{"id":5306,"date":"2011-03-10T15:42:31","date_gmt":"2011-03-10T15:42:31","guid":{"rendered":"https:\/\/www.diaryofanadi.co.uk\/?p=5306"},"modified":"2011-03-10T15:42:31","modified_gmt":"2011-03-10T15:42:31","slug":"variable-speed-limit-on-m4-introduced","status":"publish","type":"post","link":"https:\/\/diaryofanadi.co.uk\/?p=5306","title":{"rendered":"Variable Speed Limit on M4 Introduced"},"content":{"rendered":"

This BBC story is interesting<\/a>. A variable speed limit has been introduced on the M4 near Newport, Wales.<\/p>\n

\"VariableOne of the things I cover with my pupils when I’m explaining the use of signals is how you can be happily driving along the motorway (or any other fast road with a lot of traffic) when, all of a sudden, the traffic in front is at a complete standstill.<\/p>\n

Ironically, it’s caused by traffic going too fast<\/em>. You know that whatever speed you’re doing, there will be dozens of people going past you at much higher speeds – most of them breaking the limit by at least 20mph. The problem is at some point they will encounter someone going slower than them. So they slow down, and perhaps change lanes to get by – this causes traffic following in any lane they use to slow down as well. As this braking is transmitted down the line, people have to slow down more and more – until someone has to stop.<\/p>\n

In the same way the braking had to get greater as it passed down the following queue, so the duration of the stop increases the further back you go. It’s quite common to end up at a complete standstill for 10 minutes or more, and then everything starts moving again and it’s like the jam never happened. Until the next time it happens further up the road.<\/p>\n

I call it the caterpillar effect, and it only happens when traffic is heavy and people are speeding or going at vastly different speeds (slow drivers can also cause it, especially if they’re in the middle or outside lanes).<\/p>\n

The BBC story points out:<\/p>\n

\n

Average speed cameras have been in operation along the stretch of the M4 since September 2009. <\/p>\n

The cameras trigger penalty notices when the 50mph limit is exceeded. <\/p>\n

More than 6,500 drivers have been issued with tickets according to figures in December 2010. <\/p>\n<\/blockquote>\n

That 6,500 is the reason there are deaths, accidents, and hold-ups on roads.<\/p>\n

The new system detects traffic flow and adjusts the maximum speed limit accordingly – something bad (and Audi) drivers are incapable of doing through sommonsense using their heads.<\/p>\n

Personally, I think it is a good idea. It won’t prevent hold-ups – but it will definitely reduce them. If it doesn’t, the government will make a shed load of money out of stupid people.<\/p>\n","protected":false},"excerpt":{"rendered":"

This BBC story is interesting. A variable speed limit has been introduced on the M4 near Newport, Wales. One of the things I cover with my pupils when I’m explaining the use of signals is how you can be happily driving along the motorway (or any other fast road with a lot of traffic) when, […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[80],"tags":[],"class_list":["post-5306","post","type-post","status-publish","format-standard","hentry","category-adi-related"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t