> If you're manufacturing the car from scratch just build a digital bus into the frame.
And just how would you do this?
The frame is metal - it isn't plastic; so to move control signals around, you need to have a harness. That harness, on the majority of cars today, is attached to clips that are mounted to the frame (inside the vehicle), behind the interior fascia plastic. Google "vehicle wire harness" and look at some pictures to get an idea; most of the harness is behind the dash, with additional branches leading to the doors (locks, windows, speakers, etc), up the A-pillars (rearview mirror and dome light, or other accessories), up the B-pillars (air bags, more speakers), toward the rear (gas tank, brake lights, etc), and elsewhere. There's a ton of wiring in the interior of a car.
There's a separate harness inside the engine compartment, clipped mostly to the firewall and fender area, with branches going to various spots in the compartment (too many to name); that harness is generally connected in some manner to the interior harness of the vehicle, thru a pass-thru on the firewall. This may be a connector, or just a hole the wires are routed through. Sometimes, the junction will be via a computer in the engine compartment; the point being that there are many ways it is done.
Engineers over the years have worked to reduce the number of wires and such in the wiring harness; one of the more recent ways has been the nearly universal adoption of the CAN bus. It is essentially a robust vehicle communications bus with a differentially signaled system, using two wires. Of course, there are bunch of these in a vehicle.
I think eventually they'll move to a fiber-optic system for signals, with the only wires remaining for power.
Embed channels in the unibody. Seal power+digital rails in the channels and provide replaceable hubs at joints (which avoids some problems with CAN transceiver issues, and simplifies maintenance). Use plugs that can be sealed in place to connect sensors. The only wires, if any are needed, are between the sensor and a point on the frame, which might be a few centimeters apart.
Unibodies already are subject to replacement upon severe damage and the replaced part would include the data rails. Attached sensors could be disconnected and rewired or replaced. Fiber would be just as vulnerable to crash and transceivers would probably cost more, and it certainly wouldn't be less complex, other than perhaps EMI.
A lot of modern car design is a result of balancing complexity against maintenance cost. A lot of these factors will go away in a driverless electic world.
And just how would you do this?
The frame is metal - it isn't plastic; so to move control signals around, you need to have a harness. That harness, on the majority of cars today, is attached to clips that are mounted to the frame (inside the vehicle), behind the interior fascia plastic. Google "vehicle wire harness" and look at some pictures to get an idea; most of the harness is behind the dash, with additional branches leading to the doors (locks, windows, speakers, etc), up the A-pillars (rearview mirror and dome light, or other accessories), up the B-pillars (air bags, more speakers), toward the rear (gas tank, brake lights, etc), and elsewhere. There's a ton of wiring in the interior of a car.
There's a separate harness inside the engine compartment, clipped mostly to the firewall and fender area, with branches going to various spots in the compartment (too many to name); that harness is generally connected in some manner to the interior harness of the vehicle, thru a pass-thru on the firewall. This may be a connector, or just a hole the wires are routed through. Sometimes, the junction will be via a computer in the engine compartment; the point being that there are many ways it is done.
Engineers over the years have worked to reduce the number of wires and such in the wiring harness; one of the more recent ways has been the nearly universal adoption of the CAN bus. It is essentially a robust vehicle communications bus with a differentially signaled system, using two wires. Of course, there are bunch of these in a vehicle.
I think eventually they'll move to a fiber-optic system for signals, with the only wires remaining for power.