Study: Metro Systems Cut Driving Significantly More Than Other Forms of Transit

European cities with subway systems have a much lower share of car trips than cities with tram- or bus-based transit systems.

1 minute read

November 12, 2025, 6:00 AM PST

By Diana Ionescu @aworkoffiction


People boarding a train on a crowded Paris subway platform.

Pierre Laborde / Shutterstock

People living in European cities with metro systems drive significantly less than those with access to only trams or no rail-based transit systems, according to a new study from the Complexity Science Hub (CSH).

Using data from 400 cities, researcher Rafael Prieto-Curiel examined the share of car trips compared to active mobility and public transit. “In cities with a metro, the average share of car trips is 37%, compared to 50% in cities with trams only and 54% in cities without rail systems.” Residents of metro cities also use transit much more frequently. 

The effect is more pronounced in larger cities, where the share of car commutes grows uto 63 percent when no metro is present. “Meanwhile, the share of car trips in metro cities remains nearly unchanged at 36%.”

Prieto-Curiel attributes the difference to the fact that trams tend to be slower and have lower passenger capacity than metros. “While trams are often seen as a cost-effective alternative to metro systems, the study shows that metro networks measurably reduce car traffic, whereas this effect cannot be observed for trams.”

Tuesday, November 11, 2025 in Complexity Science Hub

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