Start where the truck leaves the road and walk it forward
The useful way to answer this for your own property is to walk it in the order the driver will drive it, starting at the road. The first pinch point is almost always the turn in off the pavement. A truck that long cannot take a sharp entrance in one motion, and if the drive meets the road at a tight angle the driver has to swing wide across the road first, which depends on what is coming and how much shoulder there is.
Look at the edges of that entrance while you are standing there. A drop off, a soft shoulder or a bank sitting right at the edge of the apron all take away room the truck needs on the swing, even though the drive itself measures plenty wide.
Width is not the whole story, the swing is
A long vehicle does not follow its own front wheels. Going around a bend, the rear wheels track inside the line the cab takes, so the truck needs room on both sides of a corner at once. That is why a drive that a pickup handles without thinking can stop a mixer at the first bend, and why the answer is never just a width in feet.
Fixed things are the ones to worry about. A stone wall, a bank, a gate post, a corner of the house, a well head, mature trees on both sides of a pinch. Movable things are easy. Park the cars somewhere else that morning, move the trailer, open the gate wide and take the trash cans in. Every foot you can clear on the inside of a turn is a foot the driver does not have to find somewhere else.
Overhead is where people get caught out
This is the part nobody checks, because standing in a driveway you look at the ground. A mixer is tall, the drum rides high, and the chute at the back comes up higher still when it is raised for travel. Low tree limbs over the drive, a service line drooping across it, a carport, a garage eave or the roof of a covered entry can all stop the truck at a point where there is no good way to back out.
Walk your drive once and look up the whole way. Limbs can be cut before pour day and that is an easy fix. A line across the drive is not something anybody should be moving or ducking under on their own, and it may simply mean the truck stops short of that point and the concrete goes the rest of the way on hose.
The spot where it stops, and what has to be clear there
Wherever the ready mix truck ends up, it needs firm and reasonably level ground under it, because the drum has to keep turning and the chute has to swing through an arc at the back. It also needs people to be able to work around it safely without walking between the truck and the forms. How far the chute itself reaches is its own question with its own answer on this site, and it is the thing most people overestimate.
On a pump day the ask is simpler than you might expect. The truck does not have to reach the pour at all. It has to be able to back up to the hopper on our pump, which is usually sitting on the drive or the road shoulder on solid ground.
- Firm, level ground the truck can sit on with the drum turning
- Room behind it for the chute to swing without hitting anything
- Room for the crew to work without being pinned against the forms
- Water available, and everybody agreed on where the washout goes
When the room is not there, the hose goes instead of the truck
Plenty of good sites simply cannot give a loaded mixer what it needs, and that does not put the pour in doubt. Our trailer-mounted line pump tows in behind a truck, so it fits through gaps a loaded mixer would never attempt. We set it on a flat spot the mixer can reach, and run 2.5 or 3 inch hose the rest of the distance, through a yard gate, along the side of a house, over a bank or in through a door opening, so the concrete lands where the finishers want it.
Tight access is one of the three things that puts a pump on a job, along with foundation work and pours of roughly 8 cubic yards and up. So if your drive is long, narrow, steep or crowded, say so when you call rather than hoping it works out on the day. The machine sits on our own yard and our own guys run it, which means the pour gets planned around your access instead of around what somebody else has available that week.