Pedestrian Accidents in Kentucky: 1972-1973

Pedestrian accident data in Kentucky were analyzed for 1972 and 1973 on a rural, urban, and statewide basis. Results showed that about 1500 pedestrian accidents occur in Kentucky each year and cost over $11 million. About 30 percent of pedestrian accidents in rural areas and 4 percent in urban areas are fatal. Although about 78 percent of Kentucky\u27s pedestrian accidents occur in urban areas, over 62 percent of the pedestrian fatalities occur in rural areas. Specific characteristics of pedestrian accidents were identified and related to human, environmental, and time factors. Highway and street improvements and safety programs generally considered to be effective in minimizing pedestrian accidents are summarized

Development of a Traffic Conflict Procedure for Kentucky

The objective of this report was to develop a procedure for the collection and use of traffic conflict data. Data were collected at five intersections to determine characteristics of conflicts. Observer reliability was found to be excellent. Traffic volumes accounted for only about 30 percent of the variation in numbers of conflicts. At one intersection, repeatability of conflict numbers, rates, and types was found to be very good. A total of 6,535 conflicts and 2,957 benign weaves were observed at the test sites. Based on the data, recommendations were made for collecting data during three peak hours at each site. Revised conflict data sheets were developed for signalized and nonsignalized intersections. The conflict diagram is illustrated and recommended for use. Collection of conflict data is recommended during inspections of suspected hazardous locations

Traffic Conflicts, Erratic Maneuvers, and Near-Miss Accidents: State-of-the-Art

Definitions are given for the various types of traffic conflicts, erratic maneuvers, and near-miss accidents. The General Motors technique for observation of traffic conflicts is summarized. Procedures used by several highway agencies for collecting conflict data are also detailed. Criteria which have been used to identify hazardous intersections using traffic conflict data are summarized. Methods and examples of evaluating safety improvements are detailed. Relationships between conflicts and accidents found by others were given. The procedure for observing traffic conflicts on freeway ramps is described. Definitions are given for erratic maneuvers at lane drops, gore areas, and intersections. Results from studies which utilized counts of erratic vehicle maneuvers are mentioned. The concept of near-miss accidents and the time-to-accident concept, as currently used, are explained. Advantages and limitations are given for the use of conflicts, erratic maneuvers, and near-miss accidents in identifying hazardous sites and evaluating safety improvements

Effectiveness of Green-Extension Systems at High-Speed Intersections

The purpose of this study was to determine the effectiveness of green-extension systems (GES) for reducing the dilemma-zone problem associated with the amber phase of traffic signals at high-speed intersections. Reactions of 2,100 drivers were noted during the amber phase at nine intersections, and the dilemma-zone distances with respect to the stop bar were determined. Before-and-after studies made at three green-extension sites showed a 54-percent reduction in total accidents and a 75-percent reduction in rear-end accidents after GES installation. Accident severity was unaffected. Conflict, volume, delay, and speed data were taken before and after GES installation at two sites. A 62-percent reduction in yellow-phase conflicts was noted after green extension was provided, and conflict rates decreased significantly at both sites. No significant change was found in vehicle delay due to green extension. Expected present-worth benefits due to GES installations were found to range from $29,000 to$420,000, depending on the history of rear-end accidents. Benefit-cost ratios ranged from 6 to 70

The Effectiveness of School Signs with Flashing Beacons in Reducing Vehicle Speeds

A detailed study of signs with flashers in school zones was conducted to determine their effectiveness in reducing the speeds of vehicles during times of pedestrian activity. Field investigations were conducted at all of the 120 flasher locations in Highway Districts 6, 7, and 9. About 14 percent of the flashers were inoperative. Such problems as non-uniform signing, hidden flashers, deteriorating signs and pavement markings, and poor sight distances were also found. Speed studies were conducted at 48 locations. Average speed reductions were only 3.6 mph (1.6 m/s) during flashing periods. Signs and flashers at high-speed (55-mph (25-m/s)) locations increased the potential for inter-vehicle accidents due to decreased speed uniformity. Crossing guards caused reductions in vehicle speeds to within the 25-mph (11-m/s) limit. Speed enforcement, minimal periods of flashing, good sight distance, and proper maintenance of signs and flashers were shown to improve their effectiveness in reducing speeds

Identification of Hazardous Locations on Rural Highways in Kentucky

The purpose of this study was to determine the most effective method of identifying hazardous locations for on-site investigations. To decrease the possible effect of random or spurious accidents on the identification of hazardous locations, a 0.3-mile (0.48-km) segment was chosen along with 1- and 2-year periods for accumulating and comparing accident data. An optimal method for identifying hazardous locations and sections was determined to be one which (1) maximizes benefits from improvements, (2) identifies locations with critically high accident rates, and (3) identifies potential hazards. A sample of 170 locations was used to compare several location-identification methods. The procedure recommended combines a Number Method, EPDO Method, Rate-Quality Control Method, and objective input from citizens and state police. This procedure should be used to identify hazardous spots 0.3 mile (0.48 km) long and sections 1 and 3 miles (1.61 and 4.83 km) long which should be investigated in the field. A detailed plan for implementing such a procedure is also proposed

Identification of Hazardous Locations on City Streets

The purpose of this study was to develop an effective method for identifying hazardous locations in Kentucky cities (over 2,500 population). Methods used in 45 other states were reviewed. Accident information for 69 of the 97 cities over 2,500 population was used to develop criteria for an identification method. A Number Method was selected for initial identification of midblocks and intersections on arterial-collector streets and on urban freeways. Rate-Quality Control Methods were included in the form of a critical rate factor computed for each location. A set of critical rate curves was constructed for easy determination of critical locations. A computer program ranks sites according to the criteria proposed

Cost-Effectiveness of Lane and Shoulder Widening of Rural, Two-Lane Roads in Kentucky

The purpose of the study was to determine the cost-effectiveness of widening lanes and shoulders on rural, two-lane roads. Information concerning geometries, accidents, and traffic volumes was obtained for over 15,000 miles (25,000 km) of roads. Reductions in accident rates occurred as lane and shoulder widths increased. Run-off-road and opposite direction accidents were the primary accident types associated with narrow lanes and shoulders. Reductions in accidents ranged from 10 to 39 percent for lane widening and 6 to 21 percent for shoulder widening. Priority listings were prepared for 531 projects based on critical rate factor. Priority listings were also prepared for tbe top 120 lane widening projects and the top 36 shoulder-widening projects based on benefit-cost ratios

Effect of Pavement Texture on Traffic Noise

Tire noise is one of the primary sources of highway noise, particularly at high speeds. Different types of road surfaces generate different noise levels. Noise data were collected on eight different surface types found in Kentucky. Noise measurements were made using a reference car, and noise recordings were obtained from the traffic stream. A reference truck was used for one test. It was found that portland cement concrete; Class I, Type A and A(Modified) bituminous concrete; chip seals; and open-graded, plant-mix seals were more or less normal surfaces in regard to generated noise. Sand-asphalt and Kentucky rock asphalt surfaces were about 3 dBA quieter (cars) than normal surfaces. Grooved portland cement concrete surfaces were approximately 4 dBA louder (cars) than normal surfaces. The surface type did not affect the noise emitted by trucks