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Introduction
5.1 In developing a cycle network it is important to ensure that the most appropriate forms of network link are put in place. Network links may be either:-
(i) Shared Road Links (Paragraphs 5.13-5.21);
(ii) Cycle Lane Links (Paragraphs 5.22-5.63);
(iii) Cycle Track Links (Paragraphs 5.64-5.78).
5.2 Provided that the hierarchy measures identified in Chapter 3 are followed then routes may be developed from any combination of the three types of network link introduced above.
Choice of Link
5.3 In order to decide which type of network link should be provided the following should be assessed:
5.4 Existing and Latent Cycle Flows: Identification of the levels of existing and latent cycle flows likely to be using a cycle route should be used as a guide as to when segregation from a road carriageway may be necessary.
5.5 Actual and latent cycle flows should be identified and assessed in accordance with the guidelines introduced in Chapter 3.
5.6 As cycle flows and traffic flows increase there may be an increased risk of cyclists being involved in accidents. Therefore where the following Annual Average Daily Cycle Flows are exceeded consideration should be given to the provision of a cycle track link:
(i) Urban Environment: Cycle Flows > 100.
(ii) Rural Environment: Cycle Flows > 200.
5.7 In some areas there may be considerable recreational cycling at weekends, but little or no flow on weekdays. In these areas average daily measurements should be calculated on the basis of flows taken over not fewer than 4 July/August weekends, to provide the average maximum recreational flow.
5.8 Motor Vehicle Flows and Speeds: Figure 5.1, developed by Sustrans from original guidelines produced by CROW, provides a graphical relationship between vehicle speeds, volume of motor vehicles and types of link provision.
Figure 5.1: Link Specification Guide Criteria
5.9 Although the CROW guidelines have been adapted by Sustrans to reflect the needs of inexperienced cyclists or family groups (who generally require segregated facilities to be considered at an earlier stage than experienced cyclists), these amendments are considered to be compatible with the Cycling by Design objective of providing a consistent standard of cycling infrastructure which may be used by the majority of cyclists.
5.10 It is thus recommended that Figure 5.1 should initially be used in conjunction with the cycle flow criteria presented in Paragraph 5.6 as the first step in choosing the most appropriate form of link provision. However, views are specifically sought on this issue.
5.11 Wide Single Carriageways: An exception to the above requirements is the treatment of Wide Single Carriageways which should be as follows:
(i) Wide Single Carriageway marked as two 5m lanes with additional 1m hard strips:
Max. 2 Way Vehicle Flows < 10,000 then provide a Shared Road Facility.
Max. 2 Way Vehicle Flows > 10,000 then provide a Segregated Cycle Facility.
(ii) Wide Single Carriageway with no hardstrips, marked as two 5m lanes:
Provide a Segregated Cycle Facility.
(iii) Wide Single Carriageway (including climbing lanes) with or without 1m hard strips marked as 2+1 lanes:
Provide a Segregated Cycle Facility.
5.12 The guide requirements specified in Figure 5.1 and Paragraph 5.6 should be complemented by a broader assessment of the following:
(i) If 85th percentile speeds are above the speed limit, consideration should be given to speed reduction measures including enforcement.
(ii) At an HGV content greater than 15% of the total flow a segregated cycle facility is recommended due to the potential increase in danger to the cyclist.
(iii) Sight distance requirements should be in accordance with Chapter 4.
(iv) With a parking pressure of greater than 85% cycle lanes are not recommended (i.e. during peak times a minimum of 85% of kerbside parking spaces are occupied, therefore the chance of an off side cycle lane being used for double parking is too great and an alternative facility should be investigated).
(v) On an urban road with junctions every 100-200m and motorised volumes in excess of 1500 veh/24-hour period a segregated facility loses its advantages as the benefit of uninterrupted cycling is nullified through cyclists having to be alert at each junction.
(vi) Standard of junction and crossing provision.
(vii) Treatment of private accesses.
(viii) Personal security. Cycle tracks remote from the carriageway may involve erosion of perceived personal security — particularly among vulnerable users.
Shared Road links
5.13 Function: Enables smooth running of all classes of traffic within the same carriageway.
5.14 Recommended Use: All types of traffic are able to mix provided that speed and volume combinations are appropriate. (Refer to Figure 5.1 and Paragraph 5.6). A shared road facility can be used in the urban or rural situation and may be provided in one of the following forms:-
(i) General Road Use;
(ii) 1m Hardstrip;
(iii) Wide Nearside Lane
5.15 Design:
(i) Use of existing road width.
(ii) Refer to individual treatments detailed in Paragraphs 5.18 to 5.21.
5.16 Advantages:
(i) No additional land acquisition required.
(ii) Cyclists retain freedom of mobility.
(iii) Safety at intersections tends to be greater than other options.
(iv) Low capital cost option.
5.17 Disadvantages:
(i) Remaining cross section may be less safe.
(ii) On street parking acts as a hindrance and may be dangerous.
(iii) Cyclists may significantly reduce overall traffic speed which may result in an increase in user stress and dangerous overtaking manoeuvres.
(iv) Generally unattractive to new cyclists.
(v) Does not necessarily channel traffic.
5.18 General Road Use: Provided the factors identified in Figure 5.1 and Paragraph 5.6 are complied with and the HGV content is less than 15%, cyclists should be able to use an existing road comfortably. This use may be enhanced through provision of 1m hardstrips or wide nearside lanes.
5.19 Use of Hardstrips: The provision of 1m hardstrips alongside new roads or by the improvement or modification of existing roads is not a design feature specifically aimed at improving conditions for cyclists. However, it is recognised that hardstrips are used by cyclists to provide a measure of separation from passing traffic. Where this is known to be the case or planned as an interim measure, road authorities must ensure that the hardstrips do not include gullies and that the level of maintenance is equivalent to that of the running carriageway.
5.20 Wide Nearside Lanes: A relatively simple and cost effective method of improving the safety aspects of a Shared Road Link is the provision of wide nearside lanes. These make use of the existing carriageway with the road markings adjusted to provide an increased nearside lane width. The use of wide nearside lanes has been endorsed by US, Australian and European authorities, and is recommended on all major routes, particularly primary distributor and district distributor roads, including single and dual carriageways. Actual cycle lanes are not marked on the carriageway.
5.21 Wide nearside lanes should be 4.25m wide to enable cyclists to have sufficient clearance from passing HGVs. Wider nearside lanes are not recommended as these may encourage other traffic to use the facility as two unmarked non-standard lanes.
Cycle Lane Links
5.22 Function: To allocate and demarcate space for cyclists within a road carriageway cross-section.
5.23 Recommended Use:
(i) Mandatory cycle lane - by cyclists only.
(ii) Advisory cycle lane - by cyclists and occasional motor vehicle and other use.
(iii) For speed and volume combinations identified in Figure 5.1
(iv) For cycle flows identified in Paragraph 5.6.
(v) To improve perceptive safety.
(vi) For coherence within the cycling network.
5.24 Design:
(i) Separation by broken (Advisory) or continuous (Mandatory) white lines and where there is parking present, preferably by a demarcation strip between the parking and cycle lane.
(ii) Refer to individual treatments detailed in Paragraphs 5.27 to 5.63.
5.25 Advantages:
(i) Cyclists are better protected and therefore feel safer than on a Shared Road Facility (but less than on a segregated one).
(ii) Motorists can safely pass cyclists.
(iii) Cyclists can avoid traffic congestion.
(iv) Cycling becomes more comfortable.
(v) Freedom of movement maintained.
(vi) More attractive to the new user.
5.26 Disadvantages:
(i) Land acquisition may be required.
(ii) Adjacent traffic speeds may increase.
(iii) Motorists may become less aware of the cyclist. Cyclists who deviate from the cycle lane may be at greater risk than those on a shared facility as the motorist may not be as alert towards cyclists.
(iv) If parking is permitted then motor vehicles will have to cross the cycle lane.
(v) Motorists may double park if the lane is advisory and may use it as an approach lane at intersections.
(vi) HGVs and buses may use the cycle lane for manoeuvres requiring extra width.
(vii) Additional maintenance may be required to avoid build-ups of debris etc.
5.27 Two types of cycle lanes are currently available:
(i) Mandatory; and
(ii) Advisory.
5.28 Mandatory Cycle Lanes:
5.29 A mandatory cycle lane is a lane into which motor vehicles may not enter. Cyclists are however permitted to enter and leave and its use is not compulsory. Because motor vehicles are prohibited mandatory cycle lanes tend to be more attractive to cyclists than advisory lanes.
5.30 Mandatory lanes are bounded by a solid white line and signs as shown in Figure 5.2. Mandatory lanes must be accompanied by a Traffic Regulation Order (TRO, refer to Appendix 1) which will be required to prohibit the use of the lane by motor vehicles (except for emergency or statutory purposes) and prohibit waiting, but may permit loading and unloading outside the working day.
5.31 If there are premises adjacent to the cycle lane which are accessible only from that lane, the Order, by prohibiting waiting and loading during the working day, may prevent access for more than 8 hours in 24 and may require the consent of Scottish Ministers.
5.32 As an alternative, cycle lanes can operate for limited time periods only, e.g. peak periods, if this eases access or parking problems. The mandatory cycle lane signs would then need to be placed in conjunction with the appropriate time plate and approval for this sought from Scottish Ministers.
Figure 5.2: Typical Layout of With-flow Mandatory Cycle Lane
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