{"id":222384,"date":"2025-05-31T09:53:02","date_gmt":"2025-05-31T09:53:02","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=222384"},"modified":"2025-05-31T09:53:04","modified_gmt":"2025-05-31T09:53:04","slug":"find-the-peak-hour-volume-peak-hour-factor-phf-and-the-actual-or-design-flow-rate-for-an-existing-one-lane-approach","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/31\/find-the-peak-hour-volume-peak-hour-factor-phf-and-the-actual-or-design-flow-rate-for-an-existing-one-lane-approach\/","title":{"rendered":"Find the peak hour volume, peak hour factor (PHF), and the actual or design flow rate for an existing one-lane approach."},"content":{"rendered":"\n

Find the peak hour volume, peak hour factor (PHF), and the actual or design flow rate for an existing one-lane approach. To do this, you obtain a click-counter and position yourself at the intersection. For each fifteen-minute interval, you record the numbers of right-turns, left-turns, straight-through trucks, and straight-through passenger cars. Your tabulated values are as shown below. If a truck is equal to 1.5 passenger cars and a right-turn is as well, and if a left-turn is equal to 2.5 passenger cars, then calculate the peak hour volume, peak hour factor (PHF), and the actual (design) flow rate for this approach.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n

Step-by-Step Solution<\/strong><\/h3>\n\n\n\n

Step 1: Convert all vehicles to Passenger Car Equivalents (PCE)<\/strong><\/h4>\n\n\n\n

Given:<\/p>\n\n\n\n

    \n
  • 1 Truck = 1.5 Passenger Cars<\/li>\n\n\n\n
  • 1 Right Turn = 1.5 Passenger Cars<\/li>\n\n\n\n
  • 1 Left Turn = 2.5 Passenger Cars<\/li>\n<\/ul>\n\n\n\n

    We calculate the total PCE for each 15-minute interval:<\/p>\n\n\n\n

    Interval<\/th>Left Turns (\u00d72.5)<\/th>Right Turns (\u00d71.5)<\/th>ST Trucks (\u00d71.5)<\/th>ST Cars<\/th>Total PCE<\/th><\/tr><\/thead>
    4:00\u20134:15<\/td>5\u00d72.5 = 12.5<\/td>10\u00d71.5 = 15.0<\/td>7\u00d71.5 = 10.5<\/td>35<\/td>73.0<\/strong><\/td><\/tr>
    4:15\u20134:30<\/td>6\u00d72.5 = 15.0<\/td>15\u00d71.5 = 22.5<\/td>9\u00d71.5 = 13.5<\/td>26<\/td>77.0<\/strong><\/td><\/tr>
    4:30\u20134:45<\/td>4\u00d72.5 = 10.0<\/td>7\u00d71.5 = 10.5<\/td>11\u00d71.5 = 16.5<\/td>39<\/td>76.0<\/strong><\/td><\/tr>
    4:45\u20135:00<\/td>7\u00d72.5 = 17.5<\/td>16\u00d71.5 = 24.0<\/td>9\u00d71.5 = 13.5<\/td>42<\/td>97.0<\/strong><\/td><\/tr>
    5:00\u20135:15<\/td>10\u00d72.5 = 25.0<\/td>13\u00d71.5 = 19.5<\/td>7\u00d71.5 = 10.5<\/td>55<\/td>110.0<\/strong><\/td><\/tr>
    5:15\u20135:30<\/td>9\u00d72.5 = 22.5<\/td>12\u00d71.5 = 18.0<\/td>13\u00d71.5 = 19.5<\/td>68<\/td>128.0<\/strong><\/td><\/tr>
    5:30\u20135:45<\/td>14\u00d72.5 = 35.0<\/td>16\u00d71.5 = 24.0<\/td>10\u00d71.5 = 15.0<\/td>72<\/td>146.0<\/strong><\/td><\/tr>
    5:45\u20136:00<\/td>12\u00d72.5 = 30.0<\/td>13\u00d71.5 = 19.5<\/td>9\u00d71.5 = 13.5<\/td>41<\/td>104.0<\/strong><\/td><\/tr>
    6:15\u20136:30<\/td>10\u00d72.5 = 25.0<\/td>10\u00d71.5 = 15.0<\/td>4\u00d71.5 = 6.0<\/td>35<\/td>81.0<\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

    Step 2: Identify Peak Hour<\/strong><\/h4>\n\n\n\n

    We now sum 4 consecutive intervals (1 hour):<\/p>\n\n\n\n

      \n
    • 4:00\u20135:00 \u2192 73 + 77 + 76 + 97 = 323<\/strong><\/li>\n\n\n\n
    • 4:15\u20135:15 \u2192 77 + 76 + 97 + 110 = 360<\/strong><\/li>\n\n\n\n
    • 4:30\u20135:30 \u2192 76 + 97 + 110 + 128 = 411<\/strong><\/li>\n\n\n\n
    • 4:45\u20135:45 \u2192 97 + 110 + 128 + 146 = 481<\/strong> \u2b05\ufe0f Peak Hour<\/strong><\/li>\n\n\n\n
    • 5:00\u20136:00 \u2192 110 + 128 + 146 + 104 = 488<\/strong> \u2b05\ufe0f Peak Hour (MAX)<\/strong><\/li>\n\n\n\n
    • 5:15\u20136:15 \u2192 128 + 146 + 104 + 81 = 459<\/strong><\/li>\n<\/ul>\n\n\n\n

      \u2705 Peak Hour Volume = 488 PCE<\/strong><\/p>\n\n\n\n

      Step 3: Calculate PHF (Peak Hour Factor)<\/strong><\/h4>\n\n\n\n

      PHF=Total Volume in Peak Hour4\u00d7Highest 15-min Volume in Peak Hour\\text{PHF} = \\frac{\\text{Total Volume in Peak Hour}}{4 \\times \\text{Highest 15-min Volume in Peak Hour}}<\/p>\n\n\n\n

      In peak hour 5:00\u20136:00, the 15-min volumes are:<\/p>\n\n\n\n

        \n
      • 110, 128, 146, 104 \u2192 Max = 146<\/li>\n<\/ul>\n\n\n\n

        PHF=4884\u00d7146=488584\u22480.8356\\text{PHF} = \\frac{488}{4 \\times 146} = \\frac{488}{584} \\approx 0.8356<\/p>\n\n\n\n

        Step 4: Calculate Design Flow Rate (v)<\/strong><\/h4>\n\n\n\n

        v=Peak Hour VolumePHF\u00d71 hour=4880.8356\u2248584.1 PCE\/hourv = \\frac{\\text{Peak Hour Volume}}{\\text{PHF} \\times 1 \\text{ hour}} = \\frac{488}{0.8356} \\approx 584.1 \\text{ PCE\/hour}<\/p>\n\n\n\n

        \n\n\n\n

        Final Answers<\/strong><\/h3>\n\n\n\n
          \n
        • Peak Hour Volume:<\/strong> 488 PCE<\/li>\n\n\n\n
        • PHF:<\/strong> 0.836<\/li>\n\n\n\n
        • Design Flow Rate:<\/strong> 584 PCE\/hour<\/li>\n<\/ul>\n\n\n\n
          \n\n\n\n

          Explanation<\/strong><\/h3>\n\n\n\n

          The peak hour volume, peak hour factor (PHF), and design flow rate are key metrics used in traffic analysis to evaluate the performance of a roadway segment, especially at intersections. These values help engineers determine whether the current infrastructure meets traffic demand or if improvements are needed.<\/p>\n\n\n\n

          To begin, we collected traffic counts over 15-minute intervals, recording the number of vehicles by type and movement. However, not all vehicles affect traffic flow equally; for example, trucks and turning vehicles often take more time and space. To account for this, we convert each vehicle type to Passenger Car Equivalents (PCE)<\/strong> using industry-standard factors: trucks and right-turns count as 1.5 PCE, while left-turns are 2.5 PCE due to their higher disruption potential.<\/p>\n\n\n\n

          Next, we calculate the total PCE for each 15-minute interval. We then sum four consecutive intervals to determine the peak hour<\/strong> \u2014 the hour with the highest total PCE. In this case, the interval from 5:00\u20136:00 PM had the highest volume: 488 PCE.<\/p>\n\n\n\n

          The PHF<\/strong> measures the variability of traffic flow within the peak hour. A PHF of 1.0 indicates uniform flow; lower values signal more peaked demand. It is calculated by dividing the total peak hour volume by four times the highest 15-minute interval volume. Our PHF of 0.836 suggests notable peaking behavior, meaning most traffic is concentrated in a short burst.<\/p>\n\n\n\n

          Finally, the design flow rate<\/strong> is the adjusted traffic flow used for designing the lane, incorporating peaking by dividing the peak hour volume by the PHF. This yields 584 PCE\/hour \u2014 the true load the lane should be able to accommodate.<\/p>\n\n\n\n

          \"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

          Find the peak hour volume, peak hour factor (PHF), and the actual or design flow rate for an existing one-lane approach. To do this, you obtain a click-counter and position yourself at the intersection. For each fifteen-minute interval, you record the numbers of right-turns, left-turns, straight-through trucks, and straight-through passenger cars. Your tabulated values are […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-222384","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/222384","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=222384"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/222384\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=222384"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=222384"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=222384"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}