Current trends in urban & rural road safety engineering The African Perspective

1. Current trends in urban& rural road safety engineeringThe African Perspective byClive Sawers M.A. M.I.C.E. CEng.Traffic Engineering Consultant, UK Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

2. 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 CEngMarch 2008 Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

3. Education Children road safety education Driving instruction and tests Engineering Better design – roads & layouts Better design - vehicles Safety audits Enforcement Police presence/FRSC Cameras Emergency Services Fire & Rescue Ambulance ENTHUSIASM! Road Safety Professionals Conferences & Seminars Publications Other training, liaison, forums etc… A PASSION for Road Safety The Culture of Road Safety – the 5 Es! 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. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

4. 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 Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

5. What’s wrong with signals? • Signals and pedestrian facilities are not as safe as they should be • 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 • Costs • 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] Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

6. Pedestrian signal crossings (not at intersections) • 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 An example of the typical behaviour at most UK pedestrian signals Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

7. Low-tech? • Roundabouts and physical layouts safer • Fewer crashes per 100M 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. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

8. 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 Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

9. 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. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

10. 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 Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

11. Problems with power failures Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

12. 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. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

13. 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 permanentincluding missing links! Halkidiki,Greece 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 Guidewww.mini-roundabout.com

14. 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 providesense 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. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

15. 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 Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

16. 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 Guidewww.mini-roundabout.com

17. Borehamwood – “after”… Note mini-roundabout, single lane divided highway and speed table Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

18. Borehamwood – “after”… Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

19. Speed table using H-humps Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

20. 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, Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

21. Crashes at urban/rural intersections (UK) Slight Fatal & Serious Here the roundabouts shows up as the safest intersection type in both urban and rural environment Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

22. Some urban roundabouts A gateway roundabout in France – a good way to control speeds entering a village. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

23. 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. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

24. Some urban roundabouts Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

25. 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. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

26. 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… Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

27. 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. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

28. (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. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

29. 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. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

30. 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. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

31. Deal with these issues at the design stage and these installations should be reasonably safe. Crossing accidents dominate at crossroads; poor entry layout and lack of deflection are common at such sites. Source: Accidents at mini-roundabouts - TRL Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

32. Mini-roundabouts at X-roads Method of ensuring thata crossroads mini-roundabout has sufficient “ahead” deflection – crucial. Vehicle paths must be curved to the settings shown 60m radius or less. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

33. Mini-roundabouts at X-roads Example of a design with a large enough centre to deflect all vehicles – similar to German compact roundabouts. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

34. Safe scheme at a crossroads Just 1 slight injury accident in 17 years! Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

35. 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 Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

36. Developing your scheme P Rec. 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/sidewalksMediansGatewaysMini-roundaboutsTables School Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

37. A common layout in Abuja Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

38. 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. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

39. A better layout The mini- or smallroundabout as illustrated here is apowerful, cheap and very safe tool. Turning is easy and U-turning, needed often, is available. Pedestrians cross with little difficulty. See Mini-roundabouts – A Definitive Guide. 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. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

40. Layout for divided highway intersections This roundabout would have: • Very high capacity • A good safety record • Pedestrian crossing points • Minimum maintenance • A central feature, maybe 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. Cost ~ N1M Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

41. 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 Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

42. Single Lane dualling + roundabouts Note the large overrun area to ensure adequate deflection and the use of the splitter island for the cycle route. Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

43. Single Lane dualling + roundabouts Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

44. 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 500m or Continuous hard shoulder • Service areas • Drain to outside unless sharp bend – slight adverse crossfall better than changes in crossfall from side to side Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

45. 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 5m. • 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 overtakingat bends/summits/intersections Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

46. Prohibitory white line system Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

47. 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… Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

48. This is (obviously) a divided highway Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

49. Note the unprotected columns (Grand Cayman) This road is 2-way (though not obviously so) Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com

50. This could be 2-way or part of a divided highway - WE DON’T KNOW… Mini-roundabouts – A Definitive Guidewww.mini-roundabout.com