Transportation planning forecasts trips and chooses facilities (roads, transit) to match land use and policy goals.

Scope (transportation planning)

This page covers strategic and project-level transport planning: trip-making, networks, and policy choices that influence mode share and infrastructure need. In South Africa, regional and municipal integrated transport plans, IDPs, and environmental or heritage processes often frame studies. The trip calculator is a toy illustration (population × rate)—real models use zone systems, land use, time of day, and calibrated trip generation models.

Trip generation spot check (illustrative)

  1. Define the study unit (e.g. population, households, or floor area) and match it to the trip rate source.
  2. Multiply units by trips per unit per day to get a rough daily trip total for that factor alone.
  3. In full studies, split by purpose (HBW, HBO, …), apply peak factors, and separate production and attraction by zone.
  4. Feed outputs into distribution, modal split, and assignment (see figures) using planning software per your mandate.

Transportation Engineering — Transportation Planning

Land use, travel demand, and networks—so investment matches trips people actually make.

Introduction

Transportation planning links people and activities to movement: how many trips occur, where they go, which modes they use, and how loads distribute on roads and transit. Classic four-step models proceed from trip generation through distribution, modal split, and traffic assignment; many regions also use activity-based or strategic tools. Policy layers—road space allocation, pricing, and non-motorised priority—affect outcomes as much as concrete and steel.

Flowchart of the four-step model: trip generation, trip distribution, modal split, traffic assignment
Four-step model (generation → distribution → modal split → assignment). See licence on Wikimedia Commons
Pictogram of sustainable transport hierarchy from walking to private motor vehicle
Sustainable transport hierarchy (policy context for mode choice). See licence on Wikimedia Commons

What transport planning produces

  • Demand forecasts — trips, mode shares, and corridor loads for design years.
  • Alternatives analysis — compare projects, TDM measures, and land-use scenarios.
  • Equity and environment — accessibility, emissions, and noise screening.
  • Programming — prioritised lists aligned with funding and policy.

Standards and guidance (South Africa)

Studies typically align with municipal or provincial transport plans, National Land Transport Act processes where applicable, and project-specific terms of reference. Coordinate with traffic engineering for operational detail and environmental specialists for EIA needs—this page does not replace a full travel-demand model sign-off.

Illustrative daily trips   T ≈ (units) × (trips per unit per day)

Notation (common)

  • PA / productions–attractions — trips leaving or entering a zone.
  • OD matrix — origin–destination flows between zones.
  • Modal split — share of trips by walk, cycle, transit, or car.
  • LOS — level of service (often used after assignment to links).

Examples in practice

  • Greenfield township: trip generation from dwelling counts and land-use categories.
  • CBD cordon: peak-hour person trips and public transport capacity.
  • Freight corridor: heavy-vehicle OD and pavement / geometric implications.
  • Transit line: ridership forecasts and park-and-ride catchments.

Calculator — trip generation (illustrative)

Enter a count of population or dwelling units and a trip rate (trips per unit per day). Output is their product—use only as a sanity check alongside proper trip generation models.

T ≈ (units) × (trips/unit/day)

Daily trips

Illustrative daily trip total ≈ (population or dwelling units) × (trips per unit per day).

Key terms

Trip generation
Trips produced or attracted by a zone as a function of land use and activity.
Trip rate
Trips per household, person, or floor area—taken from surveys or manuals for the study context.

Software and travel-demand modelling

Network building, matrices, and scenario testing use commercial or open tools. Examples (official sites):

  • PTV Visum — macroscopic multi-modal demand and assignment.
  • Citilabs Cube — travel demand modelling and network analysis.
  • Emme — transportation planning and modelling (INRO).
  • TransCAD — GIS-based transportation planning (Caliper).

No product endorsement—model structure, calibration data, and validation must match your terms of reference and governance requirements.

Diagram sources

Educational figures. Files in Images/transportation-planning/ were downloaded from Wikimedia Commons into this repo (not copied from other topic folders). Confirm licence on each Commons file page before reuse.