Hold the Left Junctions (Cycle Segregated Junctions)
The principal aim of this design is to eliminate the left hook risk to cyclists while leaving motor traffic capacity unaffected. A small number of junctions have now been constructed in London and look to be working well. We would like more junctions altered to this design. For example there are currently (Nov 2017) plans to "improve" the notorious Borough junction. However the new design still has the 2 massive left hooks that are responsible for several collisions each year. These could be eliminated by adopting a Hold-the-Left design.
Information about this junction design is not easy to find, so I have brought some of it together here.
Articles on the London Cycling Campaign Web site
https://lcc.org.uk/articles/tfl-launches-new-hold-the-left-junction-on-cycle-superhighway-2
https://lcc.org.uk/articles/campaign-cycle-segregated-junction-explained
Camden Cyclists presentation by Jean Dollimore
http://camdencyclists.org.uk/wp-content/uploads/2015/03/Eliminating-left-hooks-for-LTLG.pdf
Transport for London Video about their first HtL junction
https://www.youtube.com/watch?v=JFL-c7Sv9Q8
Alternative design developed by Rik Andrew that works with only 2 general traffic lanes. Click on link below.
Information about this junction design is not easy to find, so I have brought some of it together here.
Articles on the London Cycling Campaign Web site
https://lcc.org.uk/articles/tfl-launches-new-hold-the-left-junction-on-cycle-superhighway-2
https://lcc.org.uk/articles/campaign-cycle-segregated-junction-explained
Camden Cyclists presentation by Jean Dollimore
http://camdencyclists.org.uk/wp-content/uploads/2015/03/Eliminating-left-hooks-for-LTLG.pdf
Transport for London Video about their first HtL junction
https://www.youtube.com/watch?v=JFL-c7Sv9Q8
Alternative design developed by Rik Andrew that works with only 2 general traffic lanes. Click on link below.
elh_design_for_2_lane_jcts.ppt | |
File Size: | 430 kb |
File Type: | ppt |
Existing HtL junctions
Road Names Postcode Lat/Long
Kennington Road/Kennington Park Rd (A3) SE11 4PZ 51.4843/-0.1102
See post at https://southwarkcyclists.org.uk/a-hold-the-left-junction-finally-built/ for details
Whitechapel Rd (A11)/Vallance Rd (B108) E1 7QA 51.5184/-0.0629
Mile End Rd (A11)/Grove Rd, Burdett Rd (A1205) E3 4PL 51.5250/-0.0348
Clapham Rd (A3)/South Lambeth Rd (A203) SW8 1UG 51.4731/-0.1217
Clapham Rd (A3)/Stockwell Rd (A203) SW8 1UG 51.4724/-0.1222
Note the two A11 junctions on CS2 are only partial implementations on the E-W arms. The Stockwell versions have Hold-the-Left on only 1 arm of the junction. These partial implementations do not get the full benefit of Hold-the-Left, but they do show that drivers and cyclists can easily navigate this type of junction.
Minimum width needed
A common claim is that there is not enough room for the extra cycle lane plus the island needed between traffic lanes. These add 1.5-2m (cycle lane) and 1.2-1.5m (island), so a total of 2.7 to 3.5m.
Because pedestrians can cross in one phase it is possible to remove, or very much narrow, any central island. This will save in the region of 2m. In addition, at any junction where HGVs are less than 10% of traffic it is possible to reduce traffic lanes to 2.5m from the usual 3m. On a 3 lane road this provides 1.5m to play with. From this arithmetic it can be seen that at a conventional signalised junction with 2 stage crossings it will always be possible to fit in a HtL crossing.
Using values from the London Cycle Design standard the minimum width for a junction with cycle lanes on each side and 2 traffic lanes at exit and one at entry is 11.7m. Other geometries are given in the table below.
Road Names Postcode Lat/Long
Kennington Road/Kennington Park Rd (A3) SE11 4PZ 51.4843/-0.1102
See post at https://southwarkcyclists.org.uk/a-hold-the-left-junction-finally-built/ for details
Whitechapel Rd (A11)/Vallance Rd (B108) E1 7QA 51.5184/-0.0629
Mile End Rd (A11)/Grove Rd, Burdett Rd (A1205) E3 4PL 51.5250/-0.0348
Clapham Rd (A3)/South Lambeth Rd (A203) SW8 1UG 51.4731/-0.1217
Clapham Rd (A3)/Stockwell Rd (A203) SW8 1UG 51.4724/-0.1222
Note the two A11 junctions on CS2 are only partial implementations on the E-W arms. The Stockwell versions have Hold-the-Left on only 1 arm of the junction. These partial implementations do not get the full benefit of Hold-the-Left, but they do show that drivers and cyclists can easily navigate this type of junction.
Minimum width needed
A common claim is that there is not enough room for the extra cycle lane plus the island needed between traffic lanes. These add 1.5-2m (cycle lane) and 1.2-1.5m (island), so a total of 2.7 to 3.5m.
Because pedestrians can cross in one phase it is possible to remove, or very much narrow, any central island. This will save in the region of 2m. In addition, at any junction where HGVs are less than 10% of traffic it is possible to reduce traffic lanes to 2.5m from the usual 3m. On a 3 lane road this provides 1.5m to play with. From this arithmetic it can be seen that at a conventional signalised junction with 2 stage crossings it will always be possible to fit in a HtL crossing.
Using values from the London Cycle Design standard the minimum width for a junction with cycle lanes on each side and 2 traffic lanes at exit and one at entry is 11.7m. Other geometries are given in the table below.
Hold the left in action
Stockwell, CS6 on the A3 heading south. In this Streetview snapshot you can see the cyclists and straight on motor vehicles being held while cars make the left turn. Cars are exiting the left-adjacent arm of the junction at the same time (not very clear in the snapshot). On a succeeding stage cyclists and general traffic go straight on.