One bridge, fifteen minutes wider

Luján de Cuyo is divided by the Río Mendoza, a geographic barrier that forces residents to navigate a single congested bus crossing. The city’s municipal government had identified a new bridge as the key infrastructure solution, but needed to understand what it would actually change. We modeled the entire metropolitan accessibility network, assessing travel time from every parcel to key destinations under the current routing constraints and again with the bridge in place.

The simulation revealed that infrastructure alone solves half the problem. A new bridge increases the parcels reachable in 15 minutes by 190% north of Perdriel, from 876 to 2,542 parcels, and expands territory reachable across the southern band by 15%. But the bridge’s full potential only materializes when paired with systematic route redesign, which adds a further 28% reach improvement by eliminating detours and redundant loops that existed even with the new crossing.

The model’s overturned assumption was about causality: a planner sees a barrier and builds a crossing. The simulation showed that the bridge is a necessary condition, not a sufficient one. Residents reaching Parque de la Ribera in 15 minutes rise from 2.2% to 8.7% only when routes are redrawn to exploit the bridge’s new geometry.