale 20 miles per hour speed limits were introduced in the United Kingdom cities of Edinburgh and Belfast. This paper investigates the role that scientific evidence played in the policy decisions to implement lower speed limits in the two cities. Methods Using a qualitative case study design, we undertook content analysis of a range of documents to explore and describe the evolution of the two schemes and the ways in which evidence informed decision-making. In total, we identified 16 documents for Edinburgh, published between 2006 and 2016, and 19 documents for Belfast, published between 2002 and 2016. Findings In both cities, evidence on speed, collisions and casualties was important for initiating discussions on large-scale 20 mph policies. However, the narrative shifted over time to the idea that 20 mph would contribute to a wider range of aspirations, none of which were firmly grounded in evidence, but may have helped to neutralize opposing discourses. Discussion and conclusions The relationship between evidence and decision-making in Edinburgh and Belfast was neither simple nor linear. Widening of the narrative appears to have helped to frame the idea in such a way that it had broad acceptability, without which there would have been no implementation, and probably a lot more push back from vested interests and communities than there was.

Stakeholders in many municipalities worldwide are committed to promoting cycling and improving cycling provision. Scarcity of space is a major issue in most of these cities, particularly for main streets with significant movement and place functions. Multiple demands exist on these streets, including moving pedestrians, cyclists, motorised vehicles, parking, people waiting at public transport stops, or staying in the street for place activities. Mixing cyclists and motorised vehicles in the same space in the carriageway might be the only possible solution for cycling provision in these contexts, which is applied in many German cities.The aim of this study is to evaluate the acceptance of cycling in mixed traffic, which we measure as the proportion of cyclists riding on the carriageway versus on the pavement. The empirical work in this study is based on video observations at 273 study sites with a total length of 124 km located in 13 cities in Germany. 260 of these study sites have no marking for cyclists, and 13 have bicycle pictograms. A total of 34 874 cyclists are recorded at these study sites. A logistic regression model is used to quantify the effect of exposure and infrastructure characteristics on the proportion of cyclists on the carriageway. Volumes of motorised vehicles, lane widths > 3.00 m and city type show a significant negative effect on the acceptance of cycling on the carriageway. Cyclist volumes, bicycle pictograms, and a speed limit < 50 km/h significantly increase the likelihood of cycling on the carriageway. The model is then applied to develop evidence-based recommendations on appropriate conditions for mixed traffic provision for cyclists, ensuring pre-defined levels of acceptability. Cycling in mixed traffic without bicycle pictograms should only be recommended with traffic volumes of a maximum of 400 vehicles per hour and a speed limit of

ABSTRACTThe focus of this study is to identify potential road links suitable for implementing a variable speed limit (VSL) sign by analyzing real-world traffic speed data collected over one year in Charlotte, North Carolina, United States. Exploratory and bivariate analyses were conducted to examine variations in traffic speed patterns during weekdays and weekends across eight specific timespans. The results revealed that road links with lower posted speed limits consistently experienced traffic speeds exceeding the posted speed limits. The mean traffic speeds are generally close to the posted speed limits for road links with higher posted speed limits while the 85th percentile speeds exceeded the posted speed limits, indicating a potential need for VSL sign implementation. The road links with 40 mph or 50 mph posted speed limits have a unique pattern compared to road links of other posted speed limit clusters. The mean traffic speed on these road links decreased as the standard deviation increased. The findings contribute to an improved understanding of traffic speed patterns and provide valuable insights for implementing a VSL sign.

To enhance the safety and integration of vulnerable road users (pedestrians and cyclists) into the transportation system, a growing number of European cities, including Vilnius, are aligning their traffic management solutions with the concept of street humanisation. The Naujamiestis district is the first city district in Vilnius to undergo these changes. To assess the impact of street humanisation strategies on road safety, this preliminary paper analyses data from the road accident history database for the period 2018-2021 and results from instantaneous vehicle speed analysis. The results of the road accident database history are presented graphically and using heat maps. The data from the instantaneous speed analysis are analysed using the Kruskal-Wallis and Mann-Whitney-Wilcoxon non-parametric statistical criteria. The findings indicate that the concept of street humanisation is effective in enforcing 30 km/h speed limit. The analysis of road accident data history shows a decrease in the number of accidents and their consequences in the study area and the entire city of Vilnius between 2018 and 2022. However, it is currently challenging to determine whether street humanisation concept directly contributes to the decline in road accidents. Therefore, it is proposed to revisit the analysis in the future. [ABSTRACT FROM AUTHOR]

To enhance the safety and integration of vulnerable road users (pedestrians and cyclists) into the transportation system, a growing number of European cities, including Vilnius, are aligning their traffic management solutions with the concept of street humanisation. The Naujamiestis district is the first city district in Vilnius to undergo these changes. To assess the impact of street humanisation strategies on road safety, this preliminary paper analyses data from the road accident history database for the period 2018–2021 and results from instantaneous vehicle speed analysis. The results of the road accident database history are presented graphically and using heat maps. The data from the instantaneous speed analysis are analysed using the Kruskal- Wallis and Mann-Whitney-Wilcoxon non-parametric statistical criteria. The findings indicate that the concept of street humanisation is effective in enforcing 30 km/h speed limit. The analysis of road accident data history shows a decrease in the number of accidents and their consequences in the study area and the entire city of Vilnius between 2018 and 2022. However, it is currently challenging to determine whether street humanisation concept directly contributes to the decline in road accidents. Therefore, it is proposed to revisit the analysis in the future.

• The 80 km/h speed limit is associated with a significant reduction in fatalities. • Estimated benefits are between 300 and 350 lives saved. • Estimated effects vary between counties, illustrating the potential impact depending on the local context. • The dynamics of the measure evolve over time. Introduction : Speeding is considered to be a major contributor to road fatalities and injuries worldwide. Inappropriate speeding behavior is associated with a high casualty burden. It could be responsible for at least 30% of road accidents. Method : In 2018, the French authorities decided to introduce a new speed limit. They lowered the speed limit to 80 km/h on the unseparated interurban network. The aim was to reduce the number of fatalities and injuries and to implement some measures in line with international commitments. This paper uses different econometric models applied to time series for different groups of counties. Results : The results show a significant positive contribution of the new speed limit. The estimated number of lives saved is between 300 and 350. The overall reduction in the number of fatalities is 10%. The results also show a differentiated impact according to the local context and the different dynamics at play. Conclusions and Practical Applications : The results of this paper are in line with the scientific literature on speed limit reductions. They represent a validation of a debated public decision, while at the same time consolidating the body of knowledge on the subject, helping the decision-maker to adopt an appropriate measure to improve road safety performance. [ABSTRACT FROM AUTHOR]

The study aimed to evaluate safe and eco-driving performances of vehicle car-following behaviors in a vehicle platoon under foggy conditions. Eight drivers participated in a multi-user driving simulation experiment, and their driving performances in a vehicle platoon were collected. A Fault Tree model was established to evaluate the collision risk of the vehicle platoon, and the VT-Micro model was adopted to calculate vehicles' fuel consumption, CO2 emission, and NOx emission. The results showed that heavy fog exponentially increased the collision risk of a vehicle platoon, which cannot be compensated by adaptive behavior, and it also increased fuel consumption and NOx emission during the car-following process. At the speed limit of 60 km/h, the safe and eco-driving performances of the vehicle platoon under foggy conditions have been effectively improved. This study also found that the vehicles at the rearward positions in a vehicle platoon tended to keep short car-following gaps and large speed adjustments, which was the main cause of higher collision risks. The study provides a better understanding of the safe and eco-driving features of the vehicle platoon under foggy conditions. The established fault tree provided theoretical references for the real-time monitoring of collision risk in a vehicle platoon. [ABSTRACT FROM AUTHOR]

Correct signage belongs to critical factors affecting road traffic safety. During a naturalistic driving study in Poland major mistakes associated with signage were noticed and analysed: road works were announced and speed limits were reduced from 120 km/h to 70−80 km/h, but no road construction could be found. Measurements of drivers’ speed showed their complete disregard of the limitations: average speed of light vehicles remained at 113 km/h and lorries at 88 km/h. Assessment of the encountered 683 road signs revealed 12.5% of them to be inadequate (10.9% falsely informed drivers). Evaluation of contrast ratio of road markings (their replacement was the claimed reason for road work) showed low values both before and after re-placement (Weber contrast 0.6). It is hypothesised that erroneous road signage and its contradiction with the visible road features are contributing to the permanent disobedience of traffic rules in Poland and are decreasing road safety.

Current analytical free-flow speed models consider all rural two-lane highways as the same road type despite their different functional significance in the network. The aim of this paper is to develop a prediction model for free-flow speed as a function of speed limit and road geometric characteristics for different classes of rural two-lane highways. The research was conducted on 50 representative sections of the two rural classes of two-lane highways equipped with automatic traffic counters in Serbia. In order to develop the appropriate models, it was necessary to determine the threshold values of vehicle time headway in the free-flow for both classes of rural two-lane highways, based on the total number of 191,720 vehicles. The obtained results show that there are differences in the threshold values of free-flow time headway for different road classes. Namely, it was determined that the values of free-flow time headway for Class I amounted to 6.3 s, and for Class II to 8.4 s. The free-flow speed prediction model for different road classes showed that speed limit had the highest impact on free-flow speed for Class I and II highways, followed by horizontal curve radius and shoulder width.

Speed limits should provide a balance between safety and traffic flow. However, setting a speed limit generally involves selecting a base speed (e.g., operational speed, design speed) and adjusting it with several other variables. For example, in Brazil, the standard guidelines list a series of factors that influence speed limits, but they do not provide a clear methodology to choose a speed limit for a highway segment. Therefore, under current Brazilian practice, the decision-maker is faced with a subject decision that mostly relies on expert judgment. This paper proposes a fuzzy expert system for setting Brazilian highway speed limits. Six input variables are considered in the system. Membership functions and fuzzy rules were extracted from experts’ evaluations of simulated highway scenarios. The experts evaluated the scenarios using linguistic variables and proposed speed limits. Then, a Mamdani fuzzy controller was developed. The outputs of the controller were compared to the expert’s answers for the simulated highway scenarios. The system was further validated considering two case studies of highway sections in Brazil. Results showed that the fuzzy system is able to provide outputs that agree with the experts’ evaluations and with the existing speed limits. The fuzzy controller developed in this study can be used to assist practitioners in setting highway speed limits on Brazilian highways.

• Speed and crash data were compared before and after the onset of the pandemic on low-volume rural freeways in Michigan. • Changes in general risk-taking behavior of the drivers was also compared for crash-involved drivers. • The pandemic was shown to increase travel speeds, as well as the severity of traffic crashes. • Speed and safety trends reverted back towards pre-pandemic levels at sites where speed limits were increased but remained elevated at sites where speed limits did not increase. • Crash involved drivers in 2020 were more likely to not wear seat belts, drive under the influence of drugs or alcohol, drive when they were sick or fatigued, or involve in hit-and-run crash. The COVID-19 pandemic disrupted various aspects of day-to-day life in unprecedented ways. This included significant reductions in travel that corresponded with travel restrictions imposed to contain the spread of the virus. This study evaluated changes in driver speed selection and crash/injury risk over the course of the pandemic on rural freeways in Michigan. Daily speed data and monthly crash data were analyzed from 2015 to 2020 to investigate changes that corresponded to the onset of the COVID-19 pandemic. The results showed that during the initial periods of lockdown, mean speeds increased by 2.2–2.4 mph across all sites, while the total crash frequency was lower by 28%–45% compared to pre-pandemic years. Crashes also tended to be significantly more severe during the early stages of the pandemic. Interestingly, these changes were less pronounced on sites with 70-mph speed limits as compared to sites where speed limits were increased to 75 mph in 2017. However, as travel restrictions were lifted, speeds regressed towards long-term averages on the 75-mph sites while the higher speeds were maintained at sites with 70-mph limits. The increase in injury severity appears to be attributable to higher speeds, as well as increases in other high-risk behaviors during the pandemic, such as non-use of seat belts and driving under the influence of drugs or alcohol. Some of these effects are also due to differences in terms of the population of drivers that were on the road during the pandemic. The results provide important insights as to the increases in severe crashes that coincided with the onset of the pandemic. [ABSTRACT FROM AUTHOR]

Two major characteristics that can impact the frequency and severity of traffic crashes are average speed and speed variance. This paper investigated these characteristics on 49 multilane highway segments in Jordan and developed prediction models for three different conditions: free (no enforcement), camera, and police enforcement. Speed data were collected during off-peak periods with fair weather conditions. Multiple linear regressions and nonlinear regressions were used to develop speed variance and average speed models. For the free condition, speed variance mainly depends on the difference between design speed and speed limit (DS-SL), with the speed variance decreasing as the difference reduces, while the average speed was positively correlated with the design speed. Camera enforcement causes speed variance and average speed to be positively correlated and linearly dependent with the speed limit. A quadratic relationship was found between speed variance during police enforcement and DS-SL, while the average speed during police enforcement depended on the speed limit and design speed. These modeling results, along with analysis of the collected data, can help operating agencies and roadway designers determine how various enforcement strategies affect average speed and speed variance and better set speed limits on existing and future roadways to improve safety. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 is a pandemic that affects road traffic flaw and crashes globally. This study attempted to compare the situation of road traffic crashes in the city of Budapest before and after the SARS-CoV-2 pandemic to better understand its long-term percussive effects. The study considers 12208 road traffic crashes that registered between 20 May 2018 - 31 December 2021. The rate and severity of road traffic crashes during the SARS-CoV-2 pandemic examined by using a percentage frequency distribution and a severity index. This study depicted that most crashes reported during the normal daytime between15:01-18:00 (peak hour). The study indicated that during the SARS-CoV-2 pandemic the road traffic crashes were reduced by 20.15%. A rear-end collision was one of the most common type of catastrophes highly registered. Road users, particularly drivers, heavily endorsed crashes. Even though the proportion of road traffic crashes caused by alcohol consumption was modest (6%), the rate of alcohol consumption and its concentration increased slightly during the SARS-CoV-2 pandemic. At the same time the number of crashes caused by high-speed traffic maneuvers reduced. Improper interpretation of road traffic signs, road pavement condition and failure to respect proper sight distance were influential reasons of road traffic crashes among the top. Meanwhile, the distributional impact of careless driving in the aftermath of the SARS-CoV-2 pandemic causes a shift in rank. Therefore, this study proved that during SARS-CoV-2 pandemics road traffic crashes reduced, the rate and concentration of alcohol consumption increased, and careless driving was encouraged. [ABSTRACT FROM AUTHOR]

Variable speed limits (VSL) aim at improving safety and traffic fluidity by increasing drivers’ awareness. In the present simulator study, VSL displayed on overhead gantries on a motorway were also displayed on a mobile phone, fixed on the vehicle’s centre console, with distance-based triggers (250 m vs. 500 m from the overhead gantry). Results showed drivers (N = 20) complied with the in-vehicle information, which was congruent with the upcoming gantry. The sooner the in-vehicle VSL, the faster the speed when speed limits increased. Similarly, the sooner the in-vehicle VSL, the slower the speed when speed limits decreased. Later in-vehicle VSL resulted in lower speed homogeneity, which is a safety concern. Speed homogeneity was greater when no in-vehicle VSL were displayed. Finally, the 70 mph VSL were affecting driving behaviour differently. These results suggested that there might be traffic disruption and more erratic longitudinal vehicle control on real roads.

Road traffic accidents are a significant global concern, particularly in developing countries such as India, where the number of accidents is increasing due to inadequate safety features on vehicles and poor visibility at night. In response, a study has been conducted to design and develop safety measures to reduce accident severity and minimize casualties. This research paper proposes several safety measures, including a new system that allows the driver to access the vehicle even without the keys and addresses common issues such as sharp turns and seatbelt engagement that can prevent serious injuries in accidents. The study provides a comprehensive overview of safety technologies designed to prevent accidents and reduce fatalities. [ABSTRACT FROM AUTHOR]

Variable speed limits (VSL) aim at improving safety and traffic fluidity by increasing drivers' awareness. In the present simulator study, VSL displayed on overhead gantries on a motorway were also displayed on a mobile phone, fixed on the vehicle's centre console, with distance-based triggers (250 m vs. 500 m from the overhead gantry). Results showed drivers (N = 20) complied with the in-vehicle information, which was congruent with the upcoming gantry. The sooner the in-vehicle VSL, the faster the speed when speed limits increased. Similarly, the sooner the in-vehicle VSL, the slower the speed when speed limits decreased. Later in-vehicle VSL resulted in lower speed homogeneity, which is a safety concern. Speed homogeneity was greater when no in-vehicle VSL were displayed. Finally, the 70 mph VSL were affecting driving behaviour differently. These results suggested that there might be traffic disruption and more erratic longitudinal vehicle control on real roads. [ABSTRACT FROM AUTHOR]

Martensitic transformations enable various emerging applications like the shape memory effect and elastocaloric applications in NiTi. Increasing the speed of this transformation can shorten the response time for actuation and increase the power density of caloric cooling systems. Up to now, research on the speed and possible time limits of the martensitic transformation in NiTi has been limited to milli- and microsecond experiments. The dynamics of the transformation for shorter time scales are therefore unknown. Here, we report the fastest transformations in NiTi so far by heating an epitaxial NiTi film with a ns laser pulse and tracking the martensitic transition with in - situ synchrotron x-ray diffraction. We find that the martensite to austenite transition upon heating can proceed within the 7 ns pulse duration of the laser, but it requires substantial overheating as the rate of the transformation increases with the driving energy. The austenite to martensite transition is slower because cooling proceeds by conductive heat transfer, but with appropriate undercooling, the complete transformation from martensite to austenite and back only takes 200 ns. We compare our results to previous experiments on the Heusler alloy Ni–Mn–Ga and (K, Na)NbO _3 and find very similar trends, which reveal that fast martensitic transformations in general follow a universal scaling law.

Purpose – In service, the periodic clashes of wheel flat against the rail result in large wheel/rail impact force and high-frequency vibration, leading to severe damage on the wheelset, rail and track structure. This study aims to analyze characteristics and dynamic impact law of wheel and rail caused by wheel flat of high-speed trains. Design/methodology/approach – A full-scale high-speed wheel/rail interface test rig was used for the test of the dynamic impact of wheel/rail caused by wheel flat of high-speed train. With wheel flats of different lengths, widths and depths manually set around the rolling circle of the wheel tread, and wheel/rail dynamic impact tests to the flats in the speed range of 0–400 km/h on the rig were conducted. Findings – As the speed goes up, the flat induced the maximum of the wheel/rail dynamic impact force increases rapidly before it reaches its limit at the speed of around 35 km/h. It then goes down gradually as the speed continues to grow. The impact of flat wheel on rail leads to 100–500 Hz middle-frequency vibration, and around 2,000 Hz and 6,000 Hz high-frequency vibration. In case of any wheel flat found during operation, the train speed shall be controlled according to the status of the flat and avoid the running speed of 20 km/h–80 km/h as much as possible. Originality/value – The research can provide a new method to obtain the dynamic impact of wheel/rail caused by wheel flat by a full-scale high-speed wheel/rail interface test rig. The relations among the flat size, the running speed and the dynamic impact are hopefully of reference to the building of speed limits for HSR wheel flat of different degrees.

Road accident due to overspeeding is a common occurrence in a developing nation such as Nigeria. Therefore, the need for a device capable of notifying a vehicle driver when the allowed speed limit of an area is exceeded arises. In this work, a microcontroller based automobile speed limiting device and alarm control system was designed and developed. The core components employed for the system design include Arduino Nano microcontroller, 1602 liquid crystal displays (LCD) module, light-emitting diodes (LEDs), buzzer, 18650 battery, I2C, infrared detectors and push buttons. Data gathering and circuit designs were implemented with microcontroller as focal point using suitable design models. Performance test was carried out on the developed system and the device’s reading error was determined. The developed automobile speed limiting device and alarm control system was functional and performed satisfactorily during testing. The reading error of the device was evaluated as 5.83%. The developed speed limiting device, apart from being suitable and efficient for vehicle speed measurement, could also be deployed for general applications requiring speed measurement. [ABSTRACT FROM AUTHOR]

This article investigates the effect of a decrease in the speed limit for motor vehicles on bicycle commuting in French cities. I use a difference-in-differences event study design to measure a possible causal effect of motor vehicle speed limits on changes in bicycle traffic. I do not find any effect of the reduction of the speed limit from 50 km/h to 30 km/h on bicycle commuting. This result is important for public policy design, since increasing the number of bicycles is one of the benefits that politicians expect from decreasing the speed limit for motor vehicles. [ABSTRACT FROM AUTHOR]

In the hot season, there is a positive relationship between the number of accidents per thousand registered vehicles and air temperature, due to the fact that high temperatures and solar activity can have a significant negative impact on the condition of drivers. As a rule, the creation of an emergency is preceded by a violation of traffic rules. Therefore, the identification of the type and number of violations committed by drivers at high ambient temperatures is relevant. The purpose of the work is to assess the impact of high ambient temperatures on the structure and frequency of traffic violations. Based on a literature review, the article states that at present there is no methodology for assessing the impact of high ambient temperatures on the characteristics of traffic violations. As an information platform, data from the Wialon — GPS/Glonass system are used, which allow you to objectively assess the characteristics of driving activity and the number of traffic violations. The work uses methods of mathematical statistics. The main result of the work, which constitutes the scientific novelty of the study, is the revealed increasing dependence of the total number of traffic violations on the average monthly ambient temperature. The structure of such violations is determined. The most significant, based on the impact on the accident rate, violations are: exceeding the speed limit and abrupt and dangerous maneuvers. It has been found that the total number of violations of the rules increases during periods with high ambient temperatures by 94% compared to months with moderate temperatures. The largest number of violations consists in exceeding the speed limit — 97.8% of their total number. The practical significance of the work consists in obtaining objective information about accidents at high ambient temperatures, on the basis of which it becomes possible to develop organizational and technological measures aimed at improving road safety. The areas of further research are related to the creation of an information platform for theoretical and methodological tools aimed at preventing high accidents of road transport in the hot season.

Ship generated waves (SGW) can cause bank erosion, disturbance to moored boats and bad impact on the environment especially in confined water. One of the important vessel parameters that will affect the SGW is the speed of the boat. The speed limit determination for fishing boats in confined water will be discussed which can be used as a reference to decide the maximum boat or ship speed. The confined water of Mersing River has been chosen for the current study. This river is a busy river located in Johor in the southeast area of Peninsular Malaysia. The limited speed is needed in this river because the river is restricted to many boat activities. The typical boat particulars in Mersing River are 14.05 m in length, 4.35 m in breadth and 1 m in draft. The field experiment has been conducted with several scenarios considering the speed and tidal conditions. The results of the experiment were used to determine the maximum energy of SGW in this area. By using trendline characteristics, the formula of maximum energy was generated by considering the speed of the boat. The Brisbane River Criteria in Australian River has been selected due to the same characteristic with Mersing River. Hence, the reference for allowable energy was defined in this study. By using this river criteria, the limit of the boat speed was provided for all tidal conditions (ebbing, slack and flooding), and it was found that the allowable speed as the speed limit in the Mersing River is 5 knots. This will reduce bank erosion, disturbance to moored boats, environmental impacts and energy consumption. Moreover, the generating process of the formula can be a reference to get the speed limit at particular area as the river in other areas.

Road traffic safety is a crucial global objective. It is important for every country to review and improve road safety policies and strategies, based on an objective understanding of its own road traffic safety situation in the world. With the aim of contributing to such a review and understanding, this study conducted a multi-country survey to gather information about various facts related to legislation, enforcement, and education, which are designed to achieve safer drivers in nine countries, by using a common format. This paper introduces the results of the survey with a particular focus on legislation and enforcement regarding speed limit violations and red-light-running as well as on education within the driving licensing systems. It highlights variations, in terms of penalty settings and enforcement levels, in different countries; it also examines the training durations necessary for acquiring a driving license and license renewal procedures. In this way, it demonstrates the potential and significance of understanding the relative position of each country in terms of road traffic safety through an international comparison despite its limited information.

In the field of vehicle control systems, the primary objective is to ensure the safety of road users. The intricate dynamics of road vehicles necessitate a high level of precision. Vehicle safety encompasses a multitude of considerations, including vehicle trajectory, prevailing traffic conditions, road structure, and meteorological factors. This study employs an Artificial Neural Network (ANN) trained with human driver data using SCANeR Studio software to evaluate the risk for the driver. The risk has been defined as a five-level parameter, which depends on the potential danger of a situation, where speed and direction play a crucial role. The system incorporates a simulator, an ANN, and a display interface to present the surroundings and communicate important information to the driver. This research employs a simulated driving scenario comprising a multi-lane roundabout with vehicles travelling in different directions to simulate real-world challenges. Risk estimation is achieved through a Time Delay Neural Network (TDNN) trained with various information about the environment in relation to the driven vehicle. The research employs a Jackknife technique for overall evaluation and introduces an adaptive algorithm for speed limit setting. The findings demonstrate the stability, generality, and practical applicability of the ANN in enhancing road safety. [ABSTRACT FROM AUTHOR]

Two comments submitted in critique of our paper (Gössling et al. 2023) present an opportunity to discuss principles of CBA and their use in transport contexts. The critique needs to be discussed in context, as CBA is not an objective tool of evaluation and relies on specific assumptions. For this reason, we begin our response with an introduction to the German transport context, including developments in car ownership and background on the German Climate Protection Act that legally requires all economic sectors to reduce emissions. This framing is important to correctly understand our response to Sieg (2024) as well as Eisenkopf et al. (2024). Overall, we note that many of their criticisms lack merit, while others depend on viewpoint. We conclude that, specifically considering current price levels for fuels, our findings are not in question: a speed limit is warranted for welfare reasons; it is supported by a majority of the population; and it can help closing the emission gap in the transport sector. Findings are also discussed within the wider framework of "desirable" transport systems, illustrating the limitations of CBA and the dangers of tailoring results in ways that lend credibility to specific forms of transport governance, as apparently favored by Sieg (2024) and Eisenkopf et al. (2024). [ABSTRACT FROM AUTHOR]

Gössling et al. (2023) perform a Cost-Benefit Analysis (CBA) of a 130 kph speed limit on German highways (Autobahnen). They find that the social benefits of the policy significantly outweigh its social costs, generating a welfare gain of almost €1 billion annually. In this commentary, we point to several serious shortcomings in their analysis, mainly caused by disregarding fundamental principles of economic CBA and adopting misleading ad hoc assumptions. We conclude that their CBA is neither suitable nor sufficient to evaluate the economic efficiency of a speed limit policy in Germany. [ABSTRACT FROM AUTHOR]

Gössling et al. (2023) claim to calculate the welfare effect of a 130 kph speed limit in Germany. By ignoring tax revenues from gasoline and diesel, they overestimate the welfare gain by about 378 million Euros. A speed limit raises travel times. Gössling et al. (2023) calculate travel time increases with a simplistic approach that underestimates the costs with a magnitude of their complete (tax adjusted) welfare effect. A speed limit induces some traffic to switch mode or not to travel at all. The reduced costs of less car travel are decisive for their calculation, but the losses of consumer rent associated with reduced travel are ignored. Gössling et al. (2023) do not calculate a value that is related to the welfare changes of a highway speed limit of 130 kph for Germany. [ABSTRACT FROM AUTHOR]

The increasing number of vehicles every year has led to the rising potential of vehicle accidents. In 2015, there were 556 fatalities from 6,231 accident cases occurred in Jakarta, through regulation of the Minister of Transportation Republic Indonesia No: 111 in 2015, it has been issued firm vehicle speed restrictions, but there is no positive impact because the speed limit of each vehicle cannot be done automatically by the highway location, so the need for innovation to design a tool that can meet these needs. The method in this research is developing a device that can break the flow of fuel quickly to hold the vehicle's speed with a Global Positioning System (GPS) as a trigger to drive the relay that has been installed on the engine. The results of this study are devices that have been installed in truck and bus engines capable of holding the speed. The result shows that the voltage has been calculated was at 10 km/h produce 1.2 volts, and the highest speed of 70km/h produce 10.7 Volt. GPS in speed limiter is also compared with the Map application. The result shows a slight difference either in latitude or longitude, where the smallest differences in latitude and longitude were about 0.00" and 0.05", respectively. In addition, the GPS speed limiter well performs to limit the speed of trucks and buses for 32 km/h in pedestrians, 58km/h on the highway and 52 km/h on a toll road.

Background: The city of Zurich progressively pursuits a strategy of reducing road traffic noise by lowering the speed limit to 30 km/h on street sections that exceed the legal noise limits.Aim of this study was to evaluate the effects of the reduced speed limit on noise levels (Lday and Lnight), noise annoyance, self-reported sleep disturbance, perceived road safety, and in particular, to elucidate if the reduced speed limit leads to a shift of exposure–response relationships towards lower effects. Methods: We surveyed about 1300 randomly sampled inhabitants, in a repeated measures study, before and after the speed rule changeover from 50 km/h to 30 km/h along 15 city street sections, by postal questionnaire. Concurrently, individual noise exposure calculations based on traffic counts and on-site speed measurements were carried out before and after the changeover. Results: Road traffic noise Leq's at the loudest façade point dropped by an average of 1.6 dB during day and 1.7 dB at night. A statistically significant decrease of noise annoyance and of self-reported sleep disturbances was observed, as well as a moderate but significant increase of perceived road safety. Most importantly, the exposure–response relationships for annoyance and sleep disturbance were shifted towards lower effects in the 30 km/h condition by, depending on receiver point, between about 2 dB and 4 dB during the day and about 4 dB at night, indicating lower effects at the same average level. This is a hint that, in addition to lower average exposure levels alone, other factors related to the lower driving speed additionally reduce noise annoyance and sleep disturbance. Conclusions: City dwellers probably benefit from traffic speed reductions to a greater degree than would be expected from the reduction in average level attained by the lower driving speed alone.

Abstract The maximum delivery pressure and the maximum rotational speed determine the power density of axial piston pumps. However, increasing the speed beyond the limit always accompanies cavitation, leading to the decrease of the volumetric efficiency. The pressure loss in the suction duct is considered a significant reason for the cavitation. Therefore, this paper proposes a methodology to optimize the shape of the suction duct aiming at reducing the intensity of cavitation and increasing the speed limit. At first, a computational fluid dynamics (CFD) model based on the full cavitation model (FCM) is developed to simulate the fluid field of the axial piston pump and a test rig is set to validate the model. Then the topology optimization is conducted for obtaining the minimum pressure loss in the suction duct. Comparing the original suction duct with the optimized one in the simulation model, the pressure loss in the suction duct gets considerable reduction, which eases the cavitation intensity a lot. The simulation results prove that the speed limit can increase under several different inlet pressures.

This paper evaluated the significance of the posted differential speed limits (DSL) on traffic safety and operation along interstate highways in South Carolina. This paper defines DSL as the difference between the posted maximum and minimum speed limits. The paper used vehicle speed and traffic crashes for analysis. The evaluation results showed over 99% of all vehicles complied with the posted 45 mph minimum speed limit and more than 50% of drivers drove above the posted maximum speed limit regardless of the posted maximum speed limits. The results also indicated that speed variations increased as the DSL increased. However, the safety evaluation showed conflicting results on the impacts of the DSL on safety. The results showed the DSL had negative implications on crashes per AADT per lane. This is attributed to increased interactions between slower and faster-moving vehicles in the traffic stream. On the contrary, it was observed that segments with higher DSL had fewer crashes per mile per lane than the segments with the lower DSL. These results suggest there is a need to conduct more research to quantify the efficacy of posting the minimum speed limit because there were no problems observed with motorists driving too slowly on interstate highways. The results provide important information on the efficacy of posting minimum speed limits to improve the uniformity of traffic flow and safety.

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