• Title, Summary, Keyword: Limit Speed

Search Result 921, Processing Time 0.042 seconds

Development of the Speed Limit Model for Harbour and Waterway(II) - The Method of Speed Limit Decision and Application -

  • Kim, Deug-Bong;An, Kwang
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.21 no.3
    • /
    • pp.274-282
    • /
    • 2015
  • This research is the result on calculating the logical speed limit through certain process which some elements must be considered on selecting the speed limit of harbour and waterway. The suggested speed limit select model on this research is processed from 1~6 steps by forming a professional group of experts. Each step has its information which 1st step(water division), 2nd step(selecting the model vessel and vessel applied with speed limit.), 3rd step(selecting the maximum and minimum speed range on each section), 4th step(evaluation on the safeness of traffic), 5th step(suggesting the appropriate speed limit), 6th step(execution and evaluation.). The appropriate speed limit was decided on consideration of the safety of maritime traffic on the range of the maximum speed and the minimum speed. This model was used to derive the appropriate speed limit on the harbour water and Busan harbour entrance waterway. As the result, the harbour water was calculated to be 6.9 knots, the appropriate speed limit of Busan entrance harbour was 9.3 knots. The present calculation of the speed limit on the approaching channel area is 10 knots, inner harbour area is 7 knots, which are similar to the result of the speed limit. This research is the first research on selecting the speed limit model and has its limits on finding the perfect speed limit result. More detailed standards on the safeness of traffic evaluation must be found and additional study is necessary on discriminating consideration of the elements. This research has its value which it provides instances of aboard cases on guidelines of selecting the speed limit.

The Generation Method of ATO Speed Profile in the Moving Block System (이동폐색 시스템에서 자동운전 속도 프로파일 산출 방법)

  • Choi, Dong-Hyuk;Cho, Chan-Ho;Quan, Zhonghua;Choi, Sun-Ah;Ryou, Myung-Seon
    • Proceedings of the KSR Conference
    • /
    • /
    • pp.1092-1099
    • /
    • 2011
  • This paper is concerned with the ATO speed profile generation method in the moving block system. The ATO speed profile is calculated using the acceleration limit and the jerk limit to improve ride comfort. In addition, the speed limit and stop distance provided from ATP profile should be considered to ensure safety. In the moving block system, the speed limit and the stop position are frequently changed in real-time. Therefore, the ATO speed profile should be regenerated immediately according to change of the speed limit and the stop position, within the acceleration limit and the jerk limit. In this paper, the ATO speed profile generation method is proposed, which considers not only frequent changes of the speed limit and the stop position but also acceleration limit and jerk limit. Futhermore the simulation result is presented to verify usefulness of this method.

  • PDF

A study on Korea road conditions assessment for Speed Limit Information Function(SLIF) (제한속도정보제공장치(SLIF)에 대한 한국 환경 평가 분석)

  • Lee, Hwasoo;Sim, Jihwan;Yim, Jonghyun;Lee, Hongguk;Chang, Kyungjin;Yoo, Songmin
    • Journal of Auto-vehicle Safety Association
    • /
    • v.7 no.4
    • /
    • pp.26-30
    • /
    • 2015
  • Exceeding the speed limit during vehicle driving is a key factor in the severity of lots of road accidents, and SLIF(Speed Limit Information Function) application is in the initial phase in Korea. SLIF helps the drivers to observe a speed limit when they are driving by providing alert and informing the current limit speed information based on external data using camera and/or digital map, for that reason, environmental conditions could be causes of SLIF malfunctions. In this study, design adequacy analysis of SLIF in respect of false recognition as the Korea traffic environment has been performed. As tentative results, road conditions and structure of speed limit sign as well as system performance often caused misrecognition.

Field Survey on Suitable In-service Wind Speed Limit for Tower Crane Operation (타워크레인의 작업 중지 풍속에 대한 현장 실태 조사 연구)

  • Lee, Eui Ju;Shin, Sung Woo
    • Journal of the Korean Society of Safety
    • /
    • v.33 no.1
    • /
    • pp.103-108
    • /
    • 2018
  • Since tower cranes are susceptible to wind loads, the operation of the tower crane should be ceased when it exposed to a strong wind. For this reason, even in Korea, the operation limit for wind loading on the tower crane is regulated by a law. Recently the Korean law in which provided the wind speed limit to cease the tower crane operation has been revised from "instantaneous wind speed of 20 m/s" to "instantaneous wind speed of 15 m/s". Although this revision is expected to reduce safety risks in tower crane operation, some field operators still insist to lower the wind speed limit. However, in many countries "wind speed of 20 m/s" is normally used as the maximum in-service wind speed for tower cranes. Therefore, the investigation of the proper wind speed for regulation would be helpful to secure the safety of the tower crane operation under windy condition. In this study the validity of the revised wind speed limit is investigated with the surveys targeted to both tower crane practitioners and parties of concerned in construction companies, in which various questions was provided for a suitable wind speed limit and the answers were analyzed. The results showed that the revised wind speed limit is acceptable to tower crane practitioners as well as the parties of concerned in construction companies and is satisfying the structural stability requirement for in-service state tower crane. Therefore, it can be concluded that the revised wind speed limit is valid in humanly safety point of view.

Characteristics of Geometric Conditions Affecting Freeway Travel Speed : Focused on Speed Limit Change (고속도로 주행속도 변화에 영향을 미치는 도로기하구조 특성분석 : 제한속도 상향전후 비교를 중심으로)

  • Hong, Sungmin;Oh, Cheol
    • International Journal of Highway Engineering
    • /
    • v.16 no.5
    • /
    • pp.83-90
    • /
    • 2014
  • PURPOSES : The purpose of this study is to identify the factors affecting the effectiveness of speed limit change that is defined as the amount of increased travel speed. METHODS : A ordered logit model was adopted to analyze the relationship between the change in travel speed and contributing factors. A stretch of Kyungbu freeway was selected for the analysis because the Korea expressway corporation has raised speed limit from 100km/h to 110km/h since September 1st in 2010. RESULTS : The results showed that geometric design elements, speeding cameras, and section length were identified as factors contributing the effectiveness. Contributing geometric design elements include the number of horizontal curves and vertical curves that do not meet the design requirement with 110km/h speed limit. CONCLUSIONS : The outcome of this study will be used for establishing various traffic operations and control strategies for freeway speed management.

Characterization of Potential Impact of Carbon Emissions under Speed Limit Enforcement on the Uninterrupted Flow (연속류 위험도로구간에서의 운전자의 도로속도규정 준수에 따른 온실가스 변화량 연구)

  • Lee, Jong Hak;Lee, Soong Bong
    • International Journal of Highway Engineering
    • /
    • v.19 no.6
    • /
    • pp.175-182
    • /
    • 2017
  • PURPOSES : Road sectors contribute approximately 16 % of total GHG emission rates in South Korea. Engineers and experts expend significant efforts to identify countermeasures for the reduction of carbon emission. This study aims to determine how total carbon emission rates change depending on whether or not there is speed limit enforcement. METHODS : In this study, Lamm's travel speed profile theory is first adopted to select the hazard road, which sections are designated as speed limit enforcement. Second, Motor Vehicle Emission Simulator (MOVES) was used to simulate the carbon emission on the road. RESULTS : The total carbon emission rate under speed limit enforcement was 10,773 g higher than the condition without speed limit enforcement in the designated road. This might affect acceleration, which can lead to increased emissions. CONCLUSIONS : There would be no researches about proving the relationship how speed limit enforcement has an effect on carbon emission. The result of our study can provide valuable guidelines regarding road safety and eco-friendly roads.

Changes in air pollutant emissions from road vehicles due to autonomous driving technology: A conceptual modeling approach

  • Hwang, Ha;Song, Chang-Keun
    • Environmental Engineering Research
    • /
    • v.25 no.3
    • /
    • pp.366-373
    • /
    • 2020
  • The autonomous vehicles (AVs) could make a positive or negative impact on reducing mobile emissions. This study investigated the changes of mobile emissions that could be caused by large-scale adoption of AVs. The factors of road capacity increase and speed limit increase impacts were simulated using a conceptual modeling approach that combines a hypothetical speed-emission function and a traffic demand model using a virtual transportation network. The simulation results show that road capacity increase impact is significant in decreasing mobile emissions until the market share of AVs is less than 80%. If the road capacity increases by 100%, the mobile emissions will decrease by about 30%. On the other hand, driving speed limit increase impact is significant in increasing mobile emissions, and the environmentally desirable speed limit was found at around 95 km/h. If the speed limit increases to 140 km/h, the mobile emissions will increase by about 25%. This is because some vehicles begin to bypass the congested routes at high speeds as speed limit increases. Based on the simulation results, it is clear that the vehicle platooning technology implemented at reasonable speed limit is one of the AV technologies that are encouraging from the environmental point of view.

A study on Korean drivers' acceptance and traffic sign conditions assessment for Speed Assistance Systems (속도제한 지원장치에 대한 운전자 인식도 및 도로환경 분석)

  • Lee, Hwa Soo;Cho, Jae Ho;Yim, Jong Hyun;Lee, Hong Guk;Chang, Kyung Jin;Yoo, Song Min
    • Journal of Auto-vehicle Safety Association
    • /
    • v.7 no.3
    • /
    • pp.30-34
    • /
    • 2015
  • This study examined the Korean drivers' acceptance of SAS(Speed Assistance systems) and traffic sign conditions in Korea roads for SLIF(Speed Limit Information Function) that is a part of SAS. Exceeding the speed limit is a factor in the severity of many road accidents and SAS would help the driver to observe a speed limit by warning and/or effectively limiting the speed of the vehicle. SAS are in the initial phase in Korea, Korean drivers could not be familiar with automatical speed limiting during driving, SAS interface design would be considered to be more readily acceptable to the public. And advanced SAS have been introduced onto the market which are able to inform the driver of the current speed limit based on camera and/or digital maps based SLIF. These systems are based on external data using sensors, so environmental conditions are an important factor which could cause malfunction of SLIF functions.

Development of Speed Limit Safety Wheel used by Trochoid Gear (트로코이드 기어를 이용한 속도제한 안전바퀴 개발)

  • Lee, Dongkeun;Lee, Siyoung;Hong, Youngjun;Koo, Jae-Mean;Seok, Chang-Sung
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.29 no.12
    • /
    • pp.1340-1345
    • /
    • 2012
  • Industrial products developed in recent years have focused on usability and stability. Especially, for the products used in daily life, steady efforts have been made to secure the safety. Among them, the products equipped with wheels such as strollers, shopping carts, and carriers can occur the safety accidents by unintended over speed at a ramp. Therefore, development of speed limit device is required to prevent such accidents. However, the existing speed limit devices are very expensive and have a complex drive principle, so it's generally difficult to apply them. In this study, a simple speed limit wheel is suggested which can replace the previous complex and inconvenient speed limit devices. The developed speed limit wheel can be simply applied to existing products by changing the wheels. In addition, it has an advantage to operate only by mechanical mechanism without power supply. Thus it can minimize the cost and waste of resources. For this purpose, the operating condition of the target products was analyzed, and trochoid gear mechanisms were selected for the speed limit. Based on this, finite element analysis was conducted to estimate the operating mechanism. After the prototype of the wheel was produced, the performance under various conditions was tested and has been improved.

Real-time Speed Limit Traffic Sign Detection System for Robust Automotive Environments

  • Hoang, Anh-Tuan;Koide, Tetsushi;Yamamoto, Masaharu
    • IEIE Transactions on Smart Processing and Computing
    • /
    • v.4 no.4
    • /
    • pp.237-250
    • /
    • 2015
  • This paper describes a hardware-oriented algorithm and its conceptual implementation in a real-time speed limit traffic sign detection system on an automotive-oriented field-programmable gate array (FPGA). It solves the training and color dependence problems found in other research, which saw reduced recognition accuracy under unlearned conditions when color has changed. The algorithm is applicable to various platforms, such as color or grayscale cameras, high-resolution (4K) or low-resolution (VGA) cameras, and high-end or low-end FPGAs. It is also robust under various conditions, such as daytime, night time, and on rainy nights, and is adaptable to various countries' speed limit traffic sign systems. The speed limit traffic sign candidates on each grayscale video frame are detected through two simple computational stages using global luminosity and local pixel direction. Pipeline implementation using results-sharing on overlap, application of a RAM-based shift register, and optimization of scan window sizes results in a small but high-performance implementation. The proposed system matches the processing speed requirement for a 60 fps system. The speed limit traffic sign recognition system achieves better than 98% accuracy in detection and recognition, even under difficult conditions such as rainy nights, and is implementable on the low-end, low-cost Xilinx Zynq automotive Z7020 FPGA.