{"id":87,"date":"2026-07-24T18:31:20","date_gmt":"2026-07-24T18:31:20","guid":{"rendered":"https:\/\/traffic.northpetherton.org.uk\/?page_id=87"},"modified":"2026-07-24T20:06:17","modified_gmt":"2026-07-24T20:06:17","slug":"traffic-flow-explorer","status":"publish","type":"page","link":"https:\/\/traffic.northpetherton.org.uk\/?page_id=87","title":{"rendered":"Traffic Flow Explorer"},"content":{"rendered":"<div data-colibri-id=\"87-c1\" class=\"style-339 style-local-87-c1 position-relative\">\n  <!---->\n  <div data-colibri-component=\"section\" data-colibri-id=\"87-c2\" id=\"custom-2\" class=\"h-section h-section-global-spacing d-flex align-items-lg-center align-items-md-center align-items-center style-345 style-local-87-c2 position-relative\">\n    <!---->\n    <!---->\n    <div class=\"h-section-grid-container h-section-boxed-container\">\n      <!---->\n      <div data-colibri-id=\"87-c3\" class=\"h-row-container gutters-row-lg-2 gutters-row-md-2 gutters-row-0 gutters-row-v-lg-2 gutters-row-v-md-2 gutters-row-v-2 style-346 style-local-87-c3 position-relative\">\n        <!---->\n        <div class=\"h-row justify-content-lg-center justify-content-md-center justify-content-center align-items-lg-stretch align-items-md-stretch align-items-stretch gutters-col-lg-2 gutters-col-md-2 gutters-col-0 gutters-col-v-lg-2 gutters-col-v-md-2 gutters-col-v-2\">\n          <!---->\n          <div class=\"h-column h-column-container d-flex h-col-lg-auto h-col-md-auto h-col-auto style-347-outer style-local-87-c4-outer\">\n            <div data-colibri-id=\"87-c4\" class=\"d-flex h-flex-basis h-column__inner h-px-lg-2 h-px-md-2 h-px-2 v-inner-lg-2 v-inner-md-2 v-inner-2 style-347 style-local-87-c4 position-relative\">\n              <!---->\n              <!---->\n              <div class=\"w-100 h-y-container h-column__content h-column__v-align flex-basis-100 align-self-lg-start align-self-md-start align-self-start\">\n                <!---->\n                <div data-colibri-id=\"87-c5\" class=\"style-348 style-local-87-c5 position-relative h-element\">\n                  <!---->\n                  <div class=\"\">\t\t<section\n\t\t\tid=\"nptraffic-1-6916\"\n\t\t\tclass=\"nptraffic\"\n\t\t\tdata-nptraffic-instance\n\t\t\tdata-capacity=\"1276\"\n\t\t\tdata-start-minutes=\"1020\"\n\t\t\tdata-baseline=\"2021\"\n\t\t\tdata-development=\"80\"\n\t\t\tdata-p30=\"100\"\n\t\t\tstyle=\"--nptraffic-map-height: 620px\"\n\t\t>\n\t\t\t<header class=\"nptraffic__header\">\n\t\t\t\t<div>\n\t\t\t\t\t<p class=\"nptraffic__eyebrow\">Published counts \u00b7 interactive scenario model<\/p>\n\t\t\t\t\t<h2 class=\"nptraffic__title\">A38 North Petherton traffic flow explorer<\/h2>\n\t\t\t\t\t<p class=\"nptraffic__intro\">\n\t\t\t\t\t\tExplore how the measured vehicle mix and user-defined changes affect estimated flow, capacity, speed and delay on the indicative A38 30 mph town section.\t\t\t\t\t<\/p>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"nptraffic__data-stamp\" aria-label=\"Data status\">\n\t\t\t\t\t<span class=\"nptraffic__pill nptraffic__pill--source\">DfT point 16378<\/span>\n\t\t\t\t\t<span class=\"nptraffic__pill\" data-field=\"baseline-badge\">2021 counted<\/span>\n\t\t\t\t\t<span class=\"nptraffic__pill nptraffic__pill--speed\">30 mph<\/span>\n\t\t\t\t<\/div>\n\t\t\t<\/header>\n\n\t\t\t<div class=\"nptraffic__notice\" role=\"note\">\n\t\t\t\t<strong>Scenario tool, not live traffic:<\/strong>\n\t\t\t\tthe 2021 option uses observed hourly counts; the 2025 option is an explicitly labelled AADF-scaled estimate. Incidents, roadworks, weather and detailed junction queues are not included.\t\t\t<\/div>\n\n\t\t\t<div class=\"nptraffic__workspace\">\n\t\t\t\t<div class=\"nptraffic__map-column\">\n\t\t\t\t\t<div class=\"nptraffic__map-shell\">\n\t\t\t\t\t\t<div class=\"nptraffic__map\" data-role=\"map\" role=\"region\" aria-label=\"Interactive map of the indicative A38 route through North Petherton\"><\/div>\n\t\t\t\t\t\t<div class=\"nptraffic__map-overlay\" aria-hidden=\"true\">\n\t\t\t\t\t\t\t<span><i class=\"nptraffic__legend-line\"><\/i>Indicative modelled section<\/span>\n\t\t\t\t\t\t\t<span><i class=\"nptraffic__legend-dot\"><\/i>DfT count point<\/span>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<p class=\"nptraffic__map-caption\">\n\t\t\t\t\t\tThe line is an indicative centreline for visualisation. Posted signs and traffic regulation orders determine the legal speed-limit boundary.\t\t\t\t\t<\/p>\n\t\t\t\t<\/div>\n\n\t\t\t\t<aside class=\"nptraffic__controls\" aria-labelledby=\"nptraffic-1-6916-controls-title\">\n\t\t\t\t\t<div class=\"nptraffic__controls-heading\">\n\t\t\t\t\t\t<div>\n\t\t\t\t\t\t\t<p class=\"nptraffic__kicker\">Scenario controls<\/p>\n\t\t\t\t\t\t\t<h3 id=\"nptraffic-1-6916-controls-title\">Change time and traffic mix<\/h3>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<button type=\"button\" class=\"nptraffic__reset\" data-action=\"reset\">Reset<\/button>\n\t\t\t\t\t<\/div>\n\n\t\t\t\t\t<div class=\"nptraffic__control nptraffic__control--time\">\n\t\t\t\t\t\t<div class=\"nptraffic__control-label-row\">\n\t\t\t\t\t\t\t<label for=\"nptraffic-1-6916-time\">Time of day<\/label>\n\t\t\t\t\t\t\t<output for=\"nptraffic-1-6916-time\" data-output=\"time\">17:00<\/output>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<input id=\"nptraffic-1-6916-time\" data-control=\"time\" type=\"range\" min=\"420\" max=\"1080\" step=\"15\" value=\"1020\">\n\t\t\t\t\t\t<div class=\"nptraffic__range-ends\"><span>07:00<\/span><span>18:00<\/span><\/div>\n\t\t\t\t\t\t<p class=\"nptraffic__hint\" data-field=\"time-data-note\">Exact DfT hourly count<\/p>\n\t\t\t\t\t<\/div>\n\n\t\t\t\t\t<div class=\"nptraffic__control\">\n\t\t\t\t\t\t<label for=\"nptraffic-1-6916-baseline\">Data baseline<\/label>\n\t\t\t\t\t\t<select id=\"nptraffic-1-6916-baseline\" data-control=\"baseline\">\n\t\t\t\t\t\t\t<option value=\"2021\"  selected='selected'>2021 counted hourly profile<\/option>\n\t\t\t\t\t\t\t<option value=\"2025\" >2025 DfT estimated AADF-scaled profile<\/option>\n\t\t\t\t\t\t<\/select>\n\t\t\t\t\t\t<p class=\"nptraffic__hint\" data-field=\"baseline-note\"><\/p>\n\t\t\t\t\t<\/div>\n\n\t\t\t\t\t<fieldset class=\"nptraffic__vehicle-fieldset\">\n\t\t\t\t\t\t<legend>Vehicle scenario multipliers<\/legend>\n\t\t\t\t\t\t<p class=\"nptraffic__hint\">100% keeps the selected baseline. HGVs have a larger passenger-car-unit effect in the capacity model.<\/p>\n\n\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"nptraffic__control nptraffic__control--vehicle\">\n\t\t\t\t\t\t\t\t<div class=\"nptraffic__control-label-row\">\n\t\t\t\t\t\t\t\t\t<label for=\"nptraffic-1-6916-cars\">Cars and taxis<\/label>\n\t\t\t\t\t\t\t\t\t<output for=\"nptraffic-1-6916-cars\" data-output=\"cars\">100%<\/output>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<input id=\"nptraffic-1-6916-cars\" data-control=\"cars\" type=\"range\" min=\"0\" max=\"300\" step=\"5\" value=\"100\">\n\t\t\t\t\t\t\t\t<div class=\"nptraffic__range-ends\"><span>0%<\/span><span>300%<\/span><\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"nptraffic__control nptraffic__control--vehicle\">\n\t\t\t\t\t\t\t\t<div class=\"nptraffic__control-label-row\">\n\t\t\t\t\t\t\t\t\t<label for=\"nptraffic-1-6916-vans\">Vans \/ LGVs<\/label>\n\t\t\t\t\t\t\t\t\t<output for=\"nptraffic-1-6916-vans\" data-output=\"vans\">100%<\/output>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<input id=\"nptraffic-1-6916-vans\" data-control=\"vans\" type=\"range\" min=\"0\" max=\"300\" step=\"5\" value=\"100\">\n\t\t\t\t\t\t\t\t<div class=\"nptraffic__range-ends\"><span>0%<\/span><span>300%<\/span><\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"nptraffic__control nptraffic__control--vehicle\">\n\t\t\t\t\t\t\t\t<div class=\"nptraffic__control-label-row\">\n\t\t\t\t\t\t\t\t\t<label for=\"nptraffic-1-6916-hgvs\">HGVs<\/label>\n\t\t\t\t\t\t\t\t\t<output for=\"nptraffic-1-6916-hgvs\" data-output=\"hgvs\">100%<\/output>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<input id=\"nptraffic-1-6916-hgvs\" data-control=\"hgvs\" type=\"range\" min=\"0\" max=\"300\" step=\"5\" value=\"100\">\n\t\t\t\t\t\t\t\t<div class=\"nptraffic__range-ends\"><span>0%<\/span><span>300%<\/span><\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t<\/fieldset>\n\t\t\t\t<\/aside>\n\t\t\t<\/div>\n\n\t\t\t<div class=\"nptraffic__results\" aria-labelledby=\"nptraffic-1-6916-results-title\">\n\t\t\t\t<div class=\"nptraffic__results-heading\">\n\t\t\t\t\t<div>\n\t\t\t\t\t\t<p class=\"nptraffic__kicker\">Modelled result<\/p>\n\t\t\t\t\t\t<h3 id=\"nptraffic-1-6916-results-title\">Busiest-direction road conditions<\/h3>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<span class=\"nptraffic__status\" data-field=\"status-badge\">\u2014<\/span>\n\t\t\t\t<\/div>\n\n\t\t\t\t<div class=\"nptraffic__metrics\">\n\t\t\t\t\t<div class=\"nptraffic__metric\">\n\t\t\t\t\t\t<span class=\"nptraffic__metric-label\">Two-way traffic<\/span>\n\t\t\t\t\t\t<strong><span data-field=\"total-flow\">\u2014<\/span> <small>veh\/h<\/small><\/strong>\n\t\t\t\t\t\t<span class=\"nptraffic__metric-sub\" data-field=\"vehicle-mix\">\u2014<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"nptraffic__metric nptraffic__metric--capacity\">\n\t\t\t\t\t\t<span class=\"nptraffic__metric-label\">Capacity used<\/span>\n\t\t\t\t\t\t<strong><span data-field=\"capacity-percent\">\u2014<\/span><small>%<\/small><\/strong>\n\t\t\t\t\t\t<span class=\"nptraffic__metric-sub\" data-field=\"capacity-headroom\">\u2014<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"nptraffic__metric\">\n\t\t\t\t\t\t<span class=\"nptraffic__metric-label\">Likelihood of material delay<\/span>\n\t\t\t\t\t\t<strong><span data-field=\"likelihood-label\">\u2014<\/span><\/strong>\n\t\t\t\t\t\t<span class=\"nptraffic__metric-sub\"><span data-field=\"likelihood-percent\">\u2014<\/span>% modelled indicator<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"nptraffic__metric\">\n\t\t\t\t\t\t<span class=\"nptraffic__metric-label\">Estimated added time<\/span>\n\t\t\t\t\t\t<strong data-field=\"delay-time\">\u2014<\/strong>\n\t\t\t\t\t\t<span class=\"nptraffic__metric-sub\"><span data-field=\"journey-time\">\u2014<\/span> journey \u00b7 <span data-field=\"speed\">\u2014<\/span> mph<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\n\t\t\t\t<div class=\"nptraffic__capacity-panel\">\n\t\t\t\t\t<div class=\"nptraffic__capacity-labels\">\n\t\t\t\t\t\t<span>Busiest-direction capacity<\/span>\n\t\t\t\t\t\t<strong data-field=\"capacity-detail\">\u2014<\/strong>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"nptraffic__capacity-track\" role=\"progressbar\" aria-label=\"Busiest-direction capacity used\" aria-valuemin=\"0\" aria-valuemax=\"150\" aria-valuenow=\"0\" data-role=\"capacity-progress\">\n\t\t\t\t\t\t<div class=\"nptraffic__capacity-fill\" data-role=\"capacity-fill\"><\/div>\n\t\t\t\t\t\t<span class=\"nptraffic__capacity-marker nptraffic__capacity-marker--80\" aria-hidden=\"true\">80%<\/span>\n\t\t\t\t\t\t<span class=\"nptraffic__capacity-marker nptraffic__capacity-marker--100\" aria-hidden=\"true\">100%<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<p class=\"nptraffic__summary\" data-field=\"summary\" aria-live=\"polite\"><\/p>\n\t\t\t\t<\/div>\n\n\t\t\t\t<div class=\"nptraffic__direction-grid\">\n\t\t\t\t\t<div class=\"nptraffic__direction-card\" data-direction-card=\"northbound\">\n\t\t\t\t\t\t<h4>Northbound<\/h4>\n\t\t\t\t\t\t<dl>\n\t\t\t\t\t\t\t<div><dt>Flow<\/dt><dd data-direction=\"northbound\" data-value=\"flow\">\u2014<\/dd><\/div>\n\t\t\t\t\t\t\t<div><dt>PCU flow<\/dt><dd data-direction=\"northbound\" data-value=\"pcu\">\u2014<\/dd><\/div>\n\t\t\t\t\t\t\t<div><dt>Capacity<\/dt><dd data-direction=\"northbound\" data-value=\"capacity\">\u2014<\/dd><\/div>\n\t\t\t\t\t\t\t<div><dt>Est. speed<\/dt><dd data-direction=\"northbound\" data-value=\"speed\">\u2014<\/dd><\/div>\n\t\t\t\t\t\t\t<div><dt>Added time<\/dt><dd data-direction=\"northbound\" data-value=\"delay\">\u2014<\/dd><\/div>\n\t\t\t\t\t\t<\/dl>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"nptraffic__direction-card\" data-direction-card=\"southbound\">\n\t\t\t\t\t\t<h4>Southbound<\/h4>\n\t\t\t\t\t\t<dl>\n\t\t\t\t\t\t\t<div><dt>Flow<\/dt><dd data-direction=\"southbound\" data-value=\"flow\">\u2014<\/dd><\/div>\n\t\t\t\t\t\t\t<div><dt>PCU flow<\/dt><dd data-direction=\"southbound\" data-value=\"pcu\">\u2014<\/dd><\/div>\n\t\t\t\t\t\t\t<div><dt>Capacity<\/dt><dd data-direction=\"southbound\" data-value=\"capacity\">\u2014<\/dd><\/div>\n\t\t\t\t\t\t\t<div><dt>Est. speed<\/dt><dd data-direction=\"southbound\" data-value=\"speed\">\u2014<\/dd><\/div>\n\t\t\t\t\t\t\t<div><dt>Added time<\/dt><dd data-direction=\"southbound\" data-value=\"delay\">\u2014<\/dd><\/div>\n\t\t\t\t\t\t<\/dl>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t<\/div>\n\n\t\t\t\t\t\t\t<details class=\"nptraffic__methodology\">\n\t\t\t\t\t<summary>How the data and estimates are calculated<\/summary>\n\t\t\t\t\t<div class=\"nptraffic__methodology-content\">\n\t\t\t\t\t\t<div>\n\t\t\t\t\t\t\t<h3>Measured baseline<\/h3>\n\t\t\t\t\t\t\t<p>The hourly profile is the DfT manual count at count point 16378 on 5 May 2021. The published 2021 AADF is 15,697 motor vehicles per day. DfT\u2019s 2025 value is 17,663 and is marked as estimated; the 2025 option scales each 2021 hourly vehicle class by the corresponding AADF change.<\/p>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<div>\n\t\t\t\t\t\t\t<h3>Capacity and speed<\/h3>\n\t\t\t\t\t\t\t<p>The default screening capacity is <strong>1,276<\/strong> PCU\/hour in each direction. It converts WebTAG\u2019s 1,200 vehicles\/hour small-town reference capacity using the counted 2021 heavy-vehicle share at this DfT point. Cars, vans and motorcycles count as 1 PCU; HGVs and buses count as 2. Speed is estimated with the WebTAG Unit M3.1 small-town relationship, using 80% frontage development and 100% of this modelled section in a 30 mph limit.<\/p>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<div>\n\t\t\t\t\t\t\t<h3>Delay and likelihood<\/h3>\n\t\t\t\t\t\t\t<p>Added time is the difference between the modelled journey and the model\u2019s zero-flow journey over the indicative 2.70 km section. Above capacity, WebTAG\u2019s one-hour over-capacity delay relationship is applied. The percentage likelihood is a transparent logistic indicator derived from the volume-to-capacity ratio; it is not an observed probability.<\/p>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<div>\n\t\t\t\t\t\t\t<h3>Limits of use<\/h3>\n\t\t\t\t\t\t\t<p>This is a corridor screening and engagement tool. The hourly shape comes from one manual-count day in 2021 and should not be treated as every weekday or current live conditions. It does not include live incidents, roadworks, weather, school-day variation, turning movements, signal timings or detailed queue interaction at junctions. It should not be used for navigation, enforcement or engineering design.<\/p>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<p class=\"nptraffic__sources\">\n\t\t\t\t\t\t\t<a href=\"https:\/\/roadtraffic.dft.gov.uk\/count-points\/16378\" target=\"_blank\" rel=\"noopener noreferrer\">DfT count point 16378<\/a>\n\t\t\t\t\t\t\t<span aria-hidden=\"true\">\u00b7<\/span>\n\t\t\t\t\t\t\t<a href=\"https:\/\/www.gov.uk\/government\/publications\/tag-unit-m3-1-highway-assignment-modelling\" target=\"_blank\" rel=\"noopener noreferrer\">WebTAG Unit M3.1<\/a>\n\t\t\t\t\t\t\t<span aria-hidden=\"true\">\u00b7<\/span>\n\t\t\t\t\t\t\t<a href=\"https:\/\/www.nationalarchives.gov.uk\/doc\/open-government-licence\/version\/3\/\" target=\"_blank\" rel=\"noopener noreferrer\">Open Government Licence v3.0<\/a>\n\t\t\t\t\t\t<\/p>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/details>\n\t\t\t\n\t\t\t<noscript><p class=\"nptraffic__error\">JavaScript is required to operate the traffic scenario controls.<\/p><\/noscript>\n\t\t<\/section>\n\t\t<\/div>\n                <\/div>\n              <\/div>\n            <\/div>\n          <\/div>\n        <\/div>\n      <\/div>\n    <\/div>\n  <\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"page-templates\/full-width-page.php","meta":{"footnotes":""},"class_list":["post-87","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/traffic.northpetherton.org.uk\/index.php?rest_route=\/wp\/v2\/pages\/87","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/traffic.northpetherton.org.uk\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/traffic.northpetherton.org.uk\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/traffic.northpetherton.org.uk\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/traffic.northpetherton.org.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=87"}],"version-history":[{"count":6,"href":"https:\/\/traffic.northpetherton.org.uk\/index.php?rest_route=\/wp\/v2\/pages\/87\/revisions"}],"predecessor-version":[{"id":148,"href":"https:\/\/traffic.northpetherton.org.uk\/index.php?rest_route=\/wp\/v2\/pages\/87\/revisions\/148"}],"wp:attachment":[{"href":"https:\/\/traffic.northpetherton.org.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=87"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}