현장적용을 위한 연동형 반감응 신호제어 개발 및 분석

This paper compares per-mile risks posed by motor traffic to pedestrians and cyclists on urban major and minor roads. Carrying out new analysis of police injury data from 2005 to 2015, this study finds that per billion vehicle miles, motor vehicles on minor roads create more pedestrian casualties than motor vehicles on major roads. Specifically, for killed or seriously injured (KSI) casualties the rate per billion motor vehicle miles is 17% higher on minor roads (47 against 40 KSIs per billion vehicle miles), while for slight injuries it is 66% higher (188 against 123 slight injuries per billion vehicle miles). Examining the costs of injuries sustained, these are 7·4% higher for pedestrians per motor vehicle mile travelled on urban minor roads, compared with major roads. For cyclists, injuries per mile driven are similar on major and minor roads. These results suggest that re-routing motor traffic to major roads in urban areas may reduce pedestrian casualties. Cyclist safety on major roads should be improved to avoid unintended negative consequences and ensure positive outcomes for cycling.

Since 2006, INDOT has been preparing an annual five‐percent report that identifies intersections and segments on Indiana state roads that require attention due to the excessive number and severity of crashes. Many of the identified intersections are two‐way, stop-controlled intersections located on high‐speed, multi‐lane, rural roads. Some contributing design and human factors have been identified while other factors still await investigation. Multivariate ordered probit models have been developed to help identify additional factors of the frequency and severity of crashes. These models can estimate how much different factors increase the frequency of crashes at several levels of injury severity (fatal/incapacitating, non‐incapacitating/ possible, property‐damage‐only). They have a unique ability to account for unobserved but common conditions that affect all of the crash severity levels. Recommendations for safety countermeasures are made based on both of these research results and our study of published reports of other authors. The statistical analysis was performed on 553 existing intersections in Indiana and 72 existing intersections in Michigan using crash data reported during a four‐year period. The identified safety factors include: presence of horizontal curves within the intersection vicinity, traffic volume on the major road, land use, population of the area surrounding the intersection, and the minor road functional class (traffic volume on minor road unknown), nearby at‐grade railroad crossings, intersection conspicuity to drivers on the major road, acceleration lanes for both left and right turns, median width, intersection angle, and number of intersection legs. These results are in line with other research results as documented in the literature review. Based on the results of this and other studies, recommendations are made to improve safety at new intersections as well as at existing intersections. For new intersections, construction of medians wider than 80 feet is suggested. Where this is not possible and a narrower median needs to be constructed, adding a parallel acceleration lane for vehicles turning left from the minor road is suggested. Intersections should be placed at a sufficient distance from horizontal curves and from at‐grade railroad crossings. Solutions with indirect left-turn lanes (Michigan U‐turns, J‐turns) are recommended. At existing intersections experiencing excessive numbers of crashes involving vehicles from the minor road, median closure should be considered or a median opening should be restricted to certain maneuvers. Median acceleration lanes can be added in order to allow a two‐stage maneuver for left turns from the minor road. Enhanced guide and warning signage can be used to improve intersection conspicuity; adding road illumination can especially help at night. The practice of adding left‐ and right‐turn bays should be continued as this is a proven intersection safety improvement practice. Applying these countermeasures may help improve safety and avoid the construction of expensive grade separations. Finally, advanced intersection collision avoidance systems, such as road‐side dynamic signs warning drivers on the minor road about a short gap on the major road, should be the subject of pilot studies in Indiana. Experiments in other states have indicated that these systems help drivers choose safe gaps.

Automatic road identification and labeling in Landsat 4 TM images

A steady growth in traffic volumes in industrialized countries with dense human populations is expected, especially on minor roads. As a consequence, the fragmentation of wildlife populations will increase dramatically. In human-dominated landscapes, typically minor roads occur in high densities, and animals encounter them frequently. Traffic calming is a new approach to mitigate negative impacts by reducing traffic volumes and speeds on minor roads at a regional scale. This leads to a distinction between roads with low volumes as being part of the traffic-calmed area, whereas roads with bundled traffic are located around this area. Within the traffic-calmed area, volumes and speeds can be decreased substantially; this is predicted to decrease the disturbance and mortality risk for animals. Thus far, data on the effects of traffic calming on wildlife population persistence remain scarce. Using metapopulation theory, we derived a model to estimate thresholds in the size of traffic-calmed areas and traffic volumes that may allow persistent populations. Our model suggests that traffic calming largely increases the persistence of roe deer in a landscape with a dense road network. Our modeling results show trade-offs between traffic volume on roads within the traffic-calmed area and both the area of habitat available for this species in the traffic-calmed area and the size of the traffic-calmed area. These results suggest ways to mitigate the fragmentation of wildlife habitat by road networks and their expected traffic volumes

We used 38,709 fixes collected from December 2003 through June 2006 from 44 elk ( Cervus elaphus ) fitted with Global Positioning System collars and hourly traffic data recorded along 27 km of highway in central Arizona, USA, to determine how traffic volume affected elk distribution and highway crossings. The probability of elk occurring near the highway decreased with increasing traffic volume, indicating that elk used habitat near the highway primarily when traffic volumes were low (<100 vehicles/hr). We used multiple logistic regression followed by model selection using Akaike's Information Criterion to identify factors influencing probability of elk crossings. We found that increasing traffic rates reduced the overall probability of highway crossing, but this effect depended on both season and the proximity of riparian meadow habitat. Elk crossed highways at higher traffic volumes when accessing high quality foraging areas. Our results indicate that 1) managers assessing habitat quality for elk in areas with high traffic‐volume highways should consider that habitat near highways may be utilized at low traffic volumes, 2) in areas where highways potentially act as barriers to elk movement, increasing traffic volume decreases the probability of highway crossings, but the magnitude of this effect depends on both season and proximity of important resources, and 3) because some highway crossings still occurred at the high traffic volumes we recorded, increasing traffic alone will not prevent elk‐vehicle collisions. Managers concerned with elk‐vehicle collisions could increase the effectiveness of wildlife crossing structures by placing them near important resources, such as riparian meadow habitat.

PURPOSES : The intents of the study are to identify the accident factors and to demonstrate the potentials of tobit model as a tool to study the number of accidents on arterial roads segments. METHODS : This paper uses a tobit regression as a methodology to analyze the factors affecting the number of accidents. In pursuing the above goal, this study gives particular attentions to analyzing the data of 2,446 accidents (1,610 in major arterial roads and 836 in minor arterial roads) occurred on arterial roads in 2007 to 2010. RESULTS : First, 3 accident models which were classified by total arterial roads, major arterial roads and minor arterial roads, and were all statistically significant were developed. Second, the exclusive right-turn lane as common variable, and the number of accident, traffic volume, number of lanes, link length, rate of median, number of entrances, number of pedestrian crossings, number of curves, number of bus stops and exclusive left-turn as specific variables of the models were selected. Finally, the paired sample t-test could not be rejected the null hypotheses of three types of models. CONCLUSIONS : Using data from vehicle accidents on arterial roads, the estimation results show that many factors related to roadway geometrics and traffic characteristics significantly affect to the number of accidents.

As traffic volumes increase in many jurisdictions in both urban and rural areas, the demand on the highway network also increases. Specifically, as rural traffic volumes rise in Texas, the pressure on the state's network of two-lane highways rises accordingly. High proportions of heavy vehicles compound the problem and contribute to a decrease in safety as impatient drivers attempt to pass slower vehicles in no-passing zones or to pass trucks, despite diminished sight distance beyond such vehicles. Previous research in Texas demonstrated that periodic passing lanes can improve operations on two-lane highways with low to moderate volumes; these Super 2 highways can provide many benefits of a four-lane alignment at lower cost. The current Texas Roadway Design Manual contains these guidelines for highways with average daily traffic (ADT) lower than 5,000 vehicles per day. A current project expands on that research to develop design guidelines for passing lanes on two-lane highways with higher volumes. The project investigates the effects of volume, terrain, and heavy vehicles on traffic flow. This paper discusses findings from field observations of existing Super 2 highway corridors in Texas and computer modeling of traffic conditions on a simulated Super 2 corridor. Results indicate that passing lanes do provide added benefit at higher traffic volumes by reducing delay and percent time spent following. The incremental benefit of adding passing lanes or adding length to lanes diminished, and the effects of ADT on operations were more substantial than the effects of terrain or truck percentage for the study corridor.

Under mixed-mode traffic conditions prevailing on Indian roads at unsignalized intersections, it is commonly observed that vehicles entering from minor streets indulge in forceful gap creation/delay for the vehicles moving on the major road. Although this driving behavior has been reported in some of the published studies for Indian traffic conditions, a clear definition of such forceful entries is not available. An attempt has been made in this study to define this forceful entry phenomenon on the basis of changes in the speed of major streets’ vehicles approaching the intersection on a typical case of mixed-traffic environs. In this regard, field observations were recorded through videography to obtain the speed reduction threshold value for categorizing an entry as a forceful entry. To quantify the above, data in relation to various vehicle types approaching intersections and their associated speeds at the reference area were extracted at the approach arms of the intersection. On the basis of observations, collected data were divided into three scenarios: ( 1 ) vehicles on major roads reduce their speed when vehicles are absent on minor roads; ( 2 ) vehicles on major roads reduce their speed when vehicles are waiting on minor roads; and ( 3 ) vehicles on major roads reduce their speed when vehicles from minor roads have accepted the gap/lag for movement. The changes in speed in all the three scenarios were compared to identify forceful entries with the base case of normal traffic flow on the major road without the existence of forceful entry phenomenon. The study revealed that the speed reduction to the extent of 73% is considered as a forceful entry at the selected location. Furthermore, the study estimated the effect of forceful behavior on critical gap at unsignalized intersections.

This paper is concerned with the average delay to vehicles on the minor road at a junction where the traffic on the major road has absolute priority. It is assumed that vehicles on the major road arrive at random, and pass through at intervals of not less than a time f1. Vehicles on the minor road arrive at random and pass through at intervals of not less than f2. Further, they cannot enter the junction within a time ax after the previous vehicle on the major road. Thus one minor-road vehicle can pass through a gap of duration between aX and a + /32 in the major-road traffic, two can pass in a gap of between a + fl2 and a + 2/2, and so on. A formula is derived for the average delay to vehicles on the minor road when the system is in statistical equilibrium. Extensive tabulations of this formula have been made, and an extract from these is given. The practical implications of the results are not discussed in the paper, but it is hoped to compare the delays with those obtained with traffic-light control. The problem is similar to those of queueing with priority customers, of the 'service repeat' variety, but there is one important difference: at road junctions of the type considered there is a considerable loss of service time when changing from one type of ' customer' to the other. Typical values of /,J and /12' the two service times, are of the order of 1 or 2 sec., but a gap a of about 7 sec. between two priority 'customers' is required for any non-priority 'customers' to be served. An analysis of a similar problem has been given by Winsten (Beckmann, McGuire & Winsten, 1955), but this was based on more restrictive assumptions. Some special cases of the result obtained here were given by Tanner (1953).

We tested the hypothesis that road safety improves at junctions between minor roads and major roads if the minor roads are modally filtered to remove through traffic. We did this by using police-reported casualty data (2012–2024) to examine the effects of 113 Low Traffic Neighbourhoods (LTNs) implemented in London between 2015 and 2024. Our findings supported our hypothesis: LTN implementation was associated with a 14% reduction in total numbers of casualties at junctions between newly filtered minor roads and surrounding major roads (95% CI: -21% to -8%). This effect was generally consistent across casualty injury severity, casualty travel mode, and the presence of traffic-light controlled signals.

Investigating the impacts of crash prediction models on quantifying safety effectiveness of Adaptive Signal Control Systems

Accurately estimating annual average daily traffic (AADT) on minor roads is essential for assessing traffic-related air pollution (TRAP) exposure, particularly in areas where most people live. Our study assessed the direct and indirect external validity of three methods used to estimate AADT on minor roads in Melbourne, Australia.We estimated the minor road AADT using a fixed-value approach (assuming 600 vehicles/day) and linear and negative binomial (NB) models. The models were generated using road type, road importance index, AADT and distance of the nearest major road, population density, workplace density, and weighted road density. External measurements of traffic counts, as well as black carbon (BC) and ultrafine particles (UFP), were conducted at 201 sites for direct and indirect validation, respectively. Statistical tests included Akaike information criterion (AIC) to compare models' performance, the concordance correlation coefficient (CCC) for direct validation, and Spearman's correlation coefficient for indirect validation. Results show that 88.5% of the roads in Melbourne are minor, yet only 18.9% have AADT. The performance assessment of minor road models indicated comparable performance for both models (AIC of 1,023,686 vs. 1,058,502). In the direct validation with external traffic measurements, there was no difference between the three methods for overall minor roads. However, for minor roads within residential areas, CCC (95% confidence interval [CI]) values were −0.001 (−0.17; 0.18), 0.47 (0.32; 0.60), and 0.29 (0.18; 0.39) for the fixed-value approach, the linear model, and the NB model, respectively. In the indirect validation, we found differences only on UFP where the Spearman's correlation (95% CI) for both models and fixed-value approach were 0.50 (0.37; 0.62) and 0.34 (0.19; 0.48), respectively. In conclusion, our linear model outperformed the fixed-value approach when compared against traffic and TRAP measurements. The methodology followed in this study is relevant to locations with incomplete minor road AADT data.

Many traffic accidents are caused by unforeseen and unexpected events in a site that was hidden from the driver's eyes. Road design parameters determining required visibility are based on relationships formulated decades ago. It is worth reviewing them from time to time in the light of technological developments. In this paper, sight distances for stopping and crossing situations are studied in relation to the assumed visual abilities of autonomous vehicles. Current sight distance requirements at unsignalized intersections are based among others on speeds on the major road and on ac-cepted gaps by human drivers entering or crossing from the minor road. Since these requirements vary from country to country, regulations and sight terms of a few selected countries are compared in this study. From the comparison it is remarkable that although the two concepts, i.e. gap acceptance on the minor road and stopping on the major road have different backgrounds, but their outcome in terms of required sight distances are similar. Both distances are depending on speed on the major road: gap sight distances show a linear, while stopping sight distances a parabolic function. In general, European SSD values are quite similar to each other. However, the US and Australian guidelines based on gap acceptance criteria recommend higher sight distances. Human capabilities and limitations are considered in sight field requirements. Autonomous vehicles survey their environment with sensors which are different from the human vision in terms of identifying objects, estimating distances or speeds of other vehicles. This paper compares current sight field requirements based on conventional vehicles and those required for autonomous vehicles. Visibility requirements were defined by three vision indicators: distance, angle of view and resolution abilities of autonomous cars and human drivers. These indicators were calculated separately for autonomous vehicles and human drivers for various speeds on the main road and for intersections with 90° and 60° angles. It was shown that the required sight distances are 10 to 40 meters shorter for autonomous vehicles than for conventional ones.

This paper investigates the living environment in a residential area at Taman Melati in Kuala Lumpur, Malaysia. Traffic volume, NO2 emissions, noise level and streetlight illuminance were variables selected to measure the living environment. A questionnaire was also used to evaluate residents′ perceptions regarding their living environment. A high average traffic volume of about 7,800 vehicles per hour, especially along the arterial road (major road) was reported. Generally, a noise level in the range of 50-70 dB was measured in the residential area, and the average LAeq near the arterial road was about 76 dB. NO2 concentration in the residential area varied widely, between 0.01 ppm and 0.04 ppm; the average NO2 concentration was 0.018 ppm. The horizontal streetlight illuminance was measured under all streetlights and at every 5 m interval. The illuminance near the streetlights was high, but was low between them. Traffic noise proved to be a major limitation concerning a healthy living environment according to the residents of the study area. Even so, more than half the residents in the study area expressed satisfaction with the present living environment.

Influences of traffic volumes and wind speeds on ambient ultrafine particle levels—Observations at a highway electronic toll collection (ETC) lane