{"id":2876,"date":"2019-04-01T05:00:03","date_gmt":"2019-03-31T18:00:03","guid":{"rendered":"http:\/\/www.driverknowledgetests.com\/resources\/?p=2876"},"modified":"2019-04-01T09:01:21","modified_gmt":"2019-03-31T22:01:21","slug":"how-are-roads-designed-using-the-safe-system-approach","status":"publish","type":"post","link":"https:\/\/www.driverknowledgetests.com\/resources\/how-are-roads-designed-using-the-safe-system-approach\/","title":{"rendered":"How are roads designed using the safe system approach?"},"content":{"rendered":"<p><span style=\"font-weight: 400;\">Humans are deeply flawed &#8211; far too flawed for safe driving and we see that every day in the form of crashes that result in death and injury. Our reactions are relatively slow, our eyesight is not good at night and we struggle to deal with multiple stimuli at the same time. A combination of vehicle technology and road design makes driving much safer than it otherwise would be. While we&#8217;ve covered much of the vehicle technology before (features such as automatic emergency braking and electronic stability control), road design makes up a big portion of the equation.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">A safe system acknowledges that humans make mistakes and there are four principles:<\/span><\/p>\n<ol>\n<li style=\"list-style-type: none;\">\n<ol>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Safer roads &#8211; designing roads so that they are forgiving of errors<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Safe speeds &#8211; keeping speeds to a level where any mistake is not punished by serious injury or worse<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Safer vehicles &#8211; mandating technology that is proven to reduce harm<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Safer road users &#8211; ensuring training and competence.<\/span><\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<p><span style=\"font-weight: 400;\">Preventing collisions is the first priority. Where that fails, minimising the forces the human body experiences is the second priority &#8211; by reducing them below the maximum human tolerance, survivability of accidents is increased.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The type and nature of accidents need to be considered. For example, in heavily urbanised areas, crashes between pedestrians and cyclists are more prevalent than on rural roads where accidents tend to involve the driver leaving the road or colliding with another vehicle at an intersection. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">Safe road design helps the driver make the right decisions about their driving and allows the driver to receive information about the road&#8217;s course and surface at a speed which is easy to assimilate and act on. If the driver does make a mistake, margins are built in to allow for a recovery or the roadside environment is forgiving enough to bring the vehicle to a halt without causing injury to the occupants.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">However, absolute safety can&#8217;t be guaranteed in a safe system because there are always people who will underestimate their limits.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Safe road environments are designed with five key features:<\/span><\/p>\n<ol>\n<li style=\"list-style-type: none;\">\n<ol>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Suitable for its users: urban areas will have more focus on safe pedestrian movement at the expense of vehicle speed, whereas motorways prioritise fast movement of traffic and separation from vehicles approaching in the opposite direction<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Information release is controlled: signage and road markings are delivered to the driver in a logical order and at reasonably spaced intervals so that the driver can cope with the information<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Important information is repeated: where relevant, information is given more than once to ensure that the driver is aware of an upcoming hazard, for example, a compulsory left turn at an intersection could be signposted in advance, marked on the road and also signposted at the intersection.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Design is consistent: signage and markings are predictable in relation to hazards; road widths suit the speed; bends in the road are predictable<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Transitions are obvious: road markings, signage and road characteristics are all varied consistently to indicate changes in the type or frequency of hazards and to help a driver choose an appropriate speed without the need to always be told.<\/span><\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<p><span style=\"font-weight: 400;\">While all roads are built to certain engineering standards, using those standards alone doesn&#8217;t necessarily mean the road is safe. Safe roads also:<\/span><\/p>\n<ol>\n<li style=\"list-style-type: none;\">\n<ol>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Control road users where they will come into conflict with other road users: for example, traffic lights, pedestrian crossings, direction arrows, etc<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Are self-explanatory: for example, signage that consistently directs a user to a point of interest<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Are forgiving: for example, turning bays for right turns on busy roads<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Guide road users: for example, show the direction and type of road where it might be obscured by foliage<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Warn road users: for example, give awareness of hidden features such as a sharp sequence of bends, or where ice might be a problem, or where a feature might be unexpected<\/span><\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<p><span style=\"font-weight: 400;\">Consideration is given to:<\/span><\/p>\n<ul>\n<li style=\"list-style-type: none;\">\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">The speed limit<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Vehicle speed, e.g. higher speeds need longer warning periods<\/span><\/li>\n<li style=\"font-weight: 400;\">Vehicle capability, e.g. it&#8217;s more difficult for a long vehicle to turn a sharp hairpin bend<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Visibility, e.g. the view ahead is compromised by topological features like a cliff<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Road width, e.g. road narrows going through a tunnel<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Corner angle, e.g. sharp enough to require a significant reduction in speed<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Corner characteristics, e.g. adverse camber, radius tightens<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Change in elevation, e.g. can a vehicle match the speed of other vehicles as it exits an on-ramp<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Intersection, e.g. will there be a conflict between turning vehicles and pedestrians<\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<ul>\n<li style=\"list-style-type: none;\"><\/li>\n<\/ul>\n<h2><b>Intersections<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">Intersections pose a large risk for road users. Crashes at t-intersections are common therefore is it better to have a roundabout or traffic lights to reduce risk? <\/span><\/p>\n<p><span style=\"font-weight: 400;\">The reason for and layout of a particular intersection should be obvious to a road user.<\/span><\/p>\n<h2><b>The road environment<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">While the ideal system would see road users remain on the road, this isn&#8217;t always going to happen and therefore the environment around the road has to be considered. Danger factors for road users are:<\/span><\/p>\n<ul>\n<li style=\"list-style-type: none;\">\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Heavy, non-deformable objects on the side of the road, e.g. trees, large rocks<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Steep drops, e.g. a cliff or bank<\/span><\/li>\n<li style=\"font-weight: 400;\">Street furniture, e.g. large plant pots<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Canopies, e.g. on shops<\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<ul>\n<li style=\"list-style-type: none;\">\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Vegetation that obscures views<\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">The safety of the road environment is considered in this order:<\/span><\/p>\n<ol>\n<li style=\"list-style-type: none;\">\n<ol>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Remove it: does the object even need to be there?<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Relocate it: can it be moved somewhere else?<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Redesign it to be traversed: can the object be overcome with a redesign?<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Redesign it to be frangible: can the object be changed so it is less damaging if hit<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Shield it: can a barrier be placed around it<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Warn of it: clear signage.<\/span><\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<p><span style=\"font-weight: 400;\">Using this system acknowledges that not all obstacles at the side of the road can be eliminated but the risk of them causing a problem can be mitigated.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Humans are deeply flawed &#8211; far too flawed for safe driving and we see that every day in the form of crashes that result in death and injury. Our reactions are relatively slow, our eyesight is not good at night<span class=\"ellipsis\">&hellip;<\/span><\/p>\n<div class=\"read-more\"><a href=\"https:\/\/www.driverknowledgetests.com\/resources\/how-are-roads-designed-using-the-safe-system-approach\/\">Read more &#8250;<\/a><\/div>\n<p><!-- end of .read-more --><\/p>\n","protected":false},"author":1,"featured_media":3035,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"footnotes":""},"categories":[3],"tags":[],"class_list":["post-2876","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-advice"],"_links":{"self":[{"href":"https:\/\/www.driverknowledgetests.com\/resources\/wp-json\/wp\/v2\/posts\/2876","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.driverknowledgetests.com\/resources\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.driverknowledgetests.com\/resources\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.driverknowledgetests.com\/resources\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.driverknowledgetests.com\/resources\/wp-json\/wp\/v2\/comments?post=2876"}],"version-history":[{"count":4,"href":"https:\/\/www.driverknowledgetests.com\/resources\/wp-json\/wp\/v2\/posts\/2876\/revisions"}],"predecessor-version":[{"id":3037,"href":"https:\/\/www.driverknowledgetests.com\/resources\/wp-json\/wp\/v2\/posts\/2876\/revisions\/3037"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.driverknowledgetests.com\/resources\/wp-json\/wp\/v2\/media\/3035"}],"wp:attachment":[{"href":"https:\/\/www.driverknowledgetests.com\/resources\/wp-json\/wp\/v2\/media?parent=2876"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.driverknowledgetests.com\/resources\/wp-json\/wp\/v2\/categories?post=2876"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.driverknowledgetests.com\/resources\/wp-json\/wp\/v2\/tags?post=2876"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}