《道路方向外文翻译英文版》由会员分享，可在线阅读，更多相关《道路方向外文翻译英文版（7页珍藏版）》请在金锄头文库上搜索。
1、I. VEHICLE AND HUMAN FACTORSThree major components affect driving: the vehicle, the roadway/environment, and the driver. In this chapter, vehicle and driver characteristics and how they are affected by the environment and physical properties of the roadway are identified. The characteristics and per
2、formance of motor vehicles play a major role in defining the fundamentals of traffic flow and capacity. Human behavior also contributes to the characteristics of traffic flow on a facility.MOTOR VEHICLE CHARACTERISTICSThis section summarizes the operating characteristics of motor vehicles that shoul
3、d be considered in analyzing a facility. The major considerations are vehicle types and dimensions, turning radii and offtracking, resistance to motion, power requirements, acceleration performance, and deceleration performance. Motor vehicles include passenger cars, trucks, vans, buses, recreationa
4、l vehicles, and motorcycles. These vehicles have unique weight, length, size, and operational characteristics. The forces that must be overcome by motor vehicles if they are to move are rolling, air, grade, curve, and inertial resistance. The weight/power ratios are useful for indicating the overall
5、 performance in overcoming these forces. Exhibit 8-1 summarizes typical motor vehicle weight and power for different vehicle types.Vehicle acceleration and deceleration rates are factors in designing traffic signaltiming, computing fuel economy and travel time values, and estimating how normaltraffi
6、c flow is resumed after a breakdown. Vehicle acceleration rates of passenger cars accelerating after a stop range between 3 and 13 ft/s2, while passenger car deceleration rates range between 7 and 26 ft/s2 (1).DRIVER CHARACTERISTICSDriving is a complex task involving a variety of skills. The most im
7、portant of these skills involve taking in and processing information and making quick decisions based on this information. Driver tasks are categorized into three main elements: control,guidance, and navigation. Control involves the drivers interaction with the vehicle in terms of speed and directio
8、n (accelerating, braking, and steering). Guidance refers to maintaining a safe path and keeping the vehicle in the proper lane. Navigation means planning and executing a trip. The perception and processing of information are important driver characteristics. About 90 percent of the information a dri
9、ver receives is visual. A significant component in the successful processing and use of information is the speed with which this processing is done. One of the parameters that is used to quantify the speed of processing information is perception-reaction time, which represents how quickly a driver c
10、an respond to an emergency situation. The parameter called sight distance is directly associated with reaction time. There are three types of sight distance: stopping, passing,and decision. This parameter is used to determine geometric features of transportation facilities.Other factors like nightti
11、me driving, fatigue, driving under the influence of alcohol and drugs, elderly drivers, and police enforcement contribute to driver behavior on a transportation facility. All these factors can affect the operational parameters of speed,delay, and density.PEDESTRIAN CHARACTERISTICSPedestrian speed is
12、 probably the most important characteristic of a pedestrian facility that is affected by individual pedestrian behavior and habit. Among several factors that influence walking speed are density, gender, size of platoon, percentage of elderly population, handicapped pedestrian population, and child p
13、edestrian population. An average walking speed of 40-ft/s is appropriate for typical groups of pedestrians. The amount of space required by a queued or standing pedestrian is 8.0 ft2. At signalized intersections pedestrian crossings must be assigned an amount of effective green time based on average
14、 walking speed.BICYCLE CHARACTERISTICSThe bicycle and the bicyclist have very different characteristics and exhibit different operation than do drivers of motor vehicles. The typical speed of bicycles is about 15 mi/h. Among other factors that affect bicycles are the type of bicycle, the bike path s
15、urface type, weather conditions, the grade of the path, and the mix of other nonmotorized users on the bike path.BUS AND LIGHT RAIL CHARACTERISTICSBus and light rail capacity are affected by vehicle type, loading area performance, and dwell time of the bus or light rail vehicle. Each bus requires a
16、certain amount of service time at stops that varies with the number of boarding and alighting passengers,door configuration, and fare collection method. The minimum safe spacing betweenbuses in motion and the number of loading areas available at any stop also influence the total number of buses and persons that a given facility can carry. The total passenger flow rate varies with bus capacity and the trade-off between se
