July Guidance. Traffic calming for bus routes

Transcription

1 July 2009 Guidance Traffic calming for bus routes

2 3 Foreword Supporting comments Around 85% of all public transport journeys in Greater Manchester are by bus, making this the most important mode of public transport for Greater Manchester residents and visitors. Greater Manchester Passenger Transport Executive (GMPTE) is committed to providing bus services that can offer a real alternative to car use. Alongside its drive to improve bus services, GMPTE recognises the need to improve road safety, in line with the government s casualty reduction targets and Greater Manchester Local Transport Plan (GMLTP) aims. Well-designed traffic calming measures on bus routes can improve the street environment and reduce accidents, while having minimal impact on bus passengers and services. GMPTE and the ten Greater Manchester local authorities continue to work in partnership with bus operators to improve bus services and these guidelines show how public transport and road safety can complement each other. The Greater Manchester Association of District Engineers (GMADE) has endorsed these guidelines, recognising that Greater Manchester s streets can be made safer without unduly affecting public transport. In general buses are a safe form of transport, both for passengers and for other road users. While traffic calming is usually targeted at reducing car speeds, bus operators recognise the need for these measures as part of an overall road safety management strategy. The Greater Manchester Bus Operators Association (GMBOA) fully supports the recommendations in this guidance document, as representing current best practice for traffic calming on bus routes, without undue adverse impacts on bus service reliability, or on the comfort of our passengers and drivers. Chair of Greater Manchester Bus Operators Association (GMBOA) It is imperative that councils and partners across Greater Manchester work together in a collaborative way, if we are to deliver a 21st century public transport system. In doing so, a balance needs to be achieved which will assist bus services and also ensure that the highway remains safe for communities. These guidelines will assist those responsible for designing highway measures and ensure that our streets are made safer. I am pleased to endorse these guidelines. Chair of Greater Manchester Association of District Engineers (GMADE) Michael Renshaw, Interim Bus and Rail Director, GMPTE

3 4 5 Contents Introduction Page 5 Introduction 6 Bus-related considerations 7 Road classifications 8 Traffic calming techniques 14 Installing new traffic calming schemes 15 Bibliography 16 Appendix i: Summary of guidelines 18 Appendix ii: Key vehicle dimensions Road safety improvements, including the implementation of traffic calming measures, are aimed at meeting government casualty reduction targets and achieving the objectives of Greater Manchester s Local Transport Plan (GMLTP). Well-designed traffic calming measures on bus routes can improve the street environment and reduce road accidents while having minimal impact on bus operations. Since GMPTE published its original guidance on traffic calming for bus routes, there have been significant developments, both in terms of potential measures and types of vehicles. Consequently, this updated technical advice has been produced. This guide has been produced to promote consistency in approach across Greater Manchester and to provide a reference for highway authorities both within the GMPTE area and outside, on best practice for implementing traffic calming which achieves safety aims without compromising the comfort, safety and convenience of bus passengers. It is possible that some existing traffic calming schemes do not comply with these latest guidelines and are therefore unsuitable for bus operation. We would encourage highway authorities to consider amending those existing schemes in accordance with these new guidelines. This is particularly relevant to routes operated by low-floor or articulated buses. Key points On bus routes, it is preferable to have traffic calming schemes which do not include vertical deflection measures. The measures used should be suitable for the types of buses that use the route. The use of horizontal deflection is generally acceptable, except on routes where articulated buses operate. Speed cushions are the preferred vertical measure on bus routes. These are best used in small numbers, as part of a combined scheme of traffic calming measures. Speed tables and raised junctions are acceptable in small numbers at key locations, preferably as part of a combined scheme of traffic calming measures. Special care should be taken to relocate parking far enough away from traffic calming measures to avoid hindering bus operation. Round topped road humps are not acceptable on bus routes. The cumulative effect of all traffic calming measures, such as increased discomfort to drivers and passengers as well as the premature failure of bus components, should be carefully considered. A summary of the acceptability of traffic calming measures on bus routes is shown in Appendix i.

4 6 7 Bus-related considerations Road classifications This document provides general advice and geometric specifications which should be adhered to when designing traffic calming on bus routes. However, more importantly, it is intended to raise awareness amongst designers of the needs of buses, so that bus facilities and operators are considered as an integral part of the design process. Those designing and implementing traffic calming schemes should take the following into account: Buses have firmer suspension systems than cars, similar to most other large vehicles carrying heavy loads. Buses are less manoeuvrable than cars. Bus operators have a duty of care to their passengers, particularly the elderly and disabled, some of whom may be standing or moving along the bus. Bus operators must have due regard for the health and safety of their drivers. In some situations traffic calming can cause great discomfort, especially if the bus route involves passing over numerous vertical deflections. Excessively harsh traffic calming can lead to increased wear and tear to buses and can, over a prolonged period, lead to damage and increased maintenance costs. Bus services operate to a timetable. Reliability is a key factor if customer confidence is to be maintained. Traffic calming schemes should avoid increasing bus journey times by service diversions or by slowing buses down significantly more than other vehicles. The design of traffic calming schemes will vary according to the type of road and the activities that take place along it. The Department for Transport s (DfT) Traffic Advisory Leaflets (TALs) give advice on the use and effectiveness of various traffic calming measures in a number of situations. These leaflets are referred to as appropriate, and further details are provided in the Bibliography to this document on page 15. The Institution of Highways & Transportation (IHT) publication on traffic calming techniques provides useful details of individual measures and schemes introduced and their likely impact on traffic speeds and accidents. Local roads in residential areas A speed of 20mph is becoming the general target for local roads in residential areas. This can be achieved by incorporating selfenforcing traffic calming measures into a designated 20mph zone. Alternatively, 20mph speed limit signs and roundels can be used providing vehicle speeds are already at the appropriate level (see Traffic Advisory Leaflet 9/99 for more details). Generally, buses operating through such areas will be local services and should be able to travel at 15 to 20mph without undue difficulty. It is advisable for bus operators to consider an operational speed of 15mph or less when crossing traffic calming features like speed tables, to minimise discomfort (see Traffic Advisory Leaflet 10/00). Distributor roads On 30mph distributor roads, traffic calming aims to keep prevailing vehicle speeds to within the speed limit and to treat specific accident sites or lengths of road. Designers should give due consideration to the potential for using horizontal deflection measures where appropriate to alleviate some of the difficulties reported by bus operators where excessive numbers of road humps and cushions have been installed along high-frequency routes.

5 8 9 Traffic calming techniques This section outlines a toolkit of typical measures available to designers of traffic calming schemes with due consideration to the passage of buses and the comfort and convenience of passengers. It should be noted that there is a growing trend among highway authorities towards adopting a policy of having no vertical deflection in traffic calming schemes. GMPTE welcome this development and would encourage all highway authorities to fully consider this approach. A. Visual appearance Changing the road s appearance provides a way of altering a driver s behaviour. Drivers can be encouraged to slow down through the use of road markings such as central hatching along wide sections of carriageway. Road markings can also be used to create an impression of a narrowing in the carriageway. Coloured or textured road surfacing and physical measures such as bollards, islands or planting can change the character of the road. This can offer an improved highway environment for both road users and residents. Special consideration should be given to the needs of cyclists. Roads in new developments should be designed to incorporate this approach. C. Access control measures The use of residential areas by through traffic can have a detrimental impact on the local environment. Measures such as local closures or one way systems can be used effectively to deter through traffic, although consideration should be given to local access needs. Bus services can be catered for in such schemes by installing bus gates or lanes, which can now be enforced by local authorities via fixed or mobile cameras. This should improve observance and compliance of the restrictions. Physical barriers, including rising bollards or moving arms, are not recommended due to reliability issues, vandalism and the possibility of being struck by other vehicles. D. Priority changes Altered priority at junctions can be used to favour bus routes. However, a junction s capacity could be affected (DfT Traffic Advisory Leaflet 6/01) and therefore care should be exercised to ensure that buses will not be delayed as a result of any changes. Mini-roundabouts can slow traffic on all approaches provided there are balanced flows on all arms. On bus routes, painted mini-roundabouts are often considered preferable to those with raised central domes which buses then have to negotiate. Special consideration may need to be given if articulated buses have to turn at a raised mini-roundabout to minimise passenger discomfort. B. Speed cameras and Vehicle Activated Signs Cameras and other technology can provide viable alternatives to hard engineering methods. Vehicle Activated Signs (VAS) that warn drivers about their speed or hazards ahead have also been effective at specific locations (see DfT Traffic Advisory Leaflet 1/03). However, excessive proliferation of these signs could lessen their impact and should be sited appropriately. Making changes to traffic signal timings or staging is another way of discouraging through traffic. Measures such as bus lanes along junction approaches should be considered where appropriate (see DfT Traffic Advisory Leaflets ITS 5/03 and ITS 6/03). Selective Vehicle Detection (SVD) will also provide additional benefit for buses.

6 10 11 Traffic calming techniques continued E. Horizontal deflection devices To minimise passenger discomfort on bus routes, horizontal deflection (see DfT Traffic Advisory Leaflets 9/94 and 12/97) is generally preferred over vertical deflection. However, it is recognised that horizontal measures alone may not always be sufficient to reduce speeds to the required level. Horizontal traffic calming measures can be incorporated into hard-landscaping projects to enhance the visual appearance of a scheme. Chicanes, which allow two-way flow with reduced carriageway width are a common form of horizontal deflection although care needs to be taken to ensure that parked vehicles do not impede buses. Trials have shown that chicanes designed to allow the passage of an articulated bus have little effect on the speed of most other vehicles. Therefore, chicanes are not recommended on articulated bus routes. Large central islands can be used to create narrower carriageways (see Traffic Advisory Leaflet 7/95) and road markings such as crosshatching and cycle lanes can be used to create a visual, but not physical, narrowing of the carriageway. Overrun areas can also be used to reinforce the appearance of horizontal deflections. These areas are designed to help large vehicles such as buses negotiate narrowings, chicanes, roundabouts and tight corners, particularly on narrow residential roads (see Traffic Advisory Leaflet 12/93). Pinch-points can calm traffic speeds by requiring vehicles in a particular direction of travel to give way to another. At such features, consideration should be given to the safety of cyclists such as provision of a cycle by-pass. Care should be taken to ensure that bus stops are sited far enough away from pinch-points to prevent their obstruction. Also, these priority working chicanes should only be used on lightly trafficked bus routes, where giveway restrictions do not unduly affect journey times. All of the measures discussed here can successfully reduce vehicle speeds. They are generally acceptable on bus routes, although special care needs to be taken to ensure that adjacent parking does not impede buses and bus stops, and that the geometry of measures is sufficient to allow the passage of longer buses. F. Vertical deflection devices The requirements for road humps are given in the The Highways (Road Humps) Regulations On bus routes, vertical deflection should only be considered where road safety cannot be enhanced satisfactorily by other measures discussed in these guidelines. Vertical deflections can also delay emergency service vehicles particularly ambulances and fire appliances (see Traffic Advisory Leaflet 3/94). Speed cushions If vertical deflection is necessary along a bus route, speed cushions are the preferred measure as they generally have less impact on buses than speed tables whilst still reducing vehicle speeds. Care must be taken to ensure that cushions are designed with an understanding of bus axle widths, so that a bus can straddle the cushion comfortably, particularly when there are adjacent parked vehicles. Cushion locations can be protected by the implementation of either waiting restrictions or a build-out of the footway to ensure that the feature is self-enforcing. It is very important that there are no parked cars in the running lane, in close proximity of the cushion to allow correct alignment of a vehicle on approach. This is essential in preventing the bus having to go two wheels up over cushions, which can be uncomfortable for passengers. Traffic Advisory Leaflets 4/94 and 1/98 recommend that the side slopes of speed cushions should not be greater than 1 in 4. This is generally acceptable to GMPTE and bus operators, although double rear wheels do run over the edges. More rounded profiles can be used to reduce this effect on buses. On all bus routes cushions should be a maximum of 1700mm wide (including side slopes), 75mm high and have on/off gradients of 1 in 8, but preferably shallower. The suggested spacing between consecutive cushions should be approximately 80m. The needs of cyclists should be considered and ideally 1.0m should be left between the edge of the cushion and the kerb. Where this is not possible, the gap may be reduced to 0.75m. In exceptional cases, where there are additional hazards to cyclists, such as a gully, this gap may be extended up to 1.5m. Speed cushions should not be sited either at or on the immediate approach to or exit from a bus stop.

7 12 13 Traffic calming techniques continued Two abreast cushions Layouts both with and without central refuges are acceptable if there is adequate control over parking. Buses negotiating cushions can be hindered by vehicles parked too close to the features. In the case of articulated bus routes, parked vehicles in the running lane should be at least 25 metres from the cushions. Two abreast cushions with build-outs This is a layout that is suitable at many locations and on bus routes. It is preferred to three abreast cushions although the kerb extensions may be replaced with cushions, producing three or four abreast layouts. If parking is continuous throughout the day, the kerb extensions could be omitted but it is important to ensure that vehicles cannot drive through vacant parking spaces to avoid traversing the speed cushions. Three abreast cushions On many roads this layout is the simplest and cheapest to install. However, even with parking controls along both sides of the road, buses frequently have to be driven over the central cushions. This is only acceptable where traffic flows are fairly low in both directions. Flat topped humps (speed tables) These features have a long plateau and lead-in ramps. They are designed to reduce discomfort to longer wheelbase vehicles, though they do require buses to slow down more than cars. Particular problems can occur as the rear wheels of a bus leave the exit ramp at speed tables, where the impact and suspension movement is greatest. Speed tables should generally only be used on bus routes at key locations, such as schools or shopping centres. Closely spaced speed tables should be avoided on bus routes. GMPTE and bus operators would prefer no more than five speed tables on any bus route. Heights of up to 75mm are acceptable, with recommended entry and exit ramp gradients of no steeper than 1 in 15. The plateau should be a minimum of 6 metres long (12.5m on articulated bus routes). In bus-only streets where it is sometimes desirable to use speed tables to delineate pedestrian crossing points and to moderate vehicle speeds, ramp gradients of between 1 in 20 and 1 in 30 are preferred. In one-way streets, the exit ramps may be made less severe than the approach ramps to assist buses leaving the speed table. When speed tables are constructed on roads with steep inclines, care should be taken with the design of the ramp gradients to avoid vehicles grounding (see Traffic Advisory Leaflet 2/96). The use of sinusoidal or S profile ramps is not considered acceptable on bus routes. Raised junctions Raised junctions are similar to speed tables but cover an entire junction, with ramps on all approaches. They are usually flush with the footway providing a safer crossing point for pedestrians. Design considerations for speed tables on bus routes also apply to raised junctions. Rumble strips Rumble devices, including areas of coarse textured road surface, are generally acceptable at normal bus operating speeds. However, they can create unacceptable noise for adjacent residents particularly if there are a lot of strips and there is a relatively high volume of traffic. Designers should be mindful that resonance can occur at slower speeds which may encourage drivers to increase their speed in order to reduce the vibration in the vehicle (see Traffic Advisory Leaflet 11/93). Round topped humps These are not considered acceptable on bus routes in Greater Manchester as these features create a double vertical deflection which can be very uncomfortable for bus occupants and can damage bus suspension over a prolonged period.

8 14 15 Installing new traffic calming schemes Bibliography Consultation and partnership working Traffic calming proposals affecting bus routes, access to bus garages and diversionary routes should be discussed with GMPTE and bus operators early during scheme development so that issues can be resolved and suitable designs agreed. GMPTE requests that highway authorities, through the design process, consider these guidelines and engage with our Traffic Manager to ensure that road safety is enhanced without compromising bus services and the comfort and convenience of passengers. Consultation information should cover the background to the scheme. GMPTE encourages the use of innovative designs to achieve the required level of traffic calming without adversely affecting bus operations. Preliminary discussions at the design stage will be followed by more formal consultation through traffic management liaison and legal advertisement as necessary. In some cases there can be a significant delay between the initial consultation and implementation stages. In these situations it is important to liaise closely with GMPTE to ensure that any changes, such as the introduction of articulated buses, are taken into account before the scheme is implemented. Installation and maintenance All traffic calming should be carefully designed and installed to prevent problems with parking, access and grounding. Special care is needed at bus stops to ensure that access and egress is not compromised, and to reduce the risks to passengers who have just boarded or who are waiting to alight. The quality of the construction and subsequent maintenance should be to a high standard ensuring the continued effectiveness of the measures throughout their life. Where significant maintenance operations are being considered on older traffic calming schemes, consideration should be given to upgrading features to current standards. Traffic Advisory Leaflets: available at 3/93 Traffic calming special authorisations 11/93 Rumble devices 12/93 Overrun areas 13/93 Gateways 2/94 Entry treatments 3/94 Fire and ambulance services Traffic calming: A code of practice 4/94 Speed cushions (see TAL 1/98) 7/94 Thumps thermoplastic road humps 9/94 Horizontal deflections (see TAL 12/97) 7/95 Traffic islands for speed control 2/96 75mm high road humps 6/96 Traffic calming traffic and vehicle noise 8/96 Road humps and ground-borne vibrations 4/97 Rising bollards 12/97 Chicane schemes (see TAL 9/94) 1/98 Speed cushion schemes (see TAL 4/94) 2/99 Leigh Park area safety scheme, Havant, Hampshire 9/99 20mph speed limits and zones 8/00 Bus priority in SCOOT 1/00 Traffic calming on major roads 10/00 Road humps: discomfort, noise and ground-borne vibration 12/00 Urban street activity in 20mph zones Ayres Road Area, Old Trafford 3/01 Urban street activity in 20mph zones Seedley, Salford 6/01 Bus priority 1/03 Vehicle activated signs 1/05 Rumblewave surfacing 2/05 Traffic calming bibliography 1/07 Emergency services traffic calmimg schemes: A code of practice ITS 5/03 Public transport priority ITS 6/03 Access control Statutory Instrument 1999 No.1025 Highways (Road Humps) Regulations 1999 available at Local Transport Note available at 1/07 Traffic calming Health and Safety Guidance available at London Cycle Design Standards Transport for London, May 2005 available at Traffic Calming Techniques The Institution of Highways and Transportation, January 2005 Traffic Calming Measures for Bus Routes Transport for London, September 2005

9 16 17 Appendix i: Summary of guidelines CALMING MEASURE BUS OPERATIONAL VIEW ADDITIONAL INFORMATION Appearance/perception Coloured surfacing Supported Texture change Supported Consider noise intrusion Carriageway narrowing Generally supported Spacing should take account of parking/streetscene activity Should not unnecessarily delay buses Bollards, trees, planters, traffic islands, pedestrian refuges Generally appropriate, particularly where pedestrian accessibility can be improved Road markings Supported Speed activated devices Safety cameras Supported Physical barriers and Traffic Regulation Orders (TROs) Vehicle Activated Signs (VAS) Supported Spacing should take account of parking/streetscene Should not unnecessarily delay buses Bus gates Supported Can be enforced by camera Automatic bollards Not recommended, where used, access should be maintained without time penalty Can create problems due to reliability issues, vandalism and possibility of being struck by vehicles Changes in priority Altered priority Generally supported Buses should be given priority where possible Horizontal deflections Mini-roundabout Generally supported Painted central island preferable to raised area Kerb extensions (build outs) Central islands, chicanes Pinch points Supported, particularly at bus stops Central islands generally supported and specific use of chicanes supported Generally supported on routes with low traffic flows and where queues are not likely to develop Vertical deflections Speed cushions Acceptable where vertical measures are necessary Parking at cushions must be prevented by enforced TRO or physical measures allowing buses to straddle the cushions Flat topped humps (speed tables) Supported, where other measures are inappropraite Should allow space for buses to pass Must take account of approach/exit of bus stops Rumble strips Generally supported Consider noise intrusion Round topped humps Not acceptable on bus routes Numbers and spacing should not introduce delays for buses Design should take account of parking which may obstruct buses Numbers and spacing should not introduce delays for buses Design should take account of parking which may obstruct buses Maximum height 75mm Maximum width 1.7m On/off ramp gradient no steeper than 1:8 Side slope ramps no steeper than 1:4 Preferred spacing of sets 80m Cumulative effect must be taken into account. More than one scheme per route unusual Should be cited away from bus stops Maximum height 75mm Ramp gradient no steeper than 1:15 Flat top minimum 6m (12.5m for articulated buses) Cumulative effect must be taken into account. More than one scheme per route unusual

10 18 Appendix ii: Key vehicle dimensions A variety of bus types operate within Greater Manchester. The table below provides an overview of typical bus dimensions. The dimensions provided are intended as a guide only. If the specific dimensions of a bus used on a route are required, designers should contact GMPTE early in the design process. Type Length Width Track Width Kerb to Kerb Turning Radius Midi Bus 10m 2.3m 2m 8.3m Single Deck Bus 12m 2.4m 2.3m 10.4m Double Deck Bus 9.5m 2.5m 2.3m 9.7m Articulated Bus 17.9m 2.5m 2.5m 11.5m Partners

11 For more information on traffic calming for bus routes in Greater Manchester, please contact: GMPTE Traffic Manager: GMPTE Customer Relations Team: