Traffic Management and Impact Assessment PDF

TRAFFIC MANAGEMENT AND IMPACT accident analysis, keeping driver records, and ASSESSMENT other data. All traffic regulations are dependent...

TRAFFIC MANAGEMENT AND IMPACT accident analysis, keeping driver records, and ASSESSMENT other data. All traffic regulations are dependent upon the laws of the states and local governments, especially the ordinances of cities. Legislative bodies and traffic authorities must keep in mind that unreasonable restrictions or regulations are not likely to last very long. Effective Traffic Regulation INTRODUCTION There are fundamental requirements for Traffic management is a term used to traffic regulation to be effective. These are as embody the activities undertaken by a follows: highway transportation agency to improve a. Regulation should be rational. roadway system safety, efficiency and effectiveness for both providers and consumers Irrational regulations cannot be enforcing except by tremendous effort of transportation services. and expense. Social, economic, and There are two distinct types of traffic human problems must be considered. If management. The first one is through the use of traditional traffic engineering tools or simple the habits of a community are greatly at variance with the regulations, success devices to regulate and control traffic. The cannot be attained for any substantial second relies more on advanced technology period of time. through the use of Intelligent Transportation Systems (ITS). Advancement of ITS has been b. Regulations should be developed the primary goal of many developed progressively. countries. The more conventional applications Regulations must be planned are common in developing countries. over a long period of time, and the However, it is not uncommon in both effects must be carefully observed so developed and developing countries to have that alterations can be made as a combination of conventional methods and experience dictates. Experience shows ITS application. that abrupt changes in regulation often lead to increase in the occurrence of TRAFFIC REGULATIONS traffic accidents. Many individuals feel that traffic controls are an encroachment on their individual c. Regulations alone often are not driving rights. It must be stressed, however, that enough. driving is not a right but a privilege. It is Regulations constitute but one therefore necessary to show that restrictions approach to the overall traffic problem. are for the general welfare, and it must be When public acceptance is poor and demonstrated that regulations do not curtail enforcement is lax, regulations may be the rights or actions of the majority. totally ineffective. They must be used in Traffic regulation must cover all aspects conjunction with control devices, overall of the control of both vehicle (registration, highway planning and design, and ownership, mechanical fitness, accessories, administrative policies. size, and weight) and driver (age, ability to operate specific types of vehicles, financial Three Elements of the Road System responsibility). Traffic regulations must be The road system consists of the following, reasonable and effective. This can only be a. The road achieved through careful study. Facts must be b. The vehicle sought through the conduct of traffic studies, c. The driver  b. Warning devices These are used to inform road users of potentially hazardous roadway conditions or unusual traffic movements that are not readily apparent to passing traffic. c. Guiding devices These are employed simply to inform the road user of route, destination, and other pertinent traffic. Four Elementary Requirements of Every Traffic Control Device To be effective, every traffic control device The road and vehicle may be subject to must be able to meet the following constant change and improvement. However, requirements (FHWA 1988): in a given period of time, they may be a. It should compel attention. considered inflexible. The major portion of b. It should convey a simple clear meaning existing regulations is therefore aimed at the at a glance. driver. c. It should allow adequate time for easy Worldwide, licensing has become the response. most effective way of controlling the number d. It should command the respect of the of drivers on the road. It should be used, road users for whom it is intended. therefore, to influence drivers to become familiar with the rules of the road. This is Every traffic control must meet all these especially true for the Filipino drivers, requirements in logical sequence. The considering the most accidents have been effectiveness of a sign or marking normally attributed to them. For vehicles, a number of depends on its size, color contrast, shape controls exist, the most effective of which is (simple, regular shapes), relative position, and vehicle registration. Others are checks on maintenance to compel attention. To convey equipment and accessories (lights, bells, a clear meaning, the shape, color, and mirrors, helmets, etc.), and vehicle’s dimension message must be well understood. The and weight. Currently, the Motor Vehicle message should be kept as short as Inspection System (MVIS) is being revitalized practicable at a glance. After capturing the and expanded to cover the whole country. clear meaning of the device, it should provide adequate time for response. Simpler message TRAFFIC CONTROL DEVICES like STOP or YIELD requires only a second, while Traffic control devices are means by multiple choice (as in destination or guide sign) which the road user is advised as to detailed may require three to four seconds. Finally, all requirements or conditions affecting road use these requirements – the design features of size at specific places and times to that proper and brightness, position allowing time for action may be taken and accident or delay response, properly maintained control device – avoided. should command the respect of road users. There are three distinct functional Thus, shabby, ill-kept signs must be discarded groups of traffic control devices: and replaced. a. Regulatory devices These have the authority of law TRAFFIC SIGNS AND MARKINGS and impose precise requirements upon Traffic signs are employed more the actions of the road user. frequently than any other devices to regulate, warn, or guide road users. Traffic markings normally consist of lines, patterns, words, symbols, reflectors, etc. They may be considered as specialized types of traffic signs ii. Round shape shall be used for in which the message is in contrast with the regulating traffic. color and brightness of the pavement or other iii. Rectangular shape shall be used background. for informative signs. Philippine traffic signs conform to the iv. Octagonal shape shall be used 1968 Vienna Conventions of the United Nations for STOP signs only. on Road Traffic and Road Signs, which the v. Inverted equilateral triangle shall country officially adopted on June 6, 1973. be used for YIELD signs only. Traffic signs are necessary to give information as to routes, directions, Color destinations, etc. Their function becomes more i. Danger warning signs shall have a relevant when used to warn road users of yellow or white background with black hazards and regulate any prohibitive action at symbols and red border. specific places and/or at specified times. ii. Prohibitory signs and restrictive signs shall To ensure uniformity, traffic signs shall be have a white background with black installed only by a duly authorized public body symbols and red border. or official for the purpose of guiding, iii. Mandatory signs with the exception of regulating, and warning traffic. In case of STOP and YIELD signs shall have a blue temporary construction work, however, special background and white symbols. permission is given to contractors or utility iv. STOP signs shall have a red background companies to install signs to protect the public and white symbols. provided that such signs conform to the set v. YIELD signs shall have a yellow standards. background and red border. Traffic signs are normally of vi. Informative signs shall have a white or fixed/permanent type although some variable light-colored symbol on a dark-colored signs have been employed and have become (blue or black) background or a blue or useful in locations where traffic and dark-colored symbol on a white or light- environment conditions often change. colored background. Traffic signs are classified depending on their intended uses: Size a. Informative: the signs are intended to The minimum dimensions of signs guide users while they are traveling. depend upon the intended applications. b. Regulatory: the signs are intended to Larger sizes are necessary at wider roadways inform users of special obligations, and on high speed highways. According to restrictions, or prohibitions with which section 2.5 of DPWH Highway Safety Design they must comply. Standards Part 2: Road Signs and Pavement c. Warning: these signs are intended to Markings Manual, regulatory signs are of four warn users of a danger on the road and sizes based on the speed of the facility as to inform them of its nature. follows: a. A for urban low-speed roads. Elements of design b. B for rural roads with speed limits Uniformity in design includes shape, between 60 kph and 70 kph. color, dimension, symbols, wording, lettering, c. C for high-speed rural highways. and illumination. d. D for expressways. a. Shape Recommended dimensions for STOP and YIELD Shapes of signs are standardized signs. Source: DPWH (2004) as follows: SIZE DIMENSION (mm) i. Equilateral triangular shape with A 600 x 600 one side horizontal shall be used B 750 x 750 for danger warning signs. C 900 x 900 Illumination and reflectorization by visibility factor as the sign should be Signs are intended to convey messages mounted clear of vegetation and it during both daytime and night time. During must be clearly visible under headlight hours of darkness, this can be achieved illumination at night (see figure 2.2). through illumination or by using reflective On curbed roads such as in materials for signs. urban areas, the signs should be mounted at a minimum of 2 m above Placement and height of signs the top of the curb to prevent In general, signs shall be mounted obstructions to pedestrians. approximately at right angles to the direction, and facing the traffic they intended to serve. Mounting signs at exactly right angle must be avoided especially on roads following the east and west directions as the sun’s brightness reflecting on the signs will be too glaring for the drivers. However, there may be no standard location for traffic signs. Each location must be carefully studied so as to achieve the most advantageous position. Signs are generally placed on the right side of the roadway. On wider roads, overhead signs are often Figure 2.2: Height and lateral placement of necessary. On roads with medians, signs may signs. be placed on both sides. Signs may also be placed on channelized islands. c. Location of advance warning signs In urban areas, warning signs a. Lateral placement should be placed no less than 30 m but On uncurbed roads in the rural more than 100 m in advance of the areas, the sign should be at least 60 cm hazardous area, while in rural areas they clear of the outer edge of the road should be placed no less than 75 m but shoulder, the line of guideposts, or face no more than 225 m ahead of the of guardrails. The clearance should not hazardous area. The final location shall be less than 2 m nor more than 5 m from be determined based on the nature of the edge of the travelled way, except the hazard, reaction time, and for large guide signs on expressways operating speed in the area. where ample clearance may be required (see figure 2.2). In urban areas, signs should be located away from the face of the curb not less than 30 cm but not more than 1 m. If curb is mountable or semi mountable, the minimum clearance should be 50 cm. On uncurbed roads, the distance given for rural areas shall be used b. Height In rural areas, the height of the sign should normally be between 1 m and 1.5 m above the nearest edge of the travelled way. For intersection direction signs, the height should be increased to 2 m. Final height is dictated