Overview

Traffic jams are not inevitable. They are a math problem. Transport Engineers design the veins and arteries of the city. They decide where the roads go, how long the light stays green, and how to move a million people to work every morning without gridlock.

Core Idea

The core idea is Flow. Treating cars like fluid in a pipe.

Formal Definition

The application of technology and scientific principles to the planning, functional design, operation, and management of facilities for any mode of transportation. Subfields: Traffic Engineering, Highway Engineering, Public Transport.

Intuition

  • The Funnel: If you have 4 lanes merging into 2, you get a bottleneck. Transport engineers try to widen the funnel or slow down the flow before the bottleneck (Ramp Meters).
  • Induced Demand: If you build more roads, traffic gets worse. Why? Because more people decide to drive. (Braess’s Paradox).

Examples

  • Roundabouts: They are safer and more efficient than 4-way stops (because cars don’t have to stop completely), but Americans hate them.
  • High-Speed Rail: Moving people at 200mph. It requires tracks that are perfectly straight and flat.
  • Bus Rapid Transit (BRT): A subway on wheels. Buses with their own dedicated lanes.

Common Misconceptions

  • More lanes = Less traffic: Almost never true in the long run. The only way to reduce traffic is congestion pricing or better public transit.
  • Modal Split: The percentage of people who drive vs. walk vs. take the bus. Engineers try to shift the split away from cars.
  • Last Mile Problem: The train gets you to the station, but how do you get to your house? (Scooters, Bikes).

Applications

  • Smart Cities: Traffic lights that talk to cars and turn green when you approach.

Criticism / Limitations

  • Car-Centric: For 70 years, we designed cities for cars, not people. This destroyed neighborhoods and made us fat. Modern transport engineering is trying to fix this (Complete Streets).

Further Reading

  • Speck, Jeff. Walkable City.