• Journal of Korean Society of Transportation
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• v.24 no.4 s.90
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• pp.93-101
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• 2006

The signalized intersections near highway-railroad grade crossing are operated without signal preemption in Korea when trains are approaching the crossing. This signal operation is very dangerous because queues from the intersection can extend back over the track, thereby creating the Potential for a serious vehicle-train accident. And the queues from the crossing can extend to the intersection with the normal signal operation while trains Pass the crossing. In this case the intersection is disrupted, and delay and the Potential for vehicle accident increase highly In order to improve the intersection performance and Protect the accident the crossings and intersections. signal Preemption designed to provide a special control mode should be implemented. In this study it was shown that intersection Performance near highway-railroad grade crossing improved using signal preemption. When signal Preemption is implemented at the test site, the delay was reduced by about 9sec/veh. Even though there were vehicle-train accidents at the crossing in all 30 simulations without signal preemption. there was no vehicle-train accidents at all when signal preemption is used.

• Journal of Korean Society of Transportation
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• v.26 no.5
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• pp.63-72
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• 2008

Signalized intersections are operated without a signal preemption control strategy in Korea, thus there is no priority treatment for an emergency vehicle passing through the intersections. In this paper, a signal preemption control strategy is introduced to improve the safety and operational efficiency of an emergency vehicle. Using the micro simulation tool, the effects on delay and travel speed of the signal preemption control strategy are analyzed for various traffic conditions to identify the general performance trends. Then, another simulation analysis is performed to verify the feasibility of the control strategy using real network data collected from field study. Results show that the preemption control strategy provides the positive impact on emergency vehicles' operation, but the positive impact is reduced as the v/c ratios increase. As expected, the average delays of the normal vehicles are slightly increased, but the magnitude is not significant. Therefore, it is expected that the introduction of the preemption control strategy in Korea would produce the positive social benefits.

• Journal of Korean Society of Transportation
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• v.25 no.2 s.95
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• pp.17-26
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• 2007

Because the prime objective of the current preemption methods at signalized intersections near highway-railroad grade crossings(IHRGCs) is to clear the crossing, secondary objectives such as safe pedestrian crossing time and minimized delay often are given less consideration or are ignored completely during the preemption. Under certain circumstances state-of-the-practice traffic signal preemption strategies may cause serious pedestrian safety and efficiency problems at IHRGCs. An improved transition preemption strategy(ITPS) that is specifically designed to improve intersection performance while maintaining or improving the current level of safety was developed by Cho and Rilett. Even if the new transition preemption strategy improved both the safety and efficiency of IHRGCs, the performance of the strategy is affected by train speed. Understanding the impact of this factor is essential in order to implement ITPS. In this paper, the effects of train speed were analyzed using a VISSIM simulation model which was calibrated to field conditions. It was concluded that the delay is affected more by train speed than the transitional preemption strategy and the safety of the intersection is not affected by train speed once an advanced preemption warning time(APWT) is equal to or greater than 90 seconds.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.5
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• pp.27-37
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• 2012

Even thought the firefighters have to hurry to the scene to extinguish the blaze, the fire engines could not rushed out due to the worst of traffic condition. Traffic signal control is one of the most important methods to minimize the fire engines's travel time. The focus of this paper is to develop a traffic control strategy, which is emergency vehicle preemption algorithm considering pedestrian in order to reduce travel time of emergency vehicle. This algorithm also includes recovering strategy after preemption signal to minimize the other vehicle's delay. In order to estimate the effectiveness of traffic control, traffic simulation was performed using VISSIM micro simulation tool for two different kinds of networks, which were non-coordinated corridor and coordinated corridor. The differences of travel time and average delay between emergency vehicle and ordinary vehicle were respectively estimated under pre-existed pretimed signal and preemption traffic control at two respective networks. The results of the simulation for the emergency vehicle, travel time was reduced to 36.8~43.3% under "Add or Subtract" method whereas it was reduced to 30.7~46.0% under "Dwell" method. In addition, in non-coordinated corridor case of ordinary vehicle, average control delay of "Dwell" method was increased 33.5% whereas it grew 0.5% under coordinated corridor. And "Add or Subtract" method was confirmed that average control delay of ordinary vehicle was increased 0.7% under non-coordinated corridor whereas it swelled 4.5% under coordinated corridor.

• Journal of Korean Society of Transportation
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• v.27 no.2
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• pp.179-187
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• 2009

Currently, the signalized intersections in Korea are operated without providing an emergency vehicle preemption control strategy. Thus, it might threaten the safety of the pedestrians and drivers on highways when an emergency vehicle faces congested traffic conditions. The existing preemption control is activated when an emergency vehicle is detected along a path. This enables emergency vehicles to progress uninterrupted, but it also increases the delay of other vehicles. In this paper, a revised preemption control strategy considering queue length restrictions is proposed to make both a progressive movement of an emergency vehicle and reduce delay of other vehicles simultaneously. By applying the preemption control strategy through a simulation study, it was shown that delay of an emergency vehicle decreased to 44.3%-96.1% and speed increased to 8.8%-42.0% in all 9 cases as compared with a conventional signal control. The existing preemption control is superior for oversaturated conditions (v/c >1.0) or a link length less than 200m. However, the preemption control considering queue length constraints shows better performance than the existing preemption control when the v/c is less than 0.8 and a link length is longer than 500m.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.3
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• pp.95-109
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• 2017

The golden time of emergency vehicle is directly connected to the public safety. Therefore, national attention has increased to cut down the emergency vehicle's travel time. In order to shorten the intial dispatch time of it, emergency preemption system was installed at five intersections, and after test operation, whether it could be introduced in the country was estimated. We analyzed the effect of the traffic volume, emergency vehicle's travel time, and queue length under preemption and non-preemption. In the verification of the emergency preemption system, it was confirmed that the emergency vehicle's travel time was reduced from 350% to 24% compared to non-preemption system(TOD). In the saturated condition, queue length were remained 15 minutes and near saturated condition was about 30 or 45 minutes. At the non-saturated condition, the queue length's difference between emergency preemption system and general signal was small.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.2
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• pp.39-47
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• 2012

In this paper, we have developed the system of emergency vehicle preemption signal control based on UTIS(Urban Traffic Information System) which have been deployed and operated in the national capital area. It considered the turning direction(through or left turn) of emergency vehicle at the signalized intersection in order to provide the consecutive progression of emergency vehicle and minimize the control delay of passenger cars. we adopted several EVP control modes such as phase insertion and phase adjustment mode. Also, we evaluated the possibility of field implementation via simulation analysis using CORSIM RTE(Run Time Extension) based HILS(Hardware In the Loop Simulation). We expect that the result of this research contribute to providing the right-of-way to emergency vehicle in this country.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.4
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• pp.345-353
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• 2010

A general solution in global self-position location of robot is to generate multiple hypothesis in self-position of robot, which is to look for the most positive self-position by evaluating each hypothesis based on features of observed landmark. Markov Localization(ML) or Monte Carlo Localization(MCL) to be the existing typical method is to evaluate all pairs of landmark features and generated hypotheses, it can be said to be an optimal method in sufficiently calculating resources. But calculating quantities was proportional to the number of pairs to evaluate in general, so calculating quantities was piled up in wide environments in the presence of multiple pairs if using these methods. First of all, the positive and promising pairs is located and evaluated to solve this problem in this paper, and the newly locating method to make effective use of calculating time is proposed. As the basic method, it is used both RANSAC(RANdom SAmple Consensus) algorithm and preemption scheme to be efficiency method of RANSAC algorithm. The calculating quantity on each observation of robot can be suppressed below a certain values in the proposed method, and the high location performance can be determined by an experimental on verification.

• Journal of Korea Multimedia Society
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• v.11 no.8
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• pp.1051-1058
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• 2008

The advancement of technology for image processing and communications makes it possible for current traffic signal controllers and vehicle detection technology to make both emergency vehicle preemption and transit priority strategies as a part of integrated system. Present]y traffic signal control in crosswalk is controlled by fixed signals. The signal control keeps regular signals traffic even with no traffic, when there is traffic, should wait until the signal is given. Waiting time causes the risk of traffic accidents and traffic congestion in accordance with signal violation. To help reduce the risk of accidents and congestion, this paper explains traffic signal control system for the adaptive priority order so that signal may be preferentially given in accordance with the situation of site through the object detect images.

• Journal of the Society of Disaster Information
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• v.16 no.4
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• pp.650-657
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• 2020

Purpose: In this study, the effectiveness of pilot project of PLSP (Priority Lane and Signal Preference) system, which was operated in Cheongju City, was analyzed. Method: The priority signal was operated by a police officer switching to a blue signal when approaching a fire truck through CCTV, and the priority lane of emergency vehicles was displayed on the road to enable preferential traffic. VISSIM simulation analysis was performed for the 1.2km section (3.8km) of the pilot project section and vehicle data was analyzed for some of the test operation sections. Result: Simulation analysis shows that the moving speed of the emergency vehicle can be increased by 42 km/h with the introduction of PLSP, which can be increased by approximately twice the speed. Travel time was reduced by about 3 minutes, and considerable improvements of 69% compared to cities that are not operating was analyzed. The pilot operation of Cheongju City showed a time-shortening effect of about two minutes on average, with the average time reaching 4 minutes and 14 seconds in the first period and the average time reaching 5 minutes and 40 seconds in the second period. Conclusion: The system has been shown to be effective in minimizing time-to-site arrival of emergency vehicles.