1.0Sightline Institutehttps://www.sightline.orgClark Williams-Derryhttps://www.sightline.org/profile/clark-williams-derry/rich600338<blockquote class="wp-embedded-content" data-secret="vloGayznLn"><a href="https://www.sightline.org/2012/09/10/sr-520-a-victim-of-bad-forecasting/">SR-520: A Case of Bad Forecasting?</a></blockquote><iframe sandbox="allow-scripts" security="restricted" src="https://www.sightline.org/2012/09/10/sr-520-a-victim-of-bad-forecasting/embed/#?secret=vloGayznLn" width="600" height="338" title="“SR-520: A Case of Bad Forecasting?” — Sightline Institute" data-secret="vloGayznLn" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" class="wp-embedded-content"></iframe><script type="text/javascript"> /* <![CDATA[ */ /*! This file is auto-generated */ !function(d,l){"use strict";l.querySelector&&d.addEventListener&&"undefined"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!/[^a-zA-Z0-9]/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret="'+t.secret+'"]'),o=l.querySelectorAll('blockquote[data-secret="'+t.secret+'"]'),c=new RegExp("^https?:$","i"),i=0;i<o.length;i++)o[i].style.display="none";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute("style"),"height"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):"link"===t.message&&(r=new URL(s.getAttribute("src")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener("message",d.wp.receiveEmbedMessage,!1),l.addEventListener("DOMContentLoaded",function(){for(var e,t,s=l.querySelectorAll("iframe.wp-embedded-content"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute("data-secret"))||(t=Math.random().toString(36).substring(2,12),e.src+="#?secret="+t,e.setAttribute("data-secret",t)),e.contentWindow.postMessage({message:"ready",secret:t},"*")},!1)))}(window,document); /* ]]> */ </script> https://www.sightline.org/wp-content/uploads/2012/09/520-bridge-traffic2.png460420Here’s a blast from the past: WSDOT’S early forecasts, dating from 2002, for SR-520 traffic after tolling was scheduled to start. Depending on the tolling scenario, they predicted that the floating bridge would carry between 90,000 and 98,000 cars per day in the first year of tolling, down from a baseline of 118,000 cars per day with no tolling. (The report isn’t available online, so click for the full-sized scanned version of the chart.) The reality for January through June: an average of 63,500 cars on weekdays, down from a baseline of 101,100 weekday cars the prior fall. When you include weekends as well, the trends are even more striking: