Cities contain multiple transportation systems that operate simultaneously. Roads, rail lines, and pedestrian pathways form interconnected networks. These systems have developed over extended periods.

Road networks consist of different categories of streets. Major arteries carry high traffic volumes between districts. Smaller streets provide access to individual blocks and buildings. Highway systems connect cities and facilitate longer-distance travel. The hierarchy of road types determines traffic capacity and flow patterns.

Public transit systems include buses, trains, and other vehicles that follow established routes. Rail systems may operate above ground, at ground level, or in underground tunnels. Bus routes typically use existing road infrastructure. The coverage and frequency of public transit vary significantly between cities.

Pedestrian infrastructure includes sidewalks, crosswalks, and footbridges. Sidewalk width and condition affect how easily people can walk through urban areas. Crosswalks provide designated locations for pedestrians to cross streets. Some cities have developed extensive networks of pedestrian-only zones.

Bicycle infrastructure has expanded in many cities over recent decades. Dedicated bike lanes separate cyclists from motor vehicle traffic. Bike-sharing systems allow people to rent bicycles for short trips. The extent of bicycle infrastructure influences how many residents choose cycling as a transportation method.

Traffic signals and signs regulate movement through transportation networks. Signal timing affects traffic flow at intersections. Signage provides directions and indicates rules at different locations. These regulatory elements coordinate the movement of different transportation modes.

Transportation networks require ongoing maintenance and periodic upgrades. Road surfaces deteriorate with use and weather exposure. Rail systems need regular inspections and repairs. Cities allocate resources to maintain and improve transportation infrastructure over time.