The Wrong Side of my Car

The blog that wants to go obsolete

Driveways: we’re still doing it wrong

A while ago it was time again to complain about footpaths.

So what is it this time? Auckland Transport has rebuilt the footpaths on Birkenhead Avenue. While this is by itself a good idea, they have, on the northbound side, once again gone for the pump track design. So for their effort, they get a significantly less useful path than what they could have gotten for their money.

So what is wrong with it? Are we even supposed to build it like this?

NZTA

Our national transport agency actually has guidance about how driveway crossings over footpaths should be built. In short, as any even marginally competent agency would prescribe, the footpath should remain as level and uninterrupted as possible.

Where a path crosses a property access driveway, the path should have a continuous grade across the driveway and preferably the same crossfall as the adjoining path segments.4

The crossfall should be as flat as practicable consistent with achieving adequate drainage, and no greater than 1:50 (2%) *1. To achieve this, the sloped part of the driveway should be within the street furniture zone and/ or the adjacent private property. It may be necessary to lower the footpath (see Parallel graphic below).

Oops.

In Auckland, I know of exactly one properly built crossing, on Northcote Road, which looks almost exactly like one of the NZTA example photos:

Auckland

Auckland’s guidance exists, and it is, uuhhmmmm…

Special.

Not that it matters because we’re also completely ignoring that one. But let’s look at it.

So, does that look like the NZTA guidance? Not at all. About half of the width of the footpath is taken up by that ramp. 15% is much more than 2%, that is annoying even as an able bodied person just walking alone. A 900mm ramp is just not necessary.

Auckland, but actually Auckland

I don’t know what sort of guidance is used, but the current design, with its full-width crossfall and sneaky upstand is built too consistently to not come from some planning document. I just don’t know where it is.

Apart from the crossfall, another problem is that bump where it goes back up to footpath level. This forms a speed bump, which is annoying enough. But worse, due to the splay, it forms a speed bump that is misaligned. If you have a stroller, you will have to resist its tendency to bounce back on that bump right into the roadway. And you’ll have this at every driveway.

And if you do roll off, the little upstand at the gutter will catch those little wheels when you try to pull it back, and you’ll properly get stuck.

Or, did you ever see those images of Dutch people carrying groceries home in a crate in front of them on a bicycle? Don’t try that here. Yes, this design is also used on shared paths. And anything in that crate will go flying out unless you ride at walking pace. *2

Apart from that, this design also allows cars to turn out at speed. This is a real hazard for people walking on the footpath, and for people with long shared driveways.

Alternative Auckland design

So, that plan. There are actually a couple of specimens that sort of look like that.

Yes, I have encountered these with a stroller and, well, it is higher stakes. That ramp takes up half the width of the path, so you can go around it. But if you forget and roll down, the twice as steep slope will make it twice as hard to pull it up again.

Alternatives

OK, so the alternative would be to follow NZTA guidance, maybe?

The path should still, as closely as practical, resemble the footpath without the driveway cut.

And you know what, for cars this would already work well. Despite not being what a traffic engineer calls a mountable kerb, a typical footpath kerb is easily mountable with a car. Bicycles or wheelchairs would have a harder time mounting that though. And my high school physics tells me that cars will tend to dig out those kerbstones when mounting them. *3

So we can make a little bit of real ‘mountable kerb’. We can quibble a bit over how steep that ramp should be. I have observed a lot of 45° kerbstones in Belgium. If you turn into your driveway over one of these at speed, you will do that only once, unless you are a slow leaner and then your car suspension will hate you.

We have also those specialised tiles called ‘inritbanden’, which have a slope of about 1:3. That would make the ramp a bit wider, but still a lot less wide than half the entire footpath width.

And as a bonus, if a new driveway appears, it seems like less work than ripping up the full width of the footpath.

First world problems

Well, at least we have actual footpaths, so we have at least the option to walk. It could be much worse, there are plenty of cities overseas, where walking a few blocks is nearly impossible even in the city centre, and even outside 40 storey apartments.

But still, this seems such an unnecessary, dumb way to make walking worse. How much can it possibly cost extra to do this properly?

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