New Forest NCN Audit

Sustrans want to see a UK-wide network of traffic-free paths for everyone walking, wheeling or cycling, that connect cities, towns and countryside. Comfort & accessibility are fundamental to inclusive design for all and it is recommended to provide good quality, well-maintained smooth surfacing (in line with LTN 1/20 (1.1)).

Poor quality surfacing inhibits users, and here are some examples of how:

• Disabled cyclists, and land cycles such as handcycles, struggle due to rough surfacing such as potholes or rumblestrips, as they go that way to the part or side of the road
• Those with more than two wheels will be less able to traverse around imperfections in the surfacing (Wheels for Wellbeing) and are adversely affected by steep cambers which can prevent people from being able to turn a path or at all possible
• Blind and partially sighted people are also impacted by imperfections of a surface (LTN 1/20)
• Extremely uneven surfaces can become a slip hazard in frosty or beyond and require appropriate gritting

Wheels for Wellbeing state that surfaces should be free of potholes or other hazards and regularly cleared of leaves, mud and debris which can be hazards or create slip hazards.

Terminology

1. Sealed or unsealed: this refers to the infiltration of water through a surface. A sealed surface will allow water through it, an unsealed surface will allow water to drain through the surface
2. Bound or unbound: this refers to whether the surface is loose material held together or sealed as a homogeneous mass. Surfaces that do not deaggregate are bound

Introduction

Key to considering and maintaining a path with a good quality, ideal & safe for all is understanding:

1. The durability of the surface type and subsequent construction maintenance requirements
2. Drainage & subsequent surface requirements

Durability & maintenance

Surfacing types differ in durability and the choice of surface will therefore have an impact on any maintenance requirements. The most durable surfaces are bound surfaces, and therefore require the least maintenance. The least durable surfaces are unbound surfaces, and will require the most maintenance.

Appropriate maintenance may be ensuring good quality and, in service LTN 1/20 Summary Principal 14 (section 1.1) states that surface materials should be easy to maintain, but that exceptions will be allowed for streets of special heritage value. LTN 1/20 Summary Principal 13 (section 1.1) recommends that all route proposals should have a clear maintenance regime allocated.

Drainage & camber

Sustrans’ best practice to ensure that all routes are free draining is to design in a way that avoids ponding. In flatter contexts, a free draining surface can be achieved through either a permeable (unsealed) material or an appropriate camber to allow the water to run off the surface. LTN 1/20 clause 5.10 states that camber gradient should “not exceed 2.5%” and 5.24 states that “for cross-fall shared use no more than 2% is required” for drainage purposes, as steep cambers can cause instability to cycles with more than two wheels.

LTN 1/20 clause 7.5.5 suggests speed cushions should have a sinusoidal profile at least 1:14 (slope), that speed bumps should not be necessary if guidance on reducing traffic volumes has been properly followed.

Types of surfaces

Unbound surfaces

While dirt or granite dust surfaces form a smooth and durable surface. These surfaces are highly dependent on high quality construction techniques and long-term maintenance plans. Unbound surfaces have a typical lifespan of 5-10 years.

Unbound surfaces are susceptible to damage from standing water, and for suitability for all, comfort be considered to avoid this. The ‘Paths for All’ Surfacing Guide for Paths Projects states that higher maintenance is required for unbound surfaces, particularly woodland settings, where the path is more susceptible to wash out.

For steep surfaces (with gradients over 1:10), semi-bound to bound surfaces are recommended to ensure durability.

Semi-bound surfaces

Self-binding surfaces are an example of a semi-bound surface. They are chosen in some circumstances away from the highway, where recycled tarmac/old asphalt (tarmacings) cannot be applied. They can be highly durable. Examples include Ultitrec, which is available in black or red and CDEEC which is available in red, grey, green, bronze or red.

The “Paths for All” specification states that semi-bound surfaces are better suited to heavy trafficked routes than unbound, as well as routes with steep sections, routes in wooded locations and general all weather use routes. They have a typical lifespan of 10-15 years.

Unbound surface

Semi-bound surface

Bound surfaces

Bound surfaces typically use a resin-based binder to glue aggregate together. Tarmac can provide very smooth and durable finishes which can last more than 30 years before significant maintenance is required (Paths for All). However, when first laid, it can also create increased maintenance requirements. Leaf litter can also quickly create very slippery conditions.

While there may be initial concerns about disturbance to the natural environment or the appearance of sealed surfaces, these can be addressed through choice of materials (LTN 1/20 16.2.13). Resin-bound aggregate can be obtained in different colours, reducing the visual impact of this type of surfacing as can the “tar spray and chip” on old tarmac. “Tar spray and chip” can be sprayed onto an unbound or semi-bound surface. This low-cost surface repair can be particularly useful in short sections to add durability at location, however, tar spray and chip has a lifespan closer to that of semi-bound surfaces (10-15 years).

Smart Surface also offers a solution to revitalise worn-out paths and provides a better landscape fit in rural paths where bitumen based surfacing products are not suitable or desirable.

Bituminous surfacing / Tarmac / Asphalt concrete

Resin-bounded nibbar surfacing

Coloured bituminous surfacing

Tar spray and chip

Costs

The overall costs of unbound, semi-bound and bound surfaces vary dependent on the different surface options, location of the project, availability of skilled contractors (required for some surfaces), durability requirements and maintenance requirements. Therefore it is recommended that further analysis is undertaken, specific to any project to ensure the best value for money whilst also ensuring the design is accessible and inclusive for all.

Conclusion

Route 2 contains sections of varying terrain, historic requirements and varying habitat. To bring the route to LTN 1/20 standards, different surface types would be appropriate for different sections of the route.

LTN 1/20 recommends that wherever possible, bound surfaces should be used to ensure accessibility and reduce maintenance requirements. However, in some locations along route 2 semi-bound or unbound surfaces may be more appropriate, as long as appropriate maintenance regimes are put in place.

Semi-bound surfaces are recommended as a minimum in areas requiring surfacing, as this type can be maintained but will be historic design features along the path must also be maintained.

Appropriate stakeholder engagement is also recommended to ensure any design suits the needs of all potential users, as well as other stakeholders.

What are Quietways?

Quietways are either:

• Rural lanes, where motor traffic speeds and volumes are sufficiently low for people walking, wheeling, riding and horse riding, to comfortably share with motorised traffic. These can be formally designated as Quiet Lanes
• Streets in built up areas where volumes and speeds of motor vehicles are low enough for people cycling to comfortably share the carriageway with motor traffic. In this situation people walking and wheeling will often be accommodated by one or more footways

What are the key design principles?

Key design principles are summarised below:

• In built-up areas, where people are expected to cycle on the carriageway, motor vehicle volumes should be below 2,000 Average per day (people per day). The speed limit should be 20mph, and people in motor vehicles should generally be driving at or below the speed limit. Where no footway is provided, the motor vehicle volumes and speeds may need to be significantly lower than this. In addition, peak flows should not be more than 10% of the 24-hour flow.
• In rural settings achieving speeds of 20mph may be difficult, and a shared use path options (and a speed limit) of up to 30mph will generally be acceptable with motor vehicle flows of up to 1,000 PCU per day. Again, peak flows should not be more than 10% of the 24-hour flow.
• People walking, wheeling, cycling and where appropriate horse riding should feel safe and comfortable to use the route, and all users should be aware of who they are sharing the surface of the lane or street with, with signage and markings used where appropriate.

How can existing streets, lanes and roads be made into Quietways?

Where existing volumes or speeds of motor vehicles are currently higher than this, these can be reduced through a variety of measures. These should be appropriate for the specific location, and can include:

• Lowering speed limits
• Quiet lanes designation and signage (for rural lanes)
• Modal filters to prevent some or all private motor traffic passing along a street or lane
• Centre line removal and/or reducing carriageway width
• Surface changes and treatments
• Physical traffic calming features, such as speed cushions and build-outs
• Junction priority changes
• Changes in signage, including adding gateway features

It is important that local communities are engaged in the process to achieve social support and make sure the solution meets the needs of all users. This is especially the case for some aspects such as Quiet Lanes designation and modal filters.

What are the advantages of Quietways over Traffic-Free provision?

Quietways are a key solution to connect people for a number of reasons:

• In many places, there is not enough space to build cycle tracks and other infrastructure next to roads
• Traffic-free provision such as cycle tracks or shared use paths, is often significantly more costly to implement. It also typically results in significantly more carbon emissions and environmental impacts from construction.
• Creating Quietways can help to create healthier streets. Where volumes and speeds of motor vehicles are low, it is typically a space that is desirable for people to spend time in, as well as travel through.
• A Quietway is more likely to be overlooked and have natural surveillance than an isolated greenway, and therefore some people may feel safer (especially at night) to use one.
• In particular, Quiet Lanes can help to stabilise or use modal shift, though making people feel safe when using what are often already lightly trafficked lanes for walking and cycling. Within towns and cities, Quietways can also form a key element of the network, including by connecting people to and from the core routes in a local cycling network.

Where can I find out more?

Key sources of design guidance are listed below:

• Local Transport Note (LTN) 1/20 - Cycle Infrastructure Design
• Manual for Streets and Manual for Streets 2
• DfT Designing for Walking
• Traffic Signs Manual
• Inclusive Mobility
• Active Travel England Design Assistance and Scheme Review Tools
• Local Transport Note (LTN) 1/07 - Traffic Calming
• Traffic Advisory leaflet 3/04 - Quiet Lanes