The Ranty Highwayman)
SUNDAY, 29 JANUARY 2017
I blogged about kerbs over three years ago and this week, I return to the subject (albeit briefly).
In truth, this is more of an update on kerbs and their use with stepped cycle tracks (from a UK perspective). Believe it or not, there have been some UK kerb developments, but I think we are still missing tools which would really make things easy (which the Dutch already have been using for years).
You might want to get up to speed by reading my previous post, but the key reasons we use kerbs are as follows;
In designing cycle tracks, these principles hold, because we are ultimately building little roads for cycles and so we need to use kerbs as part of that process.
Using kerbs as restraint to prevent vehicles leaving the carriageway is clearly very important as is providing demarcation. The way in this can be achieved varies considerably, but in general, it leads to the position that kerbs next to motor traffic are there to stop (or at least discourage) encroachment into cycling space and that kerbs use to demarcate space from pedestrians should be forgiving.
Stopping encroachment by traffic is a matter of degree, and depends on the height of the kerb face presented to the carriageway (as well as the amount of lateral space between the carriageway and the track). The usual type of kerb found edging a carriageway in the UK will be half-battered (HB2 type) with a nominal “face” (or height) of 100 to 125mm;
As common with UK kerbs, the unit is 915mm long (3 feet). The overall height of the kerb is 255mm, it’s 125mm wide and on the face, the top section is battered back from the vertical by around 12.5 degrees. If you used this type of kerb by the carriageway to support a stepped cycle track, there is no particular issue until we get to driveways, where we would drop the kerb height down to 25mm (using a transition kerb and a bull-nosed kerb; a bull-nosed kerb is square rather than battered with a rounded “nose” at the traffic side).