What this kerb is telling you

Nobody stops to admire a kerb. That's a shame, because it's the chattiest thing on the street. Every rise, drop and bump is a message, and most of them are aimed at someone who isn't you.

The full-height kerb (about 125 mm) says "this side is for people, that side is for traffic". It keeps rain on the road and drivers off the footway. Simple, and it does it all day without complaint. Drop much below 100 mm and both jobs start to slip.

The flush drop at a crossing says "cross here". It's level so a wheelchair, a buggy or a wheeled suitcase can get across without a jolt. Look down and you'll usually find blister paving too, buff at an uncontrolled crossing and red at a signalised one, so someone who can't see the drop can feel it.

The little 25 mm lip at a driveway says "cars cross here, but slowly". Low enough for tyres, high enough to keep water in the channel and stop the footway turning into a slip road.

The tall kerb at a bus stop says "step straight on". Raised boarding kerbs bring the pavement up to meet the bus floor, so the ramp has less work to do, the driver can pull in tight, and everyone gets on quicker.

The small step between footway and cycle track says "bikes this side, feet that side", without a barrier in sight. Add the ladder and tramline paving where the two meet, and people walking and cycling both know where they stand.

Corduroy paving at the top of steps or a ramp says "careful, change ahead".

None of this is decoration. It's a language, and the best streets speak it clearly and consistently, so nobody has to think about it. When we design a scheme, a lot of the quiet work goes into making sure every kerb is saying the right thing to the right person.

If you've got a layout and want to know what its kerbs are telling people, give us a shout.