International Conference on Road Safety in Africa A

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Current trends in urban & rural road safety engineering The African Perspective by Clive Sawers M. A. M. I. C. E. CEng. Traffic Engineering Consultant, UK Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Additional Material for viewing This is the presentation that I made at Abuja on Monday 18 February 2008 I have added explanatory text to the slides to complement the text, images and graphics that you will see as you progress through the presentation. In general I suggest that you read first these text additions that appear on most of the slides; they are all in black (or occasionally white) Times New Roman font style. This presentation is offered for download free but must not be copied, amended or otherwise altered in any way without the express permission of the author. Similarly the advice given is based on experience but no liability can be accepted for any errors or omissions. Design Engineers and any others who wish to make use of the advice given in this presentation must satisfy themselves that it will be applied appropriately and should apply all precautions. Clive Sawers MA MICE CEng March 2008 Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering The Culture of Road Safety – the 5 Es! • Education • ENTHUSIASM! • Children road safety education • Driving instruction and tests • Engineering • Better design – roads & layouts • Better design - vehicles • Safety audits • Enforcement • Police presence/FRSC • Cameras • • Road Safety Professionals Conferences & Seminars Publications Other training, liaison, forums etc… • A PASSION for Road Safety During the course of the conference there were several “Es” added to the list! But the three main ones of road safety are Education, Enforcement and Engineering. This presentation is based mainly on Engineering. • Emergency Services • Fire & Rescue • Ambulance Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering In this presentation I shall demonstrate that: • In the urban environment • • • continuity of footway/sidewalk important Roundabouts create safe intersection facilities Roundabout splitter islands work for pedestrians and cyclists extending the splitter island creates a long median/refuge Speed tables can fill all the gaps between roundabouts if needed • In the rural environment • Single two-way main roads with roundabouts can be safe • And what their risks are • Divided highways can be made safe • And what their risks are • Incomplete routes comprising both divided and two-way roadways • Special problems to be avoided Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering What’s wrong with signals? • Signals and pedestrian facilities are not as safe as they should be • • • Costs • • High severity ratio (proportion of accidents with serious injuries) Turning or right angle crashes (usually serious) Pedestrian accidents feature at signals usually serious Turns often banned – U-turning impossible May cost slightly less to install signal than roundabout initially Shorter life-span Ongoing maintenance Failures • • Breakdown Power supply – these are serious problems here… [in Abuja & the rest of Nigeria so I understand] Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Pedestrian signal crossings (not at intersections) An example of the typical behaviour at most UK pedestrian signals • • Clive Sawers MA MICE Ceng Traffic Engineering Consultant Becoming more sophisticated Require regular maintenance Require some enforcement Safety record improving but Injuries still severe Subject to breakdown Subject to power failure Pedestrians don’t wait Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Low-tech? • Roundabouts and physical layouts safer • • • Fewer crashes per 100 M vehs Crash severity low Pedestrians accidents rare But often not perceived to be safer Cost • • Usually a little more expensive to construct Almost maintenance free! • • Minor crash damage Feature maintenance Resurface approaches & circulatory roadway – 15 year cycle Pedestrian refuges/central medians safer than signal crossings The concept at this site was to ensure that once built there would be very little to maintain and that speeds would be constrained by the geometry and the slower vehicles. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Are signals really safe? A recent installation in my home town, Newton Abbot. It is an ugly poor slow installation at which pedestrians will not wait. I fear for the future accident record here A serious problem especially in wet weather Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Problems with power failures X A failed signal installation in Abuja controlled by a police officer. This is a common occurrence in the city. The failure was resulting in overshoots from the lower right as indicated in the next slides. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Problems with power failures Almost nothing to indicate to drivers that there is an intersection here at all! The one signal head arrowed hardly shows and the street lights (perfectly) line up straight through the intersection. I have suggested relocating two of the street lights, duplicating the signal heads and adding some road markings…one or more rumble areas as shown Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Problems with power failures Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Is this a pedestrian-friendly environment? An illustration of the roads in Bangkok where it is virtually impossible to get anywhere on foot. These footbridges are OK but not for the disabled. Not a pedestrian-friendly environment. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Basic needs for pedestrians • • ALONG - normal street Footway/Sidewalk provision Continuity Wheeled pedestrian vehicle friendly • Ample crossing points with drop-kerbs • Clear of obstructions temporary or permanent including missing links! Halkidiki, Greece Clive Sawers MA MICE Ceng Traffic Engineering Consultant I came across this appalling gap at a seaside resort in Greece. They would argue that this is not a footway/sidewalk but it was certainly used as such. Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Basic needs for pedestrians • ALONG - quiet street (<100 veh/hr) • • Safe to mix with traffic Ensure low speed Direction of traffic flow clear Lots of scope to provide sense of place A typical street in the UK where traffic volumes have been reduced such that pedestrians can more freely enjoy the space. The footways alone are much too narrow for the pedestrian volumes at peak pedestrian times. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Pedestrian Safety - Crossing • Signal junctions no guarantee of safety • Red/green man has been shown not to enhance safety • Neither do guardrails • For pedestrians to get the best and safest deal they need: • To cross a single traffic stream at a time • Speeds to be very well controlled • Not normally to have right of way • Refuges essentially safe • Refuges & speed tables even better where appropriate. A typical layout near bus stops in a UK town. Pedestrian refuges perform a safe function at thousands of such locations Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Borehamwood, Herts, UK – “before” A typical shopping street in the UK. This was changed dramatically as per the next two slides. See New Life for Main Roads website Mini-roundabouts – A Definitive Guide Clive Sawers MA MICE Ceng Traffic Engineering Consultant www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Borehamwood – “after”… Note mini-roundabout, single lane divided highway and speed table Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Borehamwood – “after”… Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Speed table using H-humps Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering H-hump SW London One of too few H-humps in the UK. These are difficult to build but potentially very effective. They are designed to allow all vehicles to cross at around the same speed by lengthening the climb for heavier vehicles that usually have much harder suspension, Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Crashes at urban/rural intersections (UK) Fatal & Serious Slight Here the roundabouts shows up as the safest intersection type in both urban and rural environment Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Some urban roundabouts A gateway roundabout in France – a good way to control speeds entering a village. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Some urban roundabouts This is a high capacity small roundabout in the UK. It is the sort of scheme that could replace many 3 -arm signal installations in Abuja and doubtless elsewhere in the country and continent. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Some urban roundabouts Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Some urban roundabouts A mini-roundabout at a crossroads; the central island is larger than the UK standard but this is often necessary to achieve the required deflection of otherwise straight paths. The complex road marking at the centre is not visible to drivers – a single uniformly painted area is preferred. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Selection of (mini-) roundabout sites • Intersections of (usually) 2 -way roads • where some turning space can be added (if needed) by: • widening corners or • narrowing approaches • • • Mostly 3 -way urban junctions Some 4 -way junctions Double and multiple 3 -way junctions Current control may be signals or priority Not normally new junctions for mini-roundabouts Side-road flow 10% of main road flow This last criterion is very important; roundabouts should not be used where the side road flows are too low… Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Site Selection factors • Getting “knotted up” at peak periods • mainly priority intersections but • can include signals (esp. when not working) • Long queues getting on (or off) • History of crashes involving: • turning • speeding • pedestrians Many 3 -arm intersections in Abuja get “knotted up” when the signals fail. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering (Motor-) Cycle Safety • Nodes (Mini-) roundabout • • Drivers MUST recognise presence of roundabout in good time Drivers’ perceive the need to yield on entry Design to incorporate speed reducing features Narrow approach lanes more (m-) cycle-friendly than one wide lane • Links (Single lane divided) • Pedal cycles mostly keep up with traffic • Special form of H-hump safe for all two-wheeled vehicles Motor-cycles feature in crashes at roundabouts – they are very vulnerable. Ensuring that entry speeds are well controlled helps to reduce the risk. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Conflicts at mini-roundabouts W It is at the crossing points (red) that most crashes occur, some may be serious. At right-angle crossroads these usually are serious highlighting the need for good deflection. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering The accident types at 3 -arm (and 4 -arm next graph) are illustrated here. It is the crossing accidents that are most influenced by correct deflection. The remainder of the accidents are associated with poor entry configuration – little or no change from the previous layout. Source: Accidents at mini-roundabouts - TRL At my sites the pattern was different, I had few pedestrian, shunt, merging and single vehicle accidents. The crossing accidents featured at those sites where I was unable for topographical reasons to ensure satisfactory deflection. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Crossing accidents dominate at crossroads; poor entry layout and lack of deflection are common at such sites. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Deal with these issues at the design stage and these installations should be reasonably safe. Source: Accidents at mini-roundabouts - TRL Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Mini-roundabouts at X-roads Method of ensuring that a crossroads mini-roundabout has sufficient “ahead” deflection – crucial. Vehicle paths must be curved to the settings shown 60 m radius or less. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Mini-roundabouts at X-roads Example of a design with a large enough centre to deflect all vehicles – similar to German compact roundabouts. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Safe scheme at a crossroads Just 1 slight injury accident in 17 years! Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Joining it all up… • Nodes • (Mini- ) roundabouts at the main intersections • Minor intersections restricted turns • Links • Add central median if sufficient width • Otherwise refuges where possible • Speed Tables at frequent intervals Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Developing your scheme P P. O. Click your way through the elements as they are added to complete the infrastructure needed to ensure as safe a community as possible; these are: Footways/sidewalks Medians Gateways Mini-roundabouts Tables Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com Rec. School February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering A common layout in Abuja Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering A common layout in Abuja Click through to show the vehicle paths and conflict area followed by pedestrian crossing lines. Note that pedestrians have to cross some 2 -way streams. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering A better layout The mini- or small roundabout as illustrated here is a powerful, cheap and very safe tool. Again, click through the vehicle and pedestrian movements as they illustrate how all the conflicts are handled and how pedestrians cross uni-directional flows, a much easier and safer task. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com Turning is easy and Uturning, needed often, is available. Pedestrians cross with little difficulty. See Mini-roundabouts – A Definitive Guide. February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Layout for divided highway intersections There are many intersections like this in Abuja so this is offered as a standard layout to permanently replace the layouts currently controlled by traffic signals, most of which were inoperative at the time of my visit. This roundabout would have: • Very high capacity • A good safety record • Pedestrian crossing points • Minimum maintenance • A central feature, maybe Cost ~ N 1 M Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Yarnton Way (SE London) • The Concept • • Reduce 2 -lane divided highway to single traffic lane retaining median Cycle lane/track added separated by hatching Roundabouts at key intersections Additional crossings where school pupils gather Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Single Lane dualling + roundabouts Note the large overrun area to ensure adequate deflection and the use of the splitter island for the cycle route. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Single Lane dualling + roundabouts Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Rural Main Roads • UK TD 9/93 Highway Link Design is 70 pages! • is available on the internet • Covers single and divided highways • For busy inter-urban routes plan for divided highways • Grade separated interchanges • Continuous central reservation • with barrier unless very wide • NO crossovers except for emergency use (must be closed) • All roadside structures to be protected with crash barriers • Provide adequate stopping facilities • Laybys every 500 m or Continuous hard shoulder • Service areas • Drain to outside unless sharp bend – slight adverse crossfall better than changes in crossfall from side to side Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Rural two-way Roads • Use well designed roundabouts for main intersections • Avoid traffic signals • Avoid crossroads & T- intersections • Along links: • • Delineate edges well Provide laybys or other areas to stop Protect necessary road-side structures Clear obvious obstructions e. g. trees, rocks to at least 5 m. On mountain routes provide edge barriers Ensure there is no confusion if parts of route divided highway. Use prohibitory double white/yellow lines to prevent overtaking at bends/summits/intersections Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Prohibitory white line system Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering This short sequence of slides illustrates the problems of appearance when lengths of divided highways are used with single two-way roads – great care must be taken not to create illusions. Divided highway or single? This road is 2 -way clearly – BUT notice the recent change in centre line markings; this is a short length between several miles of divided highway… Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering This is (obviously) a divided highway Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Note the unprotected columns (Grand Cayman) This road is 2 -way (though not obviously so) Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering This could be 2 -way or part of a divided highway - WE DON’T KNOW… Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering The opposite roadway is over here – or is it? ? ? This looks like a divided highway… Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering This is a SINGLE 2 -way road! The bridge crosses the road and a railway giving the illusion of a divided highway! Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Rural Divided Highways – Safety Risks • High speeds • Not suitable for vulnerable users – cycles, pedestrians • Not safe to cross at grade – provide bridge/underpass/roundabout • Separate roadways well or provide median barrier, prevent crossing median • Provide adequate space for running off road but protect drops • Provide underpasses for wildlife • Keep above flood plain & design for sand/debris to blow off Entering the wrong way – risk of head on collision • Use roundabouts at access slip-roads – very difficult to enter wrong way • At-grade roundabouts optional but DO NOT USE SIGNALS • Have sufficient interchanges to reduce risk of drivers reversing (having missed their exit) • Stopping • Control road-side sales on busiest main roads. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Rural divided highways near Abuja A dangerous mix of pedestrians and high speed traffic Control of roadside activities needed… Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Rural divided highways near Abuja A dangerous mix of pedestrians and high speed traffic + turning vehicles… Control of roadside crossovers needed… The problem here is that the road has been constructed without the crucial safety features built in. Relatively costly to add later compared with cost if included in the original design. But this includes overbridges etc that do not come too cheap at any stage. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering A solution to remove median crossovers Using two at-grade roundabouts not more than about 3 miles/5 km apart Allow right turns only from any side-roads Construct central median barrier Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering A solution to remove median crossovers One roundabout available to redirect left turns Partial closures of median gaps possible BUT very difficult to enforce Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering A solution to prevent crossovers Allow right turns ON Add 2 -way service link One roundabout available to redirect left turns FULL closures of median gaps possible. May help reduce pedestrian conflict with roadside sales by restricting these to side-roads. Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering A solution to prevent crossovers • Safe turning facilities Provide an over (or under) bridge for minor road • U-turning for maintenance/service/emergency Add slip roads and small roundabouts • More land take than diamond interchange Sign carefully • Longer bridge for accel. Lanes Prevent crossovers with median barrier Clive Sawers MA MICE Ceng Traffic Engineering Consultant • Sign routes carefully Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Conclusions – urban roads • The tools are available • • • (Mini-) Roundabouts Medians/refuges H-humps/tables • Highly relevant for developed countries • As Borehamwood has proved • Even more relevant for developing countries • Low maintenance costs • No signal breakdown issues • Always pedestrian friendly • Can be landscaped • So High-tech or Low-tech? Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd

International Conference on Road Safety in Africa A Low-tech Approach to Urban & Rural Safety Engineering Conclusions – rural main roads • • • Use roundabouts where possible on Single Level intersections Protect road-side objects, structures, trees, precipices Use Double White/Yellow line system on all single rural roads • Consider divided highway for busier routes • • • Reduces risk of collisions Provides safe overtaking opportunities Higher capacity & level of service Provide grade separated interchanges on major divided highways Reduce/eliminate crossovers • Avoid illusions of divided highway when actually single Thanks for listening and participating… Clive Sawers – Moor Value Ltd, UK Clive Sawers MA MICE Ceng Traffic Engineering Consultant Mini-roundabouts – A Definitive Guide www. mini-roundabout. com February 2008 Moor Value Ltd