This was the launch of the largest traffic management system in the world, unique in scale, complexity, and surrounding controversy. Without communications that ensured everyone knew what to do, predictions of chaos and confusion would have come true, and the 30% decrease in congestion never materialised. While high awareness was important, the campaign's critical contribution was to stimulate timely action by those affected - including over 500,000 pre-registrations for payment, discounts and exemptions, and pioneering use of texting for payment