Segregation Insert the title and of priority your at presentation junctions: a here discussion Marcus Jones, TRL Presented by Name Here Job Title - Date
Background: TfL cycle facility trials Infrastructure trialled: Segregation within the carriagewayside road crossings and separation methods Dutch style roundabout Traffic signals for cyclists- high and low level Bus stop bypasses More than 6000 participants, over 130 days of trials
Requirement for off-street trials TfL is considering proposed designs (or elements of them) not currently approved for use in UK Overseas experience not always directly transferable to UK context Need to understand how people respond under safe and controlled conditions Off-street trials establish suitability for progressing to on-street trials, and help identify issues requiring further investigation
What did we want to find out in the trials? How people use the space: their speed and position, where they stop etc- impacts on capacity Whether conflicts occur, what form they take and severity Their understanding of the facility, e.g. who has priority? Their attitudes towards it: willingness to use, willingness to cycle etc NB- changes in priority rules were not part of the trial design, so trial findings do not lead to recommendations in this area
First trial: Segregation within the carriageway How far should segregation end before side roads? LTN2/08: As a result of concerns over the safety of parallel cycle tracks crossing side roads, it is becoming common European practice to reintroduce cyclists to the main road in advance of a junction. Cyclists pass the junction on the carriageway and then re-join the cycle track. The merge onto the carriageway should be at least 30 metres from the junction to reduce the risk of conflict with left turning traffic.
Two distinct approaches to this situation Re-introduce to the traffic before the junction (LTN2/08); or Segregate to the junction and give cyclists priority over turning vehicles Geometry, including raised crossings, can be used to manage vehicle speeds and position, particularly in the latter case
Examples Reintroduction Segregation to the turning Page 7
Trial layouts Test track Driving simulator
Set-back Distance
Reintroduction (>20m) Two distinct conflict points Cyclists and drivers have space to adjust to each other Preferred by nearly half of participants More familiar situation to UK road users?
Segregate to junction (<5m) Single point of conflict Reduced vehicle speeds, perpendicular approach Greater passing distance Preferred by slightly fewer participants Who has priority at junction?
Mid-way (~>5m to <20m) Two adjacent conflict points No effect on vehicle speed or position Limited space to merge into traffic flow Worst of both worlds, don t do it!
Light separation methods Wands Low profile Zebras
Light segregation Compared solid kerbs, wands, zebra separators against white line baseline Measured and position and speed in lane Qualitative survey of safety and comfort All three were quite similar in performance, slight preferences for kerbs, then wands, then zebras. Not focus of trial, but some concerns raised by participants about who has priority at exits to separated sections
Dutch Style Roundabout Orbital cycle track with priority for cyclists at entries and exits As built on TRL test track (Dutch-style markings)
Common issue: who has priority? When turning across a cycle lane to turn left? At exit to separated lanes? When turning in or out of a roundabout? In The Netherlands and Denmark, cyclists using adjacent cycle tracks will often have priority over turning vehicles; everyone understands this to be the case and expects it However, in trials, most people were prepared to give way anyway. Encouraged by the infrastructure?
The Highway Code 206 Drive carefully and slowly when: needing to cross a pavement or cycle track; for example, to reach or leave a driveway. Give way to pedestrians and cyclists on the pavement reversing into a side road; look all around the vehicle and give way to any pedestrians who may be crossing the road turning at road junctions; give way to pedestrians who are already crossing the road into which you are turning Does standard (e.g. DMRB) highway design undermine the priority rules?
Discussion In principle, is giving cyclists priority over turning traffic the right approach when designing segregated facilities? Does this need to be supported by regulatory change? Do drivers respect priority rules if infrastructure sends a contradictory message? Is appropriate design of infrastructure sufficient to encourage the desired behaviour, without requiring any regulatory change?
Marcus Jones TRL Ltd mjones@trl.co.uk 01344 770552