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COPY -NCDOT <br />IV. EXISTING TRAFFIC CONDITIONS IN COUNTY <br />Capacity, Width, and Alignment Deficiencies <br />Due to the increase in population and number of registered <br />vehicles in Orange County over the past decades, some of the roads <br />built in the past and not recently repaired may not withstand the <br />anticipated load of cars using these roads. Capacity, width, and <br />alignment designs with which they were built may limit their <br />potential to facilitate this demand. Land use plays a part in the <br />"erosion" of these roads. As land develops the road serving this <br />land may become inadequate due to the increased usage. <br />Depending on the factors mentioned above, the design <br />requirements for thoroughfares vary. Using general design <br />requirements for roads is undesirable, due to the different land <br />uses, population amounts, and traffic volumes that can occur along <br />different sections of a given thoroughfare. Each section of a <br />given road must be individually analyzed and its design <br />requirements determined on the basis of amount and type of <br />projected traffic, existing capacity,-desired levels of service, <br />and available right -of -way. <br />The term level of service denotes any of an infinite number <br />of differing combinations of operating conditions that can occur <br />on a given lane or roadway when it is accommodating various <br />traffic volumes.(1) Six levels of service exist (levels A through <br />F, shown in Figure 5), which, by using effects from such factors <br />as travel time, speed, cost, and maneuverability, determine the <br />type of service that the thoroughfare gives to the motorist under <br />the stated conditions. The six levels are defined as follows: <br />1) Level A: free flow at low densities with no restrictions <br />due to traffic conditions. <br />2) Level B: stable <br />driver freedom. <br />rural highways. <br />3) Level C: stable <br />on the driver's <br />ability to pass. <br />flow with some slight restriction of <br />This is often used for the design of <br />flow with increased marked restriction <br />selection of speed and with reduced <br />4) Level D: decreased flow with little freedom for driver <br />maneuverability. The operating speeds are still <br />tolerable; however, this region approaches the condition <br />of unstable flow. <br />1 Highway Engineering (4e) , Wright & Paquette, pg. 126, <br />1979. <br />19 <br />