Roads and Transport

Why This Matters

Without roads, every settlement is an island. You can have the best metalworking, the finest crops, and the most advanced medicine, but if you cannot move goods between communities, specialization is impossible and trade collapses. A person carries 20 kg on their back. A pack animal carries 80 kg. A cart on a dirt track carries 300 kg. A wagon on a good road carries 2,000 kg. Roads multiply human capability by a factor of 100.

Route Selection and Planning

Before you move a single shovel of dirt, plan the route. Bad route choices waste enormous labor and produce roads that wash out, flood, or become impassable.

Choosing the Path

Follow these priorities in order:

1. Follow natural contours. Ridge lines and valley floors are natural highways. Ridge roads drain naturally and avoid river crossings. Valley roads follow flat ground but need drainage.
2. Avoid swamps and floodplains. Soft ground devours road-building effort. Route around wetlands even if it adds distance.
3. Minimize river crossings. Each crossing needs a bridge or ford. Cross at the narrowest, shallowest point with firm banks.
4. Keep gradients manageable. Loaded wagons cannot climb steep hills. Maximum grade for animal-drawn vehicles: 8-10%. For heavily loaded wagons: 5%.
5. Use existing game trails. Animals find the easiest paths. Their trails often follow ideal gradients and avoid obstacles.

Surveying the Route

You need to know elevations and distances before building.

Simple surveying tools:

• Level line: Fill a long tube (gut, bamboo) with water. The water level at both ends is identical — this gives you a horizontal reference over any distance.
• Plumb bob: Gravity gives you perfect vertical.
• Measuring rope: A known-length rope for distances. Stretch it tight — sag introduces error.
• Ranging poles: Straight sticks planted vertically. Sight along them to verify straight sections.

The 1-in-20 Rule for Gradients

A 5% grade (1 meter rise per 20 meters horizontal) is the maximum comfortable gradient for loaded wagons. To check: over 20 paces (roughly 15-16 meters), the elevation change should not exceed 0.75-0.8 meters. Use your water level to verify.

Trail Clearing and Grading

Basic Trail (Foot and Pack Animal)

The simplest road is a cleared, leveled trail. Even this makes an enormous difference compared to bushwhacking.

Steps:

1. Clear vegetation to a width of 2-3 meters (enough for two loaded pack animals to pass)
2. Remove stumps and large rocks from the path
3. Fill low spots with packed earth or gravel
4. Cut drainage ditches on the uphill side of any slope to divert water away from the trail
5. On slopes, cut the trail into the hillside (bench cut) rather than building up — cut surfaces are more stable than fill

Grading for Wheeled Vehicles

Wheeled vehicles require a smoother, wider, and firmer surface.

Width: 3-4 meters minimum (one-lane with occasional passing places). 5-6 meters for two-way traffic.

Crown: The road surface should be higher in the center than the edges (crowned). A 2-3% slope from center to edges sheds water. Without crowning, water pools on the road and destroys it.

Compaction: After grading, compact the surface. A heavy stone roller pulled by animals works. Alternatively, drive loaded wagons back and forth over the surface.

Drainage — The Single Most Important Factor

Water Destroys Roads

More roads fail from poor drainage than from any other cause. Water softens the subgrade, erodes the surface, and freezes to crack foundations. Every road-building decision should prioritize getting water away from the road surface as quickly as possible.

Drainage Systems

Type	Where to Use	Construction
Side ditches	Both sides of any road	V-shaped, 30 cm deep minimum, sloped to drain toward a watercourse
Cross drains	Where water crosses the road path	Stone-lined channels under the road, angled 30 degrees to the road direction
Culverts	Major water crossings under the road	Stone arch or log pipe buried under the road surface
French drains	Wet areas, spring zones	Trench filled with gravel, covered with soil. Water drains through gravel
Crown	Entire road surface	2-3% slope from center to edges
Turnouts	Inside curves, where water collects	Paved channels directing water to downhill ditches

Building a Culvert

1. Dig a trench across the road bed, sloped slightly to one side
2. Line the bottom and sides with flat stones
3. Bridge the top with flat stone slabs or split logs
4. Cover with a layer of smaller stones (prevents soil washing into the culvert)
5. Fill with compacted earth to road surface level
6. The opening on each end should be visible and kept clear of debris

Road Construction Methods

Gravel Road (Simplest All-Weather Surface)

A gravel road can handle moderate traffic in all weather conditions and is the most practical starting point for most communities.

Layers (bottom to top):

1. Subgrade — Natural soil, cleared and compacted. Remove topsoil (organic material rots and settles).
2. Base course — Large stones (5-10 cm), 15-20 cm deep. Pack tightly. These distribute load.
3. Surface course — Smaller gravel (1-3 cm), 10-15 cm deep. This is the wearing surface.
4. Binding fines — A thin layer of fine material (sand, clay-gravel mix) to fill voids and create a smooth surface. Compact thoroughly.

Total depth: 25-35 cm of stone above the subgrade.

The Best Gravel Is Angular, Not Round

Crushed stone with sharp edges locks together and stays in place. Round river gravel rolls and shifts under load. If you have access to rock you can break with hammers, crushed stone is far superior. River gravel works as a base layer but makes a poor surface.

Roman Road Technique

The Romans built roads that survived 2,000 years. Their technique used four layers and demanded enormous labor but produced a surface that could carry heavy military traffic in any weather.

The four layers (bottom to top):

1. Statumen — Large foundation stones (15-30 cm), laid in a trench cut 30-45 cm below ground level. This is the structural base.
2. Rudus — Crushed stone, broken pottery, or rubble in lime morite (cement), 20-25 cm thick. This is a rigid, waterproof layer.
3. Nucleus — Fine gravel or sand mixed with lime cement, 15-20 cm thick, compacted. Smooth, dense layer.
4. Summa crusta — Large flat paving stones (30+ cm across, 15 cm thick) set in mortar. The wearing surface.

Total depth: 60-100 cm. Enormously labor-intensive but nearly indestructible.

Key Roman innovations:

• Roads were raised above surrounding terrain (the “agger”) for drainage
• Cambered surface (crowned) to shed water
• Stone curbs on both sides to contain the road layers
• Ditches on both sides

Brick and Stone Paving

For town centers, marketplaces, or high-traffic areas, a paved surface is worth the investment.

Brick paving:

1. Prepare a compacted base (gravel, 15-20 cm)
2. Lay a sand bed (3-5 cm) — this levels irregularities
3. Set bricks in a pattern. Herringbone is strongest for wheeled traffic (bricks at 45 degrees interlock under load). Running bond (bricks all pointing the same way) is easier but shifts more.
4. Sweep sand into joints between bricks
5. Compact with a roller or tamper

Stone paving (cobblestones):

1. Select stones with at least one flat side
2. Set them flat-side up in a sand bed
3. Pack smaller stones in the gaps
4. Sweep sand into remaining voids
5. The surface will be rougher than brick but extremely durable

The Wheel

Solid Wheels

The earliest wheels (around 3500 BC) were solid discs cut from planks.

Building a solid wheel:

1. Take three thick planks (5-8 cm thick hardwood)
2. Edge-join them with wooden dowels and glue into a square panel
3. Scribe a circle and cut with a saw
4. Drill or cut a square center hole for the axle
5. Optionally, add a metal hub liner (reduces wear)

Limitations: Heavy, no shock absorption, prone to splitting along the grain. But simple to build and adequate for slow, heavy loads on reasonable roads.

Spoked Wheels — The Critical Upgrade

Spoked wheels are 60-70% lighter than solid wheels of the same size. Lighter wheels mean less rolling resistance, faster travel, less wear on the road, and easier on the draft animals.

Components of a spoked wheel:

Part	Function	Material
Hub	Center block, holds axle	Hardwood (elm, oak) or cast iron
Spokes	Connect hub to rim	Straight-grained hardwood (oak, hickory, ash)
Felloes (rim segments)	Curved sections forming the outer ring	Steam-bent hardwood
Tire	Metal band around the outside	Wrought iron or steel

Building spoked wheels (simplified):

1. Hub: Turn a cylinder on a lathe (or carve by hand). Drill an axle hole through the center. Drill spoke holes radially around the circumference — typically 10-14 spokes.
2. Spokes: Shape straight-grained blanks into tapered rounds. The thick end fits the hub, the thin end fits the rim. Each spoke should be slightly compressed when assembled (under tension) — this keeps the wheel tight.
3. Felloes: Steam-bend or saw curved sections of wood. Drill holes to receive spoke ends. Typically 6-7 felloe sections form the complete rim.
4. Assembly: Drive spokes into the hub. Fit felloe sections onto spoke ends. The wheel should be slightly too tight — forcing the felloes on compresses the spokes, creating a pre-loaded, self-tightening structure.
5. Dishing: The spokes should angle slightly outward (like a shallow cone), not lie flat. This dished shape resists lateral loads when the wagon leans in turns.

Metal Tires

An iron tire protects the wooden rim from wear and holds the wheel together.

Shrink-fitting a tire:

1. Forge an iron band slightly smaller in circumference than the wheel rim (about 3 mm per foot of diameter smaller)
2. Heat the band until it expands enough to slip over the rim
3. Place it on the wheel and quench immediately with water
4. As the iron cools, it contracts and grips the rim with enormous force

Tire Fitting Requires Speed

You have seconds between placing the hot iron tire and quenching. Have water ready — buckets or a trough. The wood will scorch but should not catch fire if you are fast enough. This is a two-person job minimum, four people for large wheels.

Axle Design

Fixed vs. Rotating Axles

Type	Description	Advantages	Disadvantages
Fixed axle (wheels spin on axle)	Axle bolted to frame, wheels rotate on the axle ends	Simple construction, easy to replace wheels	Higher friction, axle ends wear
Rotating axle (axle spins with wheels)	Axle turns in bearings mounted on the frame	Lower friction, less axle wear	More complex, wheels cannot turn independently

For simple carts, a fixed axle with wheels spinning on greased axle ends is the easiest and most practical design.

Lubrication

Without lubrication, wood-on-wood or wood-on-metal friction wastes energy, generates heat, and wears parts rapidly.

Lubricants from available materials:

Lubricant	Source	Quality	Notes
Animal fat (tallow)	Rendered beef/mutton fat	Good	Melts in high heat, attracts dirt
Lard	Rendered pig fat	Good	Better heat resistance than tallow
Beeswax + oil mix	Beeswax melted into animal fat	Very good	Stays in place, resists washing out
Pine tar	Destructive distillation of pine	Good	Water resistant, traditional naval lubricant
Graphite in grease	Charcoal powder in animal fat	Excellent	Graphite reduces friction dramatically

Tar and Grease Mix

A mixture of pine tar and tallow in equal parts makes an excellent axle grease. The tar resists water washout (critical in rain) and the tallow provides lubrication. Add fine charcoal powder for even better performance.

Bearing Materials

As you advance, upgrade axle bearings from wood to metal:

1. Hardwood on hardwood — Adequate for very slow, light use. Wears rapidly.
2. Hardwood on iron — Better. The iron axle end wears slowly; the wooden hub liner is replaceable.
3. Bronze bushings — Excellent. Cast a bronze (copper + tin alloy) sleeve to line the hub. Bronze on iron is one of the best low-friction bearing combinations.
4. Roller bearings — Hardened steel rollers between inner and outer races. High precision required. Best performance but difficult to manufacture.

Cart and Wagon Construction

Two-Wheel Cart

The simplest wheeled vehicle. One axle, two wheels, two shafts extending forward for the draft animal.

Advantages: Simple, light, maneuverable, can tilt to dump loads. Disadvantages: Part of the load weight rests on the animal through the shafts.

Construction:

1. Build a flat platform (1 x 1.5 meters) from planks on a sturdy frame
2. Mount the axle beneath the platform, positioned so roughly 60% of the platform is behind the axle (this keeps weight slightly behind the wheels, with manageable shaft weight on the animal)
3. Attach two shafts to the front of the platform, angling upward to harness height
4. Add sideboards for containing loads

Load capacity: 200-400 kg depending on wheel size, road quality, and draft animal.

Four-Wheel Wagon

Greater capacity and the load weight rests entirely on the wheels, not the animal.

The steering problem: The front axle must pivot for turning. Solutions:

• Fifth wheel: A horizontal pivot plate under the front of the wagon body. The entire front axle assembly rotates on this pivot.
• Turntable: A circular bearing plate. More complex but smoother turning.

Construction key points:

• The wagon body sits on top of the axle assemblies, connected by bolster plates
• Leaf springs between body and axle (flat iron strips stacked and clamped) absorb shock — a major comfort and cargo protection upgrade
• Brakes: A lever-operated brake pad pressing against the rear wheel rim. Essential on hills.

Load Capacity Calculations

Factor	Impact on Capacity
Wheel diameter	Larger wheels = easier rolling over obstacles, less rolling resistance
Tire width	Wider tires = less sinking on soft ground
Road surface	Paved: 2-3x capacity vs dirt. Gravel: 1.5-2x vs dirt
Grade	Halve capacity for every 5% grade increase
Animal	Horse: 500-800 kg pull on flat road. Ox: 400-600 kg, but more sustained

Rule of thumb: On a good gravel road on flat ground, a two-horse team can pull a wagon loaded with 1,500-2,000 kg at walking pace for 25-30 km per day.

Animal Harness Design

The Collar vs. Yoke Problem

Ancient harnesses used a throat-and-girth strap that pressed on the horse’s windpipe. The harder the horse pulled, the more it choked. This design limited horses to roughly 500 kg of pull.

The horse collar (invented in China around 500 AD, reached Europe by 900 AD) shifted the load to the horse’s shoulders, where it could exert full strength. Pull capacity doubled or tripled.

Building a horse collar:

1. Bend a U-shaped frame from two pieces of hardwood, padded with straw and leather
2. The collar sits on the horse’s shoulders, with the opening at the top
3. Hames (curved metal or wood bars) attach to the outside of the collar
4. Traces (chains or leather straps) connect the hames to the vehicle

For oxen: A yoke across the horns or shoulders works well — oxen push against the yoke with their strong neck and shoulder muscles. The ox yoke is simpler than a horse collar and oxen tolerate crude harnesses better.

Animal	Best Harness	Speed	Endurance	Pull Force	Best For
Horse	Collar + hames	Fast (6-8 km/h)	6-8 hours	High (short bursts)	Distance travel, lighter loads
Ox	Yoke (neck or horn)	Slow (3-4 km/h)	8-10 hours	Steady, sustained	Heavy loads, plowing, rough terrain
Donkey	Breast collar or pack saddle	Medium (4-5 km/h)	Long	Moderate	Mountain trails, small loads
Mule	Collar or breast collar	Medium-fast	Very long	Good	All-around, rough terrain

Oxen Are Better Than Horses for Road Building

Oxen are slower but stronger, more patient, cheaper to feed (grass vs grain), and less prone to injury on rough terrain. For construction hauling and pioneer roads, oxen are superior. Switch to horses once roads are established and speed matters.

Bridge Approaches

Where roads meet rivers or ravines, you need either a ford or a bridge. For bridge construction details, see Bridges. Here, focus on the road approach.

Ford construction (shallow crossings):

1. Pave the riverbed with flat stones if it is soft
2. Grade the approaches at less than 10%
3. Build up stone walls on both sides to prevent erosion of the banks
4. Place marker stones showing safe water depth

Bridge approaches:

• Grade smoothly up to bridge deck level — sudden bumps or drops damage vehicles and loads
• Reinforce approach fill with stone retaining walls
• Pave the approach surface for at least 3 meters before the bridge to prevent erosion

Road Maintenance

An Unmaintained Road Becomes a Ditch Within 5 Years

Roads require ongoing care. Water damage accumulates with every rainstorm. Ruts deepen with every vehicle pass. Without regular maintenance, your road investment is wasted.

Monthly tasks:

• Clear drainage ditches of debris and sediment
• Fill potholes with gravel and compact
• Clear culvert openings

Seasonal tasks:

• After spring thaw: inspect for frost heave damage, re-grade surface
• After heavy rains: check for erosion, repair washouts, re-crown the surface
• Before winter: clear drainage, fill ruts, reinforce weak points

Annual tasks:

• Add fresh surface gravel (roads lose 1-2 cm of surface material per year from traffic and weather)
• Inspect culverts and bridges
• Clear vegetation from road edges (roots damage road structure, shade keeps road wet)

Community organization: Historically, road maintenance was a community obligation. Each household was responsible for maintaining the road section nearest their property, typically 6-10 days of road labor per year. This corvee system worked for millennia and is practical for your community.

What’s Next

Roads are the circulatory system of civilization. They enable:

• Trade and Currency — Reliable transport makes specialization and trade possible between communities
• Internal Combustion — Better roads justify better vehicles; engines need roads to be useful
• Bridges — Major river crossings for your road network

Roads and Transport — At a Glance

Route planning: Follow ridges or valleys. Avoid swamps. Maximum 5% gradient for loaded wagons. Survey with water levels and plumb bobs.

Drainage is everything: Crown the road (2-3% slope), dig side ditches, install culverts at water crossings. Water destroys roads faster than traffic.

Simplest good road: 15-20 cm crushed stone base + 10-15 cm gravel surface + fine binding material. Crown and compact.

Wheels: Start with solid plank wheels. Upgrade to spoked wheels (60-70% lighter). Shrink-fit iron tires for durability.

Axle grease: Pine tar + tallow + charcoal powder. Apply regularly.

Horse collar, not throat strap: The collar doubles pulling power by loading the shoulders instead of choking the horse.

Capacity multiplier: Person (20 kg) → pack animal (80 kg) → cart on dirt (300 kg) → wagon on good road (2,000 kg). Roads multiply carrying capacity 100x.

Maintenance: Monthly ditch clearing and pothole filling. Annual gravel resurfacing. An unmaintained road is a ditch within 5 years.